ORCID Profile
0000-0001-5995-7040
Current Organisations
University Hospital of Zurich
,
University of Melbourne
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Mycology | Plant Pathology | Crop and Pasture Protection (Pests, Diseases and Weeds) | Microbial Genetics | Crop and pasture production | Molecular Evolution | Microbiology | Crop and Pasture Production | Crop and pasture protection (incl. pests diseases and weeds) | Microbial genetics | Plant Biology | Medical Infection Agents (incl. Prions) | Plant pathology
ANZSRC Socio-Economic Objective (SEO)
Canola | Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Control of Animal Pests, Diseases and Exotic Species in Farmland, Arable Cropland and Permanent Cropland Environments | Control of Plant Pests, Diseases and Exotic Species in Farmland, Arable Cropland and Permanent Cropland Environments | Crop Protection Chemicals | Expanding Knowledge in the Biological Sciences | Infectious Diseases |
Related Links
Publications
Spatially distinct phytohormone responses of individualArabidopsis thalianaroot cells to infection and colonization byFusarium oxysporum
Publisher: Cold Spring Harbor Laboratory
Date: 20-12-2022
DOI: 10.1101/2022.12.20.521292
Abstract: Jasmonic acid (JA), ethylene (ET) and salicylic acid (SA) are the three major phytohormones coordinating a plant’s defense response to pathogenic attack. While JA and ET are assumed to primarily control the defense against necrotrophic pathogens, SA-induced defense responses target mainly biotrophic microbes, and can include drastic measures such as programmed cell death as part of the plant’s hypersensitive response (HR). Fusarium oxysporum is a hemibiotrophic fungal pathogen of several plant species, including many important food crops, and the model plant species Arabidopsis thaliana . Colonization of the plant’s root vascular tissue by the fungus eventually results in wilting and plant death. A general role for JA, ET and SA in combating infection and colonization of the plant by F. oxysporum has been demonstrated, but their distinct roles and modes of action have so far not been described. Here, using high resolution microscopy with fluorescent marker lines of A. thaliana roots infected with F. oxysporum we show that SA acts spatially separate from JA, in a distinct set of root cells immediately neighboring the fungal colonization site. There, SA induces HR to stop the spread of colonization. JA acts in a different, but also clearly defined set of cells, slightly removed from the colonization site, where it initiates a defense response to actively resist the invader. ET is activated in a stretch of cells that covers both, the cells with activated SA and JA signaling, and may be involved in creating these two distinct zones. These results show how the three phytohormones act together, but spatially and functionally separate from each other, to fight this hemibiotrophic pathogen. Such a high-resolution analysis to resolve the plant’s immune response to pathogenic infection on an in idual cell level and in intact tissue has so far been lacking. Colonization of the A . thaliana root tip by F . oxysporum strain Fo 5176 leads to immediate cell death of the colonized and surrounding tissue. As the colonization front progresses through the vasculature, the cell death front moves along with it through not only the vasculature, but also the surrounding tissues. WRKY70 positively regulates salicylic acid (SA) biosynthesis in cells immediately adjacent to the colonized tissue, inducing a hypersensitive response (HR), thereby killing off the cells deemed lost to the intruder, establishing the cell death front. Slightly further removed from the HR zone, WRKY11 induces jasmonate (JA) biosynthesis in cells of the vasculature to launch a defense response aimed at actively repelling the fungus.
Sexual Pheromones in the Fungi
Publisher: Springer Netherlands
Date: 2012
Gene function analysis in the ubiquitous human commensal and pathogen Malassezia genus
Publisher: American Society for Microbiology
Date: 30-12-2016
Abstract: The genus Malassezia includes 14 species that are found on the skin of humans and animals and are associated with a number of diseases. Recent genome sequencing projects have defined the gene content of all 14 species however, to date, genetic manipulation has not been possible for any species within this genus. Here, we develop and then optimize molecular tools for the transformation of Malassezia furfur and Malassezia sympodialis using Agrobacterium tumefaciens delivery of transfer DNA (T-DNA) molecules. These T-DNAs can insert randomly into the genome. In the case of M. furfur , targeted gene replacements were also achieved via homologous recombination, enabling deletion of the ADE2 gene for purine biosynthesis and of the LAC2 gene predicted to be involved in melanin biosynthesis. Hence, the introduction of exogenous DNA and direct gene manipulation are feasible in Malassezia species. IMPORTANCE Species in the genus Malassezia are a defining component of the microbiome of the surface of mammals. They are also associated with a wide range of skin disease symptoms. Many species are difficult to culture in vitro , and although genome sequences are available for the species in this genus, it has not been possible to assess gene function to date. In this study, we pursued a series of possible transformation methods and identified one that allows the introduction of DNA into two species of Malassezia , including the ability to make targeted integrations into the genome such that genes can be deleted. This research opens a new direction in terms of now being able to analyze gene functions in this little understood genus. These tools will contribute to define the mechanisms that lead to the commensalism and pathogenicity in this group of obligate fungi that are predominant on the skin of mammals.
Phytochelatin synthase is required for tolerating metal toxicity in a basidiomycete yeast and is a conserved factor involved in metal homeostasis in fungi
Publisher: Springer Science and Business Media LLC
Date: 28-03-2015
The Uve1 Endonuclease Is Regulated by the White Collar Complex to Protect Cryptococcus neoformans from UV Damage
Publisher: Public Library of Science (PLoS)
Date: 05-09-2013
Galleria mellonella as a model system to study Cryptococcus neoformans pathogenesis
Publisher: American Society for Microbiology
Date: 07-2005
DOI: 10.1128/IAI.73.7.3842-3850.2005
Abstract: Evaluation of Cryptococcus neoformans virulence in a number of nonmammalian hosts suggests that C. neoformans is a nonspecific pathogen. We used the killing of Galleria mellonella (the greater wax moth) caterpillar by C. neoformans to develop an invertebrate host model system that can be used to study cryptococcal virulence, host immune responses to infection, and the effects of antifungal compounds. All varieties of C. neoformans killed G. mellonella . After injection into the insect hemocoel, C. neoformans proliferated and, despite successful phagocytosis by host hemocytes, killed caterpillars both at 37°C and 30°C. The rate and extent of killing depended on the cryptococcal strain and the number of fungal cells injected. The sequenced C. neoformans clinical strain H99 was the most virulent of the strains tested and killed caterpillars with inocula as low as 20 CFU/caterpillar. Several C. neoformans genes previously shown to be involved in mammalian virulence ( CAP59 , GPA1 , RAS1 , and PKA1 ) also played a role in G. mellonella killing. Combination antifungal therapy ( hotericin B plus flucytosine) administered before or after inoculation was more effective than monotherapy in prolonging survival and in decreasing the tissue burden of cryptococci in the hemocoel. The G. mellonella - C. neoformans pathogenicity model may be a substitute for mammalian models of infection with C. neoformans and may facilitate the in vivo study of fungal virulence and efficacy of antifungal therapies.
The Phycomyces madA gene encodes a blue-light photoreceptor for phototropism and other light responses
Publisher: Proceedings of the National Academy of Sciences
Date: 10-03-2006
Abstract: Phycomyces blakesleeanus is a filamentous zygomycete fungus that produces striking elongated single cells that extend up to 10 cm into the air, with each such sporangiophore supporting a sphere containing the spores for dispersal. This organism has served as a model for the detection of environmental signals as erse as light, chemicals, touch, wind, gravity, and adjacent objects. In particular, sporangiophore growth is regulated by light, and it exhibits phototropism by bending toward near-UV and blue wavelengths and away from far-UV wavelengths in a manner that is physiologically similar to plant phototropic responses. The Phycomyces madA mutants were first isolated more than 40 years ago, and they exhibit reduced sensitivity to light. Here, we identify two (duplicated) homologs in the White Collar 1 family of blue-light photoreceptors in Phycomyces . We describe that the madA mutant strains contain point mutations in one of these genes and that these mutations cosegregate with a defect in phototropism after genetic crosses. Thus, the phototropic responses of fungi through madA and plants through phototropin rely on erse proteins however, these proteins share a conserved flavin-binding domain for photon detection.
A tetrad analysis of the basidiomycete fungus Cryptococcus neoformans
Publisher: Oxford University Press (OUP)
Date: 05-2010
DOI: 10.1534/GENETICS.109.113027
Abstract: Cryptococcus neoformans is a basidiomycete fungus that is found worldwide and causes disease in humans and animal species. The fungus grows asexually as a budding yeast. Under laboratory conditions it is capable of sexual reproduction between two mating types. After cell fusion a dikaryotic filament develops, at the tip of which a basidium gives rise to four chains of basidiospores. Because the chains each comprise 10–30 spores, rather than single spores, the analysis of in idual meiotic events has not been attempted in C. neoformans in the style of tetrad analyses performed in other fungal species. Here, the basidiospores from & basidia were micromanipulated and the resultant & progeny analyzed for three genetic markers to understand the sexual process in this fungus, leading to four observations: (i) Marker segregation provides genetic evidence for a single meiotic event within the basidium followed by multiple rounds of mitosis. (ii) Using each basidium as an unordered tetrad, the ADE2 and URA5 genes are linked to their centromeres, consistent with adjacent genomic regions rich in repetitive elements predicted to comprise Cryptococcus centromeres. (iii) Lack of germination of basidiospores is attributed to aneuploidy, rather than dormancy. (iv) Analysis of basidiospores derived from single chains demonstrates that each chain can contain different genotypes. This mechanism of sexual spore production would benefit the species with a high rate of dispersal and at the same time aid in simultaneous dissemination of both mating types to new locations in the environment.
Transmission of Hypervirulence Traits via Sexual Reproduction within and between Lineages of the Human Fungal Pathogen Cryptococcus gattii
Publisher: Public Library of Science (PLoS)
Date: 05-09-2013
A new set of international Leptosphaeria maculans isolates as a resource for elucidation of the basis and evolution of blackleg disease on Brassica napus
Publisher: Wiley
Date: 22-09-2023
DOI: 10.1111/PPA.13801
Analysis of loss of pathogenicity mutants reveals that repeat-induced point mutations can occur in the Dothideomycete Leptosphaeria maculans
Publisher: Elsevier BV
Date: 06-2003
DOI: 10.1016/S1087-1845(02)00588-1
Abstract: Restriction enzyme mediated insertional mutagenesis using a plasmid, pUCATPH, that confers hygromycin resistance, generated loss-of-pathogenicity mutants of Leptosphaeria maculans, the fungus that causes blackleg disease of Brassica napus. Of 516 L. maculans transformants analysed, 12 were pathogenicity mutants. When eight of these mutants were crossed to an isolate that attacks B. napus, cosegregation of pUCATPH sequences and loss of pathogenicity was not observed, suggesting that these mutations were not linked to plasmid sequences. In seven of eight crosses analysed, progeny with the hygromycin resistance gene were hygromycin-sensitive. Sequence analysis of an lified fragment of pUCATPH in six clones derived from one 'silenced' progeny showed mutation of GC to AT on one DNA strand, reminiscent of repeat-induced point mutation (RIP) in Neurospora crassa. One loss-of-pathogenicity mutant had pUCATPH inserted in the promoter of a gene with an open reading frame of 529 amino acids that had no database match. Reintroduction of a wild-type copy of the gene to this mutant restored the ability to form lesions on cotyledons of B. napus.
A glimpse into the basis of vision in the kingdom Mycota
Publisher: Elsevier BV
Date: 11-2010
Identification of the ergC gene involved in polyene drug sensitivity in the Mucorales species Phycomyces blakesleeanus
Publisher: Springer Science and Business Media LLC
Date: 06-11-2021
DOI: 10.1007/S11033-021-06917-6
Abstract: A strain of Phycomyces blakesleeanus (Mucorales, Mucoromycota) that was previously isolated after ultraviolet mutagenesis has altered responses to polyene antifungal drugs, sterol profiles, and phototropism of its sporangia. In this study, the genetic basis for these changes was sought. Two base pair substitutions were identified in the mutant within a P. blakelesleeanus gene that is homologous to others characterized from fungi, such as the Saccharomyces cerevisiae ERG3 gene, encoding sterol Δ5,6-desaturase. The polyene resistance and growth reduction phenotypes co-segregated with mutations in the gene in genetic crosses. The P. blakelesleeanus wild type ergC gene complemented a S. cerevisiae deletion strain of ERG3. This gene discovery may contribute towards better antifungal use in treating mucormycoses diseases caused by related species in the order Mucorales.
Phycomyces MADB interacts with MADA to form the primary photoreceptor complex for fungal phototropism
Publisher: Proceedings of the National Academy of Sciences
Date: 28-04-2009
Abstract: The fungus Phycomyces blakesleeanus reacts to environmental signals, including light, gravity, touch, and the presence of nearby objects, by changing the speed and direction of growth of its fruiting body (sporangiophore). Phototropism, growth toward light, shares many features in fungi and plants but the molecular mechanisms remain to be fully elucidated. Phycomyces mutants with altered phototropism were isolated ≈40 years ago and found to have mutations in the mad genes. All of the responses to light in Phycomyces require the products of the madA and madB genes. We showed that madA encodes a protein similar to the Neurospora blue-light photoreceptor, zinc-finger protein WC-1. We show here that madB encodes a protein similar to the Neurospora zinc-finger protein WC-2. MADA and MADB interact to form a complex in yeast 2-hybrid assays and when coexpressed in E. coli , providing evidence that phototropism and other responses to light are mediated by a photoresponsive transcription factor complex. The Phycomyces genome contains 3 genes similar to wc-1 , and 4 genes similar to wc-2 , many of which are regulated by light in a madA or madB dependent manner. We did not detect any interactions between additional WC proteins in yeast 2-hybrid assays, which suggest that MADA and MADB form the major photoreceptor complex in Phycomyces . However, the presence of multiple wc genes in Phycomyces may enable perception across a broad range of light intensities, and may provide specialized photoreceptors for distinct photoresponses.
Identification of the sex genes in an early diverged fungus
Publisher: Springer Science and Business Media LLC
Date: 2008
DOI: 10.1038/NATURE06453
Abstract: Sex determination in fungi is controlled by a small, specialized region of the genome in contrast to the large sex-specific chromosomes of animals and some plants. Different gene combinations reside at these mating-type (MAT) loci and confer sexual identity invariably they encode homeodomain, alpha-box, or high mobility group (HMG)-domain transcription factors. So far, MAT loci have been characterized from a single monophyletic clade of fungi, the Dikarya (the ascomycetes and basidiomycetes), and the ancestral state and evolutionary history of these loci have remained a mystery. Mating in the basal members of the kingdom has been less well studied, and even their precise taxonomic inter-relationships are still obscure. Here we apply bioinformatic and genetic mapping to identify the sex-determining (sex) region in Phycomyces blakesleeanus (Zygomycota), which represents an early branch within the fungi. Each sex allele contains a single gene that encodes an HMG-domain protein, implicating the HMG-domain proteins as an earlier form of fungal MAT loci. Additionally, one allele also contains a copy of a unique, chromosome-specific repetitive element, suggesting a generalized mechanism for the earliest steps in the evolution of sex determination and sex chromosome structure in eukaryotes.
Recombination hotspots flank the Cryptococcus mating-type locus: Implications for the evolution of a fungal sex chromosome
Publisher: Public Library of Science (PLoS)
Date: 2006
A Ras GTPase associated protein is involved in the phototropic and circadian photobiology responses in fungi
Publisher: Springer Science and Business Media LLC
Date: 21-03-2017
DOI: 10.1038/SREP44790
Abstract: Light is an environmental signal perceived by most eukaryotic organisms and that can have major impacts on their growth and development. The MadC protein in the fungus Phycomyces blakesleeanus (Mucoromycotina) has been postulated to form part of the photosensory input for phototropism of the fruiting body sporangiophores, but the madC gene has remained unidentified since the 1960s when madC mutants were first isolated. In this study the madC gene was identified by positional cloning. All madC mutant strains contain loss-of-function point mutations within a gene predicted to encode a GTPase activating protein (GAP) for Ras. The madC gene complements the Saccharomyces cerevisiae Ras-GAP ira1 mutant and the encoded MadC protein interacts with P. blakesleeanus Ras homologs in yeast two-hybrid assays, indicating that MadC is a regulator of Ras signaling. Deletion of the homolog in the filamentous ascomycete Neurospora crassa affects the circadian clock output, yielding a pattern of asexual conidiation similar to a ras-1 mutant that is used in circadian studies in N. crassa . Thus, MadC is unlikely to be a photosensor, yet is a fundamental link in the photoresponses from blue light perceived by the conserved White Collar complex with Ras signaling in two distantly-related filamentous fungal species.
pGG-PIP: A GreenGate (GG) entry vector collection with Plant Immune system Promoters (PIP)
Publisher: Cold Spring Harbor Laboratory
Date: 20-12-2022
DOI: 10.1101/2022.12.20.521163
Abstract: The regulatory sequences controlling the expression of a gene (i.e., the promoter) are essential to properly understand a gene’s function. From their use in mutant complementation assays, to studying their responsiveness to different stimuli via transcriptional reporter lines or using them as proxy for the activation of certain pathways, assays using promoter sequences are valuable tools for insight into the genetic architecture underlying plant life. The GreenGate (GG) system is a plant-specific variant of the Golden Gate assembly method, a modular cloning system that allows the hierarchical assembly of in idual donor DNA fragments into one expression clone via a single reaction step. Here, we present a collection of 75 GG entry vectors carrying putative regulatory sequences for Arabidopsis thaliana genes involved in many different pathways of the plant immune system, designated Plant Immune system Promoters (PIP). This pGG-PIP entry vector set enables the rapid assembly of expression vectors to be used for transcriptional reporters of plant immune system components, mutant complementation assays when coupled with coding sequences, mis-expression experiments for genes of interest, or the targeted use of CRISPR/Cas9 genome editing. We used pGG-PIP vectors to create fluorescent transcriptional reporters in A . thaliana and demonstrated the potential of these reporters to image the responsiveness of specific plant immunity genes to infection and colonization by the fungal pathogen Fusarium oxysporum . Using the PLANT ELICITOR PEPTIDE (PEP) pathway as an ex le, we show that several components of this pathway are locally activated in response to colonization by the fungus.
Sensing the environment: Lessons from fungi
Publisher: Springer Science and Business Media LLC
Date: 2007
DOI: 10.1038/NRMICRO1578
Abstract: All living organisms use numerous signal-transduction systems to sense and respond to their environments and thereby survive and proliferate in a range of biological niches. Molecular dissection of these signalling networks has increased our understanding of these communication processes and provides a platform for therapeutic intervention when these pathways malfunction in disease states, including infection. Owing to the expanding availability of sequenced genomes, a wealth of genetic and molecular tools and the conservation of signalling networks, members of the fungal kingdom serve as excellent model systems for more complex, multicellular organisms. Here, we review recent progress in our understanding of how fungal-signalling circuits operate at the molecular level to sense and respond to a plethora of environmental cues.
Hormonal and proteomic analyses of southern blight disease caused by Athelia rolfsii and root chitosan priming on Cannabis sativa in an in vitro hydroponic system
Publisher: Wiley
Date: 09-2023
DOI: 10.1002/PLD3.528
Sequencing the Genomes of the First Terrestrial Fungal Lineages: What Have We Learned?
Publisher: MDPI AG
Date: 18-07-2023
DOI: 10.3390/MICROORGANISMS11071830
Abstract: The first genome sequenced of a eukaryotic organism was for Saccharomyces cerevisiae, as reported in 1996, but it was more than 10 years before any of the zygomycete fungi, which are the early- erging terrestrial fungi currently placed in the phyla Mucoromycota and Zoopagomycota, were sequenced. The genome for Rhizopus delemar was completed in 2008 currently, more than 1000 zygomycete genomes have been sequenced. Genomic data from these early- erging terrestrial fungi revealed deep phylogenetic separation of the two major clades—primarily plant—associated saprotrophic and mycorrhizal Mucoromycota versus the primarily mycoparasitic or animal-associated parasites and commensals in the Zoopagomycota. Genomic studies provide many valuable insights into how these fungi evolved in response to the challenges of living on land, including adaptations to sensing light and gravity, development of hyphal growth, and co-existence with the first terrestrial plants. Genome sequence data have facilitated studies of genome architecture, including a history of genome duplications and horizontal gene transfer events, distribution and organization of mating type loci, rDNA genes and transposable elements, methylation processes, and genes useful for various industrial applications. Pathogenicity genes and specialized secondary metabolites have also been detected in soil saprobes and pathogenic fungi. Novel endosymbiotic bacteria and viruses have been discovered during several zygomycete genome projects. Overall, genomic information has helped to resolve a plethora of research questions, from the placement of zygomycetes on the evolutionary tree of life and in natural ecosystems, to the applied biotechnological and medical questions.
Somaclonal breeding of reed canarygrass (Phalaris arundinacea L.)
Publisher: Wiley
Date: 06-2003
Three new pathogenicity genes in Leptosphaeria maculans identified by Agrobacterium-mediated insertional mutagenesis
Publisher: Springer Science and Business Media LLC
Date: 19-06-2023
A conserved Zn2Cys6 transcription factor, identified in a spontaneous mutant from in vitro passaging, is involved in pathogenicity of the blackleg fungus Leptosphaeria maculans
Publisher: Elsevier BV
Date: 07-2021
Cryptococcus neoformans gene involved in mammalian pathogenesis identified by a Caenorhabditis elegans progeny-based approach
Publisher: American Society for Microbiology
Date: 12-2005
DOI: 10.1128/IAI.73.12.8219-8225.2005
Abstract: Caenorhabditis elegans can serve as a substitute host for the study of microbial pathogenesis. We found that mutations in genes of the fungal pathogen Cryptococcus neoformans involved in mammalian virulence allow C. elegans to produce greater numbers of progeny than when exposed to wild-type fungus. We used this property to screen a library of C. neoformans mutants for strains that permit larger C. elegans brood sizes. In this screen, we identified a gene homologous to Saccharomyces cerevisiae ROM2. C. neoformans rom2 mutation resulted in a defect in mating and growth defects at elevated temperature or in the presence of cell wall or hyperosmolar stresses. An effect of the C. neoformans rom2 mutation in virulence was confirmed in a murine inhalation infection model. We propose that a screen for progeny-permissive mutants of microorganisms can serve as a high-throughput method for identifying novel loci related to mammalian pathogenesis.
Identification of a gene cluster for the synthesis of the plant hormone abscisic acid in the plant pathogen Leptosphaeria maculans
Publisher: Elsevier BV
Date: 09-2019
DOI: 10.1016/J.FGB.2019.04.015
Abstract: Leptosphaeria maculans is an ascomycetous fungus that causes the disease blackleg on Brassica napus (canola). In spite of the importance of the disease worldwide, the mechanisms of disease development are poorly understood. Secondary metabolites, which are one of the common virulence factors of pathogenic fungi, have not been extensively explored from this fungus. An RNA-seq dataset was examined to find genes responsible for secondary metabolite synthesis by this fungus during infection. One polyketide synthase gene, pks5, was found to be upregulated during the early biotrophic stage of development. In addition to pks5, six other genes adjacent to the pks5 gene, including one encoding a Zn(II)
Regional scalable priorities for national biodiversity and carbon conservation planning in Asia
Publisher: American Association for the Advancement of Science (AAAS)
Date: 27-08-2021
Abstract: Scalable ranking approaches can map effective bio ersity and climate targets for national conservation action by 2030.
Deciphering the model pathogenic fungus Cryptococcus neoformans
Publisher: Springer Science and Business Media LLC
Date: 30-08-2005
DOI: 10.1038/NRMICRO1245
Abstract: Cryptococcus neoformans is a basidiomycete fungal pathogen of humans that has erged considerably from other model fungi such as Neurospora crassa, Aspergillus nidulans, Saccharomyces cerevisiae and the common human fungal pathogen Candida albicans. The recent completion of the genome sequences of two related C. neoformans strains and the ongoing genome sequencing of three other ergent Cryptococcus strains with different virulence phenotypes and environmental distributions should improve our understanding of this important pathogen. We discuss the biology of C. neoformans in light of this genomic data, with a special emphasis on the role that evolution and sexual reproduction have in the complex relationships of the fungus with the environment and the host.
Sterol Demethylation Inhibitor Fungicide Resistance in Leptosphaeria maculans is Caused by Modifications in the Regulatory Region of ERG11
Publisher: Scientific Societies
Date: 05-2020
DOI: 10.1094/PDIS-10-19-2088-RE
Abstract: Blackleg is a worldwide disease of canola (Brassica napus), caused by a complex of fungal species in the genus Leptosphaeria, that impacts canola production and seed quality. Demethylation inhibitor (DMI) fungicides that target sterol 14α-demethylase are an integral part of disease control. Here, we report six DMI-resistant isolates of Leptosphaeria maculans and two different types of genetic modification related to the resistance. Analysis of the regulatory region of the DMI target gene ERG11 (also known as CYP51) revealed a 275-bp insertion in two of the isolates and three long terminal repeat retrotransposons (5,263, 5,267, and 5,248 bp) inserted in the promoter region of three resistant isolates. Genetic approaches confirmed that these elements are responsible for DMI resistance in L. maculans and crosses show segregation consistent with a single locus. Reverse-transcription quantitative PCR assays demonstrated that the 275-bp insertion increases ERG11 gene expression, conferring DMI fungicide resistance both in vitro and in planta. Moreover, transformation of a susceptible isolate of L. maculans with ERG11 driven by a promoter containing the 275-bp insertion increased resistance to tebuconazole. A minimal shift of the values of concentration whereby 50% of the mycelial growth is inhibited in vitro was observed in resistant isolates containing long terminal repeat retrotransposons nevertheless, these isolates were able to develop significant lesions on cotyledons from fungicide-treated seedlings. This is the first report of genetic modifications in L. maculans relating to DMI fungicide resistance.
Cryptococcus neoformans and Cryptococcus gattii, the etiologic agents of cryptococcosis
Publisher: Cold Spring Harbor Laboratory
Date: 07-2015
Light controls growth and development via a conserved pathway in the fungal kingdom
Publisher: Public Library of Science (PLoS)
Date: 15-03-2005
Transcriptomic responses of the basidiomycete yeast Sporobolomyces sp. to the mycotoxin patulin
Publisher: Springer Science and Business Media LLC
Date: 09-03-2016
Morphology and its underlying genetic regulation impact the interaction between Cryptococcus neoformans and its hosts.
Publisher: Oxford University Press (OUP)
Date: 03-04-2015
DOI: 10.1093/MMY/MYV012
The contribution of the White Collar complex to Cryptococcus neoformans virulence is independent of its light-sensing capabilities
Publisher: Elsevier BV
Date: 12-2018
Small scale functional genomics of the blackleg fungus, Leptosphaeria maculans: Analysis of a 38 kb region
Publisher: Springer Science and Business Media LLC
Date: 2003
DOI: 10.1071/AP03057
Globisporangium and Pythium Species Associated with Yield Decline of Pyrethrum (Tanacetum cinerariifolium) in Australia
Publisher: MDPI AG
Date: 17-03-2023
Abstract: Pyrethrum (Tanacetum cinerariifolium) cultivation in Australia, which accounts for the majority of global production of natural insecticidal pyrethrins, is affected by a persistent yield decline which in part is caused by a complex of pathogens. Globisporangium and Pythium species were isolated from crown and roots of pyrethrum plants showing stunting and brown discoloration of crown tissue, and from soil adjacent to diseased plants from yield-decline-affected sites in Tasmania and Victoria, Australia. Ten known Globisporangium species (Globisporangium attrantheridium, G. erinaceum, G. intermedium, G. irregulare, G. macrosporum, G. recalcitrans, G. rostratifingens, G. sylvaticum, G. terrestris and G. ultimum var. ultimum), two new Globisporangium species (Globisporangium capense sp. nov. and Globisporangium commune sp. nov.) and three Pythium species (Pythium diclinum/lutarium, P. tracheiphilum and P. vanterpoolii) were identified through morphological studies and multigene phylogenetic analyses using ITS and Cox1 sequences. Globisporangium ultimum var. ultimum, G. sylvaticum, G. commune sp. nov. and G. irregulare were most abundant. Globisporangium attrantheridium, G. macrosporum and G. terrestris were reported for the first time in Australia. Seven Globisporangium species were pathogenic on both pyrethrum seeds (in vitro assays) and seedlings (glasshouse bioassays), while two Globisporangium species and three Pythium species only caused significant symptoms on pyrethrum seeds. Globisporangium irregulare and G. ultimum var. ultimum were the most aggressive species, causing pyrethrum seed rot, seedling d ing-off and significant plant biomass reduction. This is the first report of Globisporangium and Pythium species causing disease in pyrethrum globally and suggests that oomycete species in the family Pythiaceae may have an important role in the yield decline of pyrethrum in Australia.
Isolation of strains and their genome sequencing to analyze the mating system ofOphiocordyceps robertsii
Publisher: Cold Spring Harbor Laboratory
Date: 02-12-2022
DOI: 10.1101/2022.12.02.518814
Abstract: The fungal genus Ophiocordyceps contains a number of insect pathogens. One of the best known of these is Ophiocordyceps sinensis , which is used in Chinese medicine and its overharvesting threatens sustainability hence, alternative sources are being sought. Ophiocordyceps robertsii , found in Australia and New Zealand, has been proposed to be a close relative to O. sinensis , but little is known about this species despite being also of historical significance. Here, O. robertsii strains were isolated into culture and high coverage draft genome sequences obtained and analyzed. This species has a large genome expansion, as also occurred in O. sinensis . The mating type locus was characterized, indicating a heterothallic arrangement whereby each strain has an idiomorphic region of two ( MAT1-2-1, MAT1-2-2 ) or three ( MAT1-1-1, MAT1-1-2, MAT1-1-3 ) genes flanked by the conserved APN2 and SLA2 genes. These resources provide a new opportunity for understanding the evolution of the expanded genome in the homothallic species O. sinensis , as well as capabilities to explore the pharmaceutical potential in a species endemic to Australia and New Zealand. Ophiocordyceps robertsii is a close relative of O. sinensis and has a large genome but with a heterothallic mating system.
Mystique of Phycomyces blakesleeanus is a peculiar mitochondrial genetic element that is highly variable in DNA sequence while subjected to strong negative selection
Publisher: Springer Science and Business Media LLC
Date: 30-10-2018
Emergence of Cladosporium macrocarpum disease in canola (Brassica napus)
Publisher: Springer Science and Business Media LLC
Date: 08-10-2021
Author Reply to Peer Reviews of pGG-PIP: A GreenGate (GG) entry vector collection with Plant Immune system Promoters (PIP)
Publisher: EMBO
Date: 18-06-2023
Diversity of Backusella (Mucoromycotina) in south-eastern Australia revealed through polyphasic taxonomy
Publisher: Naturalis Biodiversity Center
Date: 2021
DOI: 10.3767/PERSOONIA.2021.46.01
Abstract: Here we explore the ersity of one morphologically distinguishable genus in the Mucoromycotina , Backusella , in south-eastern Australia. We isolated more than 200 strains from locations across the states of Victoria and Tasmania. Characterization of these strains using a combination of approaches including morphology, sucrose utilization and whole genome sequencing for 13 strains, revealed 10 new species. The genetic basis for interspecies variation in sucrose utilization was found to be the presence of a gene encoding an invertase enzyme. The genus Backusella is revised and a new key for species identification produced. Given that we have more than doubled the number of species in this genus, this work demonstrates that there may be considerable undiscovered species ersity in the early erging fungal lineages.
The “Bipartite” Structure of the First Genome of Ampelomyces quisqualis, a Common Hyperparasite and Biocontrol Agent of Powdery Mildews, May Point to Its Evolutionary Origin from Plant Pathogen
Publisher: Oxford University Press (OUP)
Date: 08-2021
DOI: 10.1093/GBE/EVAB182
Abstract: Powdery mildews are among the most important plant pathogens worldwide, which are often attacked in the field by mycoparasitic fungi belonging to the genus Ampelomyces. The taxonomy of the genus Ampelomyces is unresolved, but well-supported molecular operational taxonomic units were repeatedly defined suggesting that the genus may include at least four to seven species. Some Ampelomyces strains were commercialized as biocontrol agents of crop pathogenic powdery mildews. However, the genomic mechanisms underlying their mycoparasitism are still poorly understood. To date, the draft genome of a single Ampelomyces strain, designated as HMLAC 05119, has been released. We report a high-quality, annotated hybrid draft genome assembly of A. quisqualis strain BRIP 72107, which, based on phylogenetic analyses, is not conspecific with HMLAC 05119. The constructed genome is 40.38 Mb in size, consisting of 24 scaffolds with an N50 of 2.99 Mb and 96.2% completeness. Our analyses revealed “bipartite” structure of Ampelomyces genomes, where GC-balanced genomic regions are interspersed by longer or shorter stretches of AT-rich regions. This is also a hallmark of many plant pathogenic fungi and provides further evidence for evolutionary affinity of Ampelomyces species to plant pathogenic fungi. The high-quality genome and annotation produced here provide an important resource for future genomic studies of mycoparasitisim to decipher molecular mechanisms underlying biocontrol processes and natural tritrophic interactions.
Congenic strains for genetic analysis of virulence traits in Cryptococcus gattii
Publisher: American Society for Microbiology
Date: 07-2013
DOI: 10.1128/IAI.00018-13
Abstract: Cryptococcus gattii is responsible for a large outbreak of potentially fatal disease that started in the late 1990s on Vancouver Island, Canada. How this fungus and the outbreak isolates in particular cause disease in immunocompetent people is unknown, with differing hypotheses. To explore genetic contributions, a pair of congenic a and α mating type strains was generated by a series of 11 backcrosses to introgress the MAT locus from a nonoutbreak strain into the background of strain R265, isolated from a Vancouver Island patient. The congenic pair was used to investigate three traits: mitochondrial inheritance, the effect of the MAT alleles on virulence, and the impact of a predicted virulence factor on pathogenicity. The two congenic strains show the same virulence in different models of cryptococcosis and equivalent levels of competition in coinfection assays. These results rule out a role of the MAT locus and mitochondrial genotype as major virulence factors in the outbreak strains. Disruption of Bwc2, a light-dependent transcription factor, resulted in reduced virulence, consistent with a similar function in the related species Cryptococcus neoformans . The C. gattii congenic strains represent a new resource for exploring the evolution of virulence in the C. neoformans-C. gattii clade.
Novel gene functions required for melanization of the human pathogen Cryptococcus neoformans
Publisher: Wiley
Date: 22-07-2005
DOI: 10.1111/J.1365-2958.2005.04779.X
Abstract: The ability to produce melanin is a key virulence factor in many fungal pathogens including the human basidiomycete pathogen Cryptococcus neoformans, a major cause of life-threatening infections among immunocompromised persons. Despite the significance of melanin biosynthesis in virulence of C. neoformans, the cellular and molecular processes involved in this pathway have not yet been fully elucidated. Here, we used Agrobacterium to isolate insertional mutants and screened 12 000 mutants to uncover genes involved in melanin production in C. neoformans. Four new mutant alleles of the well-known melanin biosynthesis gene, LAC1, which encodes laccase were identified, and the T-DNA was shown to have a possible predisposition for insertion into the promoters of genes, in particular LAC1. Melanization in C. neoformans is dependent on five additional genes identified in this screen encoding homologues of the copper transporter Ccc2, the copper chaperone Atx1, the chitin synthase Chs3, the transcriptional coactivator Mbf1 and the chromatin-remodelling enzyme Snf5. Illumination of the molecular and genetic components of this virulence pathway reveals potential novel targets for drug development against C. neoformans and provides further insight into the intimate relationship between metal ion homeostasis and melanin biosynthesis.
Exploring and exploiting the connection between mitochondria and the virulence of human pathogenic fungi
Publisher: Informa UK Limited
Date: 03-2018
Phylogenetic and phylogenomic definition of Rhizopus species
Publisher: Oxford University Press (OUP)
Date: 06-2018
Abstract: Phylogenomic approaches have the potential to improve confidence about the inter-relationships of species in the order Mucorales within the fungal tree of life. Rhizopus species are especially important as plant and animal pathogens and bioindustrial fermenters for food and metabolite production. A dataset of 192 orthologous genes was used to construct a phylogenetic tree of 21 Rhizopus strains, classified into four species isolated from habitats of industrial, medical and environmental importance. The phylogeny indicates that the genus Rhizopus consists of three major clades, with R. microsporus as the basal species and the sister lineage to R. stolonifer and two closely related species R. arrhizus and R. delemar. A comparative analysis of the mating type locus across Rhizopus reveals that its structure is flexible even between different species in the same genus, but shows similarities between Rhizopus and other mucoralean fungi. The topology of single-gene phylogenies built for two genes involved in mating is similar to the phylogenomic tree. Comparison of the total length of the genome assemblies showed that genome size varies by as much as threefold within a species and is driven by changes in transposable element copy numbers and genome duplications.
Ferrochelatase is a conserved downstream target of the blue light-sensing White collar complex in fungi
Publisher: Microbiology Society
Date: 08-2010
Abstract: Light is a universal signal perceived by organisms, including fungi, in which light regulates common and unique biological processes depending on the species. Previous research has established that conserved proteins, originally called White collar 1 and 2 from the ascomycete Neurospora crassa , regulate UV/blue light sensing. Homologous proteins function in distant relatives of N. crassa , including the basidiomycetes and zygomycetes, which erged as long as a billion years ago. Here we conducted microarray experiments on the basidiomycete fungus Cryptococcus neoformans to identify light-regulated genes. Surprisingly, only a single gene was induced by light above the commonly used twofold threshold. This gene, HEM15 , is predicted to encode a ferrochelatase that catalyses the final step in haem biosynthesis from highly photoreactive porphyrins. The C. neoformans gene complements a Saccharomyces cerevisiae hem15 Δ strain and is essential for viability, and the Hem15 protein localizes to mitochondria, three lines of evidence that the gene encodes ferrochelatase. Regulation of HEM15 by light suggests a mechanism by which bwc1 / bwc2 mutants are photosensitive and exhibit reduced virulence. We show that ferrochelatase is also light-regulated in a white collar -dependent fashion in N. crassa and the zygomycete Phycomyces blakesleeanus , indicating that ferrochelatase is an ancient target of photoregulation in the fungal kingdom.
Pathogenicity genes of phytopathogenic fungi
Publisher: Wiley
Date: 07-2001
DOI: 10.1046/J.1464-6722.2001.00070.X
Abstract: Summary Recently many fungal genes have been identified that, when disrupted, result in strains with a reduction or total loss of disease symptoms. Such pathogenicity genes are the subject of this review. The large number of pathogenicity genes identified is due to the application of tagged mutagenesis techniques (random or targeted). Genes have been identified with roles in the formation of infection structures, cell wall degradation, overcoming or avoiding plant defences, responding to the host environment, production of toxins, and in signal cascades. Additionally, genes with no database matches and with 'novel' functions have also been found. Improved technologies for mutation analysis and for sequencing and analysing fungal genomes hold promise for identifying many more pathogenicity genes.
Light sensing in Aspergillus fumigatus highlights the case for establishing new models for fungal photobiology
Publisher: American Society for Microbiology
Date: 07-2013
Abstract: Microbes inhabit erse environmental locations, and many species need to shift their physiology between different niches. To do this effectively requires the accurate sensing of and response to the environment. For pathogens, exposure to light is one major change between a free-living saprophyte lifestyle and causation of disease within the host. However, how light may act as a signal to influence pathogenesis, on the side of either the host or the pathogen, is poorly understood. Research during the last 2 decades has uncovered aspects about the machinery for light sensing in a small number of fungi. Now, Fuller et al. have initiated studies into the role that light and two photosensor homologs play in the behavior of the ubiquitous fungal pathogen Aspergillus fumigatus [K. K. Fuller, C. S. Ringelberg, J. J. Loros, and J. C. Dunlap, mBio 4(2):e00142-13, 2013, doi:10.1128/mBio.00142-13]. Light represses the germination of A. fumigatus spores and enhances resistance to ultraviolet light, oxidative stresses, and cell wall perturbations. The phenotypes of the strains with mutations in the LreA and FphA homologs revealed that these sensors control some, but not all, responses to light. Furthermore, interactions occur between blue and red light signaling pathways, as has been described for a related saprophytic species, Aspergillus nidulans . Genome-wide transcript analyses found that about 2.6% of genes increase or decrease their transcript levels in response to light. This use of A. fumigatus establishes common elements between model filamentous species and pathogenic species, underscoring the benefits of extending photobiology to new species of fungi.
Openness and visibility of fungal bio(techno)logy
Publisher: Springer Science and Business Media LLC
Date: 23-10-2017
Contrasted patterns in mating-type chromosomes in fungi: hotspots versus coldspots of recombination
Publisher: Elsevier BV
Date: 12-2015
Eca1, a sarcoplasmic/endoplasmic reticulum Ca2+-ATPase, is involved in stress tolerance and virulence in Cryptococcus neoformans
Publisher: American Society for Microbiology
Date: 07-2007
DOI: 10.1128/IAI.01977-06
Abstract: The basidiomycetous fungal pathogen Cryptococcus neoformans is adapted to survive challenges in the soil and environment and within the unique setting of the mammalian host. A C. neoformans mutant was isolated with enhanced virulence in a soil amoeba model that nevertheless exhibits dramatically reduced growth at mammalian body temperature (37°C). This mutant phenotype results from an insertion in the ECA1 gene, which encodes a sarcoplasmic/endoplasmic reticulum (ER) Ca 2+ -ATPase (SERCA)-type calcium pump. Infection in murine macrophages, amoebae ( Acanthamoeba castellanii ), nematodes ( Caenorhabditis elegans ), and wax moth ( Galleria mellonella ) larvae revealed that the eca1 mutants are virulent or hypervirulent at permissive growth temperatures but attenuated at 37°C. Deletion mutants lacking the entire ECA1 gene were also hypersensitive to the calcineurin inhibitors cyclosporin and FK506 and to ER and osmotic stresses. An eca1 Δ cna1 Δ mutant lacking both Eca1 and the calcineurin catalytic subunit was more sensitive to high temperature and ER stresses than the single mutants and exhibited reduced survival in C. elegans and attenuated virulence towards wax moth larvae at temperatures that permit normal growth in vitro. Eca1 is likely involved in maintaining ER function, thus contributing to stress tolerance and virulence acting in parallel with Ca 2+ -calcineurin signaling.
Experimental and Natural Evolution of the Cryptococcus Neoformans and Cryptococcus Gattii Species Complex
Publisher: Wiley
Date: 03-08-2013
Deep amplicon sequencing reveals extensive allelic diversity in the erg11/CYP51 promoter and allows multi-population DMI fungicide resistance monitoring in the canola pathogen Leptosphaeria maculans
Publisher: Elsevier BV
Date: 10-2023
Biological functions of the autophagy-related proteins Atg4 and Atg8 in Cryptococcus neoformans
Publisher: Public Library of Science (PLoS)
Date: 06-04-2020
Identification of isolates of the plant pathogen Leptosphaeria maculans with resistance to the triazole fungicide fluquinconazole using a novel in planta assay
Publisher: Public Library of Science (PLoS)
Date: 15-11-2017
Putting Fungal Biology and Biotechnology to the test
Publisher: Springer Science and Business Media LLC
Date: 18-04-2023
The photobiology of microbial pathogenesis
Publisher: Public Library of Science (PLoS)
Date: 26-11-2009
A gene for carotene cleavage required for pheromone biosynthesis and carotene regulation in the fungus Phycomyces blakesleeanus
Publisher: Elsevier BV
Date: 05-2012
DOI: 10.1016/J.FGB.2012.03.002
Abstract: Mating and sexual development in fungi are controlled by molecular mechanisms that are specific for each fungal group. Mating in Phycomyces blakesleeanus and other Mucorales requires pheromones derived from β-carotene. Phycomyces mutants in gene carS accumulate large amounts of β-carotene but do not enter the sexual process. We show that carS encodes a β-carotene-cleaving oxygenase that catalyzes the first step in the biosynthesis of a variety of apocarotenoids, including those that act as pheromones. Therefore carS mutants cannot stimulate their sexual partners, although they respond to them. CarS catalyzes the biosynthesis of a β-ring-containing apocarotenoid that inhibits the activity of the carotenogenic enzyme complex in vegetative cells and provides a feedback regulation for the β-carotene pathway. The carS gene product is a keystone in carotenogenesis and in sexual reproduction.
Development of resources for the analysis of gene function in Pucciniomycotina red yeasts
Publisher: Elsevier BV
Date: 07-2011
DOI: 10.1016/J.FGB.2011.03.003
Abstract: The Pucciniomycotina is an important subphylum of basidiomycete fungi but with limited tools to analyze gene functions. Transformation protocols were established for a Sporobolomyces species (strain IAM 13481), the first Pucciniomycotina species with a completed draft genome sequence, to enable assessment of gene function through phenotypic characterization of mutant strains. Transformation markers were the URA3 and URA5 genes that enable selection and counter-selection based on uracil auxotrophy and resistance to 5-fluoroorotic acid. The wild type copies of these genes were cloned into plasmids that were used for transformation of Sporobolomyces sp. by both biolistic and Agrobacterium-mediated approaches. These resources have been deposited to be available from the Fungal Genetics Stock Center. To show that these techniques could be used to elucidate gene functions, the LEU1 gene was targeted for specific homologous replacement, and also demonstrating that this gene is required for the biosynthesis of leucine in basidiomycete fungi. T-DNA insertional mutants were isolated and further characterized, revealing insertions in genes that encode the homologs of Chs7, Erg3, Kre6, Kex1, Pik1, Sad1, Ssu1 and Tlg1. Phenotypic analysis of these mutants reveals both conserved and ergent functions compared with other fungi. Some of these strains exhibit reduced resistance to detergents, the antifungal agent fluconazole or sodium sulfite, or lower recovery from heat stress. While there are current experimental limitations for Sporobolomyces sp. such as the lack of Mendelian genetics for conventional mating, these findings demonstrate the facile nature of at least one Pucciniomycotina species for genetic manipulation and the potential to develop these organisms into new models for understanding gene function and evolution in the fungi.
Analysis of Repeat Induced Point (RIP) Mutations in Leptosphaeria maculans Indicates Variability in the RIP Process Between Fungal Species
Publisher: Oxford University Press (OUP)
Date: 02-11-2018
DOI: 10.1534/GENETICS.118.301712
Abstract: Gene duplication contributes to evolutionary potential, yet many duplications in a genome arise from the activity of “selfish” genetic elements such as transposable elements. Fungi have a number of mechanisms by which they limit the expansion of transposons, including Repeat Induced Point mutation (RIP). RIP has been best characterized in the Sordariomycete Neurospora crassa, wherein duplicated DNA regions are recognized after cell fusion, but before nuclear fusion during the sexual cycle, and then mutated. While “signatures” of RIP appear in the genome sequences of many fungi, the species most distant from N. crassa in which the process has been experimentally demonstrated to occur is the Dothideomycete Leptosphaeria maculans. In the current study, we show that similar to N. crassa, nonlinked duplications can trigger RIP however, the frequency of the generated RIP mutations is extremely low in L maculans (& 0.1%) and requires a large duplication to initiate RIP, and that multiple premeiotic mitoses are involved in the RIP process. However, a single sexual cycle leads to the generation of progeny with unique haplotypes, despite progeny pairs being generated from mitosis. We hypothesize that these different haplotypes may be the result of the deamination process occurring post karyogamy, leading to unique mutations within each of the progeny pairs. These findings indicate that the RIP process, while common to many fungi, differs between fungi and that this impacts on the fate of duplicated DNA.
Sex and speciation: The paradox that non-recombining DNA promotes recombination
Publisher: Elsevier BV
Date: 10-2011
Changes in allele frequencies of avirulence genes in the blackleg fungus, Leptosphaeria maculans, over two decades in Australia
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/CP16411
Abstract: Cultivation of canola (oilseed rape, rapeseed Brassica napus) in many parts of the world relies on the use of cultivars carrying resistance genes that recognise avirulence products of the major canola pathogen, Leptosphaeria maculans. However, widespread cultivation of plants with such resistance provides the potential for evolution of the pathogen population to overcome resistance by altering the proportion of avirulence v. virulence alleles. In this study, the frequencies of avirulence genes were measured for 2091 Australian isolates dating from the late 1980s to present. Frequencies of avirulence genes changed over time. Analysis of isolates from the Eyre Peninsula, where canola is intensively cultivated, indicated that changes in allele frequencies at the AvrLm1, AvrLm4 and AvrLm6 loci could be correlated with the widespread planting of cultivars carrying specific resistance genes. These data show that determining avirulence allele frequencies in L. maculans populations provides power to anticipate which cultivars will be most successful in future growing seasons.
Characterization of a gene (sp1) encoding a secreted protein from Leptosphaeria maculans, the blackleg pathogen of Brassica napus
Publisher: Wiley
Date: 31-10-2002
DOI: 10.1046/J.1364-3703.2002.00144.X
Abstract: SUMMARY A gene (sp1) encoding a 12.3 kDa protein with a predicted secretion signal has been characterized from Leptosphaeria maculans, the dothideomycete that causes blackleg disease of canola (Brassica napus). This protein (SP1) contains four cysteine residues and shows a high sequence similarity to proteins from other ascomycetes. L. maculans sp1 has been placed on genetic and physical maps. This gene is expressed during the infection of B. napus cotyledons 10 days post-inoculation, coinciding with detection of the constitutively expressed fungal gene, beta-tubulin. L. maculans sp1, along with opsin and glyceraldehyde phosphate dehydrogenase, is light regulated. A recombinant SP1 protein expressed in Escherichia coli and a crude protein fraction secreted by L. maculans induced an autofluorescence response on B. napus leaves. The sp1 gene was mutated by targeted gene disruption whereby a hygromycin resistance gene was inserted. Such mutants caused similar-sized lesions on B. napus cotyledons as those caused by the wild-type isolate, indicating that sp1 is not crucial for pathogenicity of L. maculans on B. napus. This is the first report of disruption of this gene in any fungus.
Sex determination in the first-described sexual fungus
Publisher: American Society for Microbiology
Date: 11-2011
DOI: 10.1128/EC.05149-11
Abstract: The original report of sex in fungi dates 2 centuries ago to the species Syzygites megalocarpus (Mucoromycotina). The organism was subsequently used in 1904 to represent self-fertile homothallic species when the concepts of heterothallism and homothallism were developed for the fungal kingdom. In this study, two putative sex / MAT loci were identified in in idual strains of S. megalocarpus , accounting for its homothallic behavior. The strains encode both of the high-mobility-group domain-containing proteins, SexM and SexP, flanked by RNA helicase and glutathione oxidoreductase genes that are found adjacent to the mating-type loci in other Mucoromycotina species. The presence of pseudogenes and the arrangement of genes suggest that the origin of homothallism in this species is from a heterothallic relative, obtained via a chromosomal rearrangement to switch two alleles into two separated loci within a single genetic background. Similar events have given rise to homothallic species from heterothallic species in ascomycete fungi, demonstrating that conserved forces shape the evolution of sex determination and speciation in highly erged fungi.
DNA Mutations Mediate Microevolution between Host-Adapted Forms of the Pathogenic Fungus Cryptococcus neoformans
Publisher: Public Library of Science (PLoS)
Date: 04-10-2012
A spontaneous mutation in DNA polymerase POL3 during in vitro passaging causes a hypermutator phenotype in Cryptococcus species
Publisher: Elsevier BV
Date: 02-2020
Cryptococcus neoformans virulence gene discovery through insertional mutagenesis
Publisher: American Society for Microbiology
Date: 04-2004
DOI: 10.1128/EC.3.2.420-429.2004
Abstract: Insertional mutagenesis was applied to Cryptococcus neoformans to identify genes associated with virulence attributes. Using biolistic transformation, we generated 4,300 nourseothricin ( NAT )-resistant strains, of which 590 exhibited stable resistance. We focused on mutants with defects in established virulence factors and identified two with reduced growth at 37°C, four with reduced production of the antioxidant pigment melanin, and two with an increased sensitivity to nitric oxide (NO). The NAT insertion and mutant phenotypes were genetically linked in five of eight mutants, and the DNA flanking the insertions was characterized. For the strains with altered growth at 37°C and altered melanin production, mutations were in previously uncharacterized genes, while the two NO-sensitive strains bore insertions in the flavohemoglobin gene FHB1 , whose product counters NO stress. Because of the frequent instability of nourseothricin resistance associated with biolistic transformation, Agrobacterium -mediated transformation was tested. This transkingdom DNA delivery approach produced 100% stable nourseothricin-resistant transformants, and three melanin-defective strains were identified from 576 transformants, of which 2 were linked to NAT in segregation analysis. One of these mutants contained a T-DNA insertion in the promoter of the LAC1 (laccase) gene, which encodes a key enzyme required for melanin production, while the second contained an insertion in the promoter of the CLC1 gene, encoding a voltage-gated chloride channel. Clc1 and its homologs are required for ion homeostasis, and in their absence Cu + transport into the secretory pathway is compromised, depriving laccase and other Cu + -dependent proteins of their essential cofactor. The NAT resistance cassette was optimized for cryptococcal codon usage and GC content and was then used to disrupt a mitogen-activated protein kinase gene, a predicted gene, and two putative chloride channel genes to analyze their contributions to fungal physiology. Our findings demonstrate that both insertional mutagenesis methods can be applied to gene identification, but Agrobacterium -mediated transformation is more efficient and generates exclusively stable insertion mutations.
Amblypygid-fungal interactions: The whip spider exoskeleton as a substrate for fungal growth
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.FUNBIO.2019.05.003
Abstract: Fungi and arthropods represent some of the most erse organisms on our planet, yet the ecological relationships between them remain largely unknown. In animals, fungal growth on body surfaces is often hazardous and is known to cause mortality. In contrast, here we report the presence of an apparently non-harmful mycobiome on the cuticle of whip spiders (Arachnida: Amblypygi). The associations are not species-specific and involve a ersity of fungal species, including cosmopolitan and local decomposers as well as entomopathogens. We discuss the ecology of the detected fungal species and hypothesize that the thick epicuticular secretion coat of whip spiders (the cerotegument) promotes fungal growth. It is possible that this relationship is beneficial towards the host if it leads to parasite control or chemical camouflage. Our findings, which are the first from this arthropod lineage, indicate that non-pathogenic interactions between arthropods and fungi may be much more widespread than predicted and call for more studies in this area.
A new family of structurally conserved fungal effectors displays epistatic interactions with plant resistance proteins
Publisher: Cold Spring Harbor Laboratory
Date: 17-12-2020
DOI: 10.1101/2020.12.17.423041
Abstract: Recognition of a pathogen avirulence (AVR) effector protein by a cognate plant resistance (R) protein triggers a set of immune responses that render the plant resistant. Pathogens can escape this so-called Effector-Triggered Immunity (ETI) by different mechanisms including the deletion or loss-of-function mutation of the AVR gene, the incorporation of point mutations that allow recognition to be evaded while maintaining virulence function, and the acquisition of new effectors that suppress AVR recognition. The Dothideomycete Leptosphaeria maculans , causal agent of oilseed rape stem canker, is one of the few fungal pathogens where suppression of ETI by an AVR effector has been demonstrated. Indeed, AvrLm4-7 suppresses Rlm3- and Rlm9- mediated resistance triggered by AvrLm3 and AvrLm5-9, respectively. The presence of AvrLm4-7 does not impede AvrLm3 and AvrLm5-9 expression, and the three AVR proteins do not appear to physically interact. To decipher the epistatic interaction between these L. maculans AVR effectors, we determined the crystal structure of AvrLm5-9 and obtained a 3D model of AvrLm3, based on the crystal structure of Ecp11-1, a homologous AVR effector candidate from Fulvia fulva . Despite a lack of sequence similarity, AvrLm5-9 and AvrLm3 are structural analogues of AvrLm4-7 (structure previously characterized). Structure-informed sequence database searches identified a larger number of putative structural analogues among L. maculans effector candidates, including the AVR effector AvrLmS-Lep2, all produced during the early stages of oilseed rape infection, as well as among effector candidates from other phytopathogenic fungi. These structural analogues are named LARS (for Leptosphaeria AviRulence and Suppressing) effectors. Remarkably, transformants of L. maculans expressing one of these structural analogues, Ecp11-1, triggered oilseed rape immunity in several genotypes carrying Rlm3 . Furthermore, this resistance could be suppressed by AvrLm4-7. These results suggest that Ecp11-1 shares a common activity with AvrLm3 within the host plant which is detected by Rlm3, or that the Ecp11-1 structure is sufficiently close to that of AvrLm3 to be recognized by Rlm3. An efficient strategy to control fungal diseases in the field is genetic control using resistant crop cultivars. Crop resistance mainly relies on gene-for-gene relationships between plant resistance ( R ) genes and pathogen avirulence ( AVR ) genes, as defined by Flor in the 1940s. However, such gene-for-gene relationships can increase in complexity over the course of plant-pathogen co-evolution. Resistance against the plant-pathogenic fungus Leptosphaeria maculans by Brassica napus and other Brassica species relies on the recognition of effector (AVR) proteins by R proteins however, L. maculans produces an effector that suppresses a subset of these specific resistances. Using a protein structure approach, we revealed structural analogy between several of the resistance-triggering effectors, the resistance-suppressing effector, and effectors from other plant-pathogenic species in the Dothideomycetes and Sordariomycetes classes, defining a new family of effectors called LARS. Notably, cross-species expression of one LARS effector from Fulvia fulva , a pathogen of tomato, in L. maculans resulted in recognition by several resistant cultivars of oilseed rape. These results highlight the need to integrate knowledge on effector structures to improve resistance management and to develop broad-spectrum resistances for multi-pathogen control of diseases.
Two origins for the gene encoding α-isopropylmalate synthase in fungi
Publisher: Public Library of Science (PLoS)
Date: 15-07-2010
Pilaira australis sp. nov. (mucorales, mucoromycota) isolated from emu faeces in Australia
Publisher: Magnolia Press
Date: 12-2017
DOI: 10.11646/PHYTOTAXA.329.3.9
Abstract: Pilaira australis, a new species of fungus in the coprophilous genus Pilaira, was isolated from emu (Dromaius novaehollandiae) faeces and is described. Morphologically, the species resembles other species in the genus, particularly P. moreaui, except differs in its unique combination of sporangiophore height and sporangiospore length. Molecular phylogenetic analysis indicates that P. australis is distinct from other species in the genus with two regions, the internal transcribed spacers (ITS) and a fragment of the pyrG gene, showing 91% and 90% identity to the nearest species, respectively. Ultrastructure features and carbon utilisation were determined for P. australis, and may provide characteristics for species identification in this genus.
Analysis of the Genome and Transcriptome of Cryptococcus neoformans var. grubii Reveals Complex RNA Expression and Microevolution Leading to Virulence Attenuation
Publisher: Public Library of Science (PLoS)
Date: 17-04-2014
Fungal physiology: Red light plugs into MAPK pathway.
Publisher: Springer Science and Business Media LLC
Date: 26-04-2016
Congenic strains of the filamentous form of Cryptococcus neoformans for studies of fungal morphogenesis and virulence
Publisher: American Society for Microbiology
Date: 07-2013
DOI: 10.1128/IAI.00259-13
Abstract: Cryptococcus neoformans is an unconventional dimorphic fungus that can grow either as a yeast or in a filamentous form. To facilitate investigation of genetic factors important for its morphogenesis and pathogenicity, congenic a and α strains for a filamentous form were constructed. XL280 (α) was selected as the background strain because of its robust ability to undergo the morphological transition from yeast to the filamentous form. The MAT a allele from a sequenced strain JEC20 was introgressed into the XL280 background to generate the congenic a and α pair strains. The resulting congenic strains were then used to test the impact of mating type on virulence. In both the inhalation and the intravenous infection models of murine cryptococcosis, the congenic a and α strains displayed comparable levels of high virulence. The a -α coinfections displayed equivalent virulence to the in idual a or α infections in both animal models. Further analyses of the mating type distribution in a -α coinfected mice suggested no influence of a -α interactions on cryptococcal neurotropism, irrespective of the route of inoculation. Furthermore, deletion or overexpression of a known transcription factor, Znf2, in XL280 abolished or enhanced filamentation and biofilm formation, consistent with its established role. Overexpression of Znf2 in XL280 led to attenuation of virulence and a reduced abundance in the brain but not in other organs, suggesting that Znf2 might interfere with cryptococcal neurotropism upon extrapulmonary dissemination. In summary, the congenic strains provide a new resource for the exploration of the relationship in Cryptococcus between cellular morphology and pathogenesis.
The CRISPR revolution in fungal biology and biotechnology, and beyond
Publisher: Springer Science and Business Media LLC
Date: 12-2018
Genomic and genetic insights into a cosmopolitan fungus, paecilomyces variotii (Eurotiales)
Publisher: Frontiers Media SA
Date: 13-12-2018
Rising to the challenge of multiple Cryptococcus species and the diseases they cause.
Publisher: Elsevier BV
Date: 05-2015
A New Genetic Linkage Map of the Zygomycete Fungus Phycomyces blakesleeanus
Publisher: No publisher found
Date: 2013
Identification of ENA1 as a virulence gene of the human pathogenic fungus Cryptococcus neoformans through signature-tagged insertional mutagenesis
Publisher: American Society for Microbiology
Date: 03-2009
DOI: 10.1128/EC.00375-08
Abstract: A library of more than 4,500 signature-tagged insertion mutants of the human pathogenic fungus Cryptococcus neoformans was generated, and a subset was screened in a murine inhalation model to identify genes required for virulence. New genes that regulate aspects of C. neoformans virulence were also identified by screening the entire library for in vitro phenotypes related to the ability to cause disease, including melanin production, growth at high temperature, and growth under conditions of nutrient limitation. A screen of 10% of the strain collection in mice identified an avirulent mutant strain with an insertion in the ENA1 gene, which is predicted to encode a fungus-specific sodium or potassium P-type ATPase. The results of the deletion of the gene and complementation experiments confirmed its key role in mammalian virulence. ena1 mutant strains exhibited no change in sensitivity to high salt concentrations but were sensitive to alkaline pH conditions, providing evidence that the fungus may have to survive at elevated pH during infection of the mammalian host. The mutation of the well-characterized virulence factor calcineurin ( CNA1 ) also rendered C. neoformans strains sensitive to elevated pH. ENA1 transcripts in wild-type and cna1 mutant strains were upregulated in response to high pH, and cna1 ena1 double mutant strains exhibited increased sensitivity to elevated pH, indicating that at least two pathways in the fungus mediate survival under alkaline conditions. Signature-tagged mutagenesis is an effective strategy for the discovery of new virulence genes in fungal pathogens of animals.
Genetic characterisation and taxonomy of species of Anisakis (Nematoda:Anisakidae) parasitic in Australian marine mammals
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/IS11019
Abstract: Three species of Anisakis from Australian marine mammals, including Anisakis brevispiculata, A. simplex C and A. pegreffii, are described and characterised genetically on the basis of sequence data for the first and second internal transcribed spacers (ITS-1 and ITS-2) of nuclear rDNA. Parasite specimens were collected from Delphinus delphis, Tursiops truntatus and Kogia sima in Australia. A. brevispiculata is reported for the first time in Australia. However, analyses of sequence data suggests that A. brevispiculata in Australia is genetically distinct from specimens considered to represent the same species from other parts of the world. Fourth larval and adult stages of A. pegreffii were found in dolphins. Assigning larvae to A. pegreffii was based on the ITS-1 and ITS-2 sequences. A description of these larvae also is provided. Furthermore, fourth-stage larvae of A. simplex C were found in Kogia sima. Alignments of ITS-1 and ITS-2 sequences for members of A. simplex sensu lato revealed that nucleotide differences in ITS-1 can be used to differentiate among members of A. simplex sensu lato. This study reinforces the use of a combined molecular and morphological approach for the specific identification of anisakid nematodes.
‘Division of labour’ in response to host oxidative burst drives a fatal Cryptococcus gattii outbreak
Publisher: Springer Science and Business Media LLC
Date: 17-10-2014
DOI: 10.1038/NCOMMS6194
Abstract: Cryptococcus gattii is an emerging intracellular pathogen and the cause of the largest primary outbreak of a life-threatening fungal disease in a healthy population. Outbreak strains share a unique mitochondrial gene expression profile and an increased ability to tubularize their mitochondria within host macrophages. However, the underlying mechanism that causes this lineage of C. gattii to be virulent in immunocompetent in iduals remains unexplained. Here we show that a subpopulation of intracellular C. gattii adopts a tubular mitochondrial morphology in response to host reactive oxygen species. These fungal cells then facilitate the rapid growth of neighbouring C. gattii cells with non-tubular mitochondria, allowing for effective establishment of the pathogen within a macrophage intracellular niche. Thus, host reactive oxygen species, an essential component of the innate immune response, act as major signalling molecules to trigger a ‘ ision of labour’ in the intracellular fungal population, leading to increased pathogenesis within this outbreak lineage.
Effects of chitin and chitosan on root growth, biochemical defense response and exudate proteome ofCannabis sativa
Publisher: Cold Spring Harbor Laboratory
Date: 28-10-2022
DOI: 10.1101/2022.10.27.514128
Abstract: Fungal pathogens pose a major threat to Cannabis sativa production, requiring safe and effective management procedures to control disease. Chitin and chitosan are natural molecules that elicit plant defense responses. Investigation of their effects on C. sativa will advance understanding of plant responses towards elicitors and provide a potential pathway to enhance plant resistance against diseases. Plants were grown in the in vitro Root-TRAPR system and treated with colloidal chitin and chitosan. Plant morphology was monitored, then plant tissues and exudates were collected for enzymatic activity assays, phytohormone quantification, qPCR analysis and proteomics profiling. Chitosan treatments showed increased total chitinase activity and expression of pathogenesis-related (PR) genes by 3-5 times in the root tissues. In the exudates, total peroxidase and chitinase activities and levels of defense proteins such as PR protein 1 and endochitinase 2 were increased. Shoot development was unaffected, but root development was inhibited after chitosan exposure. No significant effects on plant defense were observed upon chitin treatment. These results indicate that colloidal chitosan significantly promoted production and secretion of plant defense proteins in C. sativa root system and could be used as a potential elicitor, particularly in hydroponic scenarios to manage crop diseases. Chitosan induces defense protein productions and secretions in the root tissues and exudates of C. sativa , offering a potential pathway to enhance plant resistance against fungal attack.
Constitutive expression of transcription factor SirZ blocks pathogenicity in Leptosphaeria maculans independently of sirodesmin production
Publisher: Public Library of Science (PLoS)
Date: 10-06-2021
DOI: 10.1371/JOURNAL.PONE.0252333
Abstract: Sirodesmin, the major secondary metabolite produced by the plant pathogenic fungus Leptosphaeria maculans in vitro, has been linked to disease on Brassica species since the 1970s, and yet its role has remained ambiguous. Re-examination of gene expression data revealed that all previously described genes and two newly identified genes within the sir gene cluster in the genome are down-regulated during the crucial early establishment stages of blackleg disease on Brassica napus . To test if this is a strategy employed by the fungus to avoid damage to and then detection by the host plant during the L . maculans asymptomatic biotrophic phase, sirodesmin was produced constitutively by overexpressing the sirZ gene encoding the transcription factor that coordinates the regulation of the other genes in the sir cluster. The sirZ over-expression strains had a major reduction in pathogenicity. Mutation of the over-expression construct restored pathogenicity. However, mutation of two genes, sirP and sirG , required for specific steps in the sirodesmin biosynthesis pathway, in the sirZ over-expression background resulted in strains that were unable to synthesize sirodesmin, yet were still non-pathogenic. Elucidating the basis for this pathogenicity defect or finding ways to overexpress sirZ during disease may provide new strategies for the control of blackleg disease.
Isocitrate lyase is essential for pathogenicity of the fungus Leptosphaeria maculans to canola (Brassica napus)
Publisher: American Society for Microbiology
Date: 10-2002
DOI: 10.1128/EC.1.5.719-724.2002
Abstract: A pathogenicity gene has been identified in Leptosphaeria maculans , the ascomycetous fungus that causes blackleg disease of canola ( Brassica napus) . This gene encodes isocitrate lyase, a component of the glyoxylate cycle, and is essential for the successful colonization of B. napus . It was identified by a reverse genetics approach whereby a plasmid conferring hygromycin resistance was inserted randomly into the L. maculans genome. Twelve of 516 transformants tested had reduced pathogenicity on cotyledons of B. juncea and B. napus , and 1 of these 12 had a deletion of the isocitrate lyase gene, as well as an insertion of the hygromycin resistance gene. This mutant was unable to grow on fatty acids, including monolaurate, and the isocitrate lyase transcript was not detected. When the wild-type gene was reintroduced into the mutant, growth on monolaurate was restored and pathogenicity was partially restored. L. maculans isocitrate lyase is produced during infection of B. napus cotyledons, while the plant homologue is not. When 2.5% glucose was added to the inoculum of the isocitrate lyase mutant, lesions of sizes similar to those caused by wild-type isolate M1 developed on B. napus cotyledons. These findings suggest that the glyoxylate pathway is essential for disease development by this plant-pathogenic fungus, as has been shown recently for a fungal and bacterial pathogen of animals and a bacterial pathogen of plants. Involvement of the glyoxylate pathway in pathogenesis in animals and plants presents potential drug targets for control of diseases.
Characterisation of neutral trehalase and UDP-glucose:sterol glucosyltransferase genes from the plant pathogenic fungus Leptosphaeria maculans
Publisher: Elsevier BV
Date: 05-2003
Fungal Pathogenesis: Gene Clusters Unveiled as Secrets within the Ustilago maydis Code
Publisher: Elsevier BV
Date: 02-2007
DOI: 10.1016/J.CUB.2006.11.047
Abstract: The genome sequence of a second plant pathogenic fungus is now available, revealing unique gene clusters encoding secretory proteins that are induced during infection and regulate pathogenesis. Gene clusters play important roles in pathogenic fungi, yet their evolution and maintenance remain a mystery.
Diversity, ecology, and evolution in Phycomyces
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.FUNBIO.2015.07.005
Abstract: The fungal genus Phycomyces (Mucoromycotina, Mucorales) has been revised by examining 96 strains, received from established collections or newly isolated from different environments. Morphology, sexuality, DNA sequences, and population structure clearly identify the genus and set it apart from other Mucorales. The size of the spores, the sexual interactions, the sequences of genes sexM and sexP that determine sexual identity, and the DNA for ribosomal RNAs validate the species Phycomyces blakesleeanus and Phycomyces nitens and the family Phycomycetaceae. Isolates from the same s le of biomass often differ in spore size, sex, DNA sequences, and restriction-length polymorphisms. The widest ersity was found in similar environments in three of the Canary Islands, implying a failure to disperse rapidly over the sea. All strains have apparently functional sexM and sexP genes and all but some strains of P. nitens complete the sexual cycle in the laboratory. The genetic ersity of P. blakesleeanus strains provides evidence for geographical clustering. Various sequence comparisons, including the newly isolated genes sexM and sexP of P. nitens and Blakeslea trispora, clarify phylogenetic relationships in the Mucorales and recommend the sex genes for the study of speciation.
Effects of chitin and chitosan on root growth, biochemical defense response and exudate proteome of Cannabis sativa
Publisher: Wiley
Date: 02-04-2023
DOI: 10.1002/PEI3.10106
Abstract: Fungal pathogens pose a major threat to Cannabis sativa production, requiring safe and effective management procedures to control disease. Chitin and chitosan are natural molecules that elicit plant defense responses. Investigation of their effects on C. sativa will advance understanding of plant responses towards elicitors and provide a potential pathway to enhance plant resistance against diseases. Plants were grown in the in vitro Root‐TRAPR system and treated with colloidal chitin and chitosan. Plant morphology was monitored, then plant tissues and exudates were collected for enzymatic activity assays, phytohormone quantification, qPCR analysis and proteomics profiling. Chitosan treatments showed increased total chitinase activity and expression of pathogenesis‐related (PR) genes by 3–5 times in the root tissues. In the exudates, total peroxidase and chitinase activities and levels of defense proteins such as PR protein 1 and endochitinase 2 were increased. Shoot development was unaffected, but root development was inhibited after chitosan exposure. In contrast, chitin treatments had no significant impact on any defense parameters, including enzymatic activities, hormone quantities, gene expression levels and root secreted proteins. These results indicate that colloidal chitosan, significantly enhancing defense responses in C. sativa root system, could be used as a potential elicitor, particularly in hydroponic scenarios to manage crop diseases.
The TOR Pathway Plays Pleiotropic Roles in Growth and Stress Responses of the Fungal Pathogen Cryptococcus neoformans
Publisher: Oxford University Press (OUP)
Date: 07-06-2019
DOI: 10.1534/GENETICS.119.302191
Abstract: The target of rapamycin (TOR) pathway is an evolutionarily conserved signal transduction system that governs a plethora of eukaryotic biological processes, but its role in Cryptococcus neoformans remains elusive. In this study, we investigated the TOR pathway by functionally characterizing two Tor-like kinases, Tor1 and Tlk1, in C. neoformans. We successfully deleted TLK1, but not TOR1. TLK1 deletion did not result in any evident in vitro phenotypes, suggesting that Tlk1 is dispensable for the growth of C. neoformans. We demonstrated that Tor1, but not Tlk1, is essential and the target of rapamycin by constructing and analyzing conditionally regulated strains and sporulation analysis of heterozygous mutants in the diploid strain background. To further analyze the Tor1 function, we constructed constitutive TOR1 overexpression strains. Tor1 negatively regulated thermotolerance and the DNA damage response, which are two important virulence factors of C. neoformans. TOR1 overexpression reduced Mpk1 phosphorylation, which is required for cell wall integrity and thermoresistance, and Rad53 phosphorylation, which governs the DNA damage response pathway. Tor1 is localized to the cytoplasm, but enriched in the vacuole membrane. Phosphoproteomics and transcriptomics revealed that Tor1 regulates a variety of biological processes, including metabolic processes, cytoskeleton organization, ribosome biogenesis, and stress response. TOR inhibition by rapamycin caused actin depolarization in a Tor1-dependent manner. Finally, screening rapamycin-sensitive and -resistant kinase and transcription factor mutants revealed that the TOR pathway may crosstalk with a number of stress signaling pathways. In conclusion, our study demonstrates that a single Tor1 kinase plays pleiotropic roles in C. neoformans.
Expansion of Signal Transduction Pathways in Fungi by Extensive Genome Duplication
Publisher: Elsevier BV
Date: 06-2016
Peroxisome Function Regulates Growth on Glucose in the Basidiomycete Fungus Cryptococcus neoformans
Publisher: American Society for Microbiology
Date: 2007
DOI: 10.1128/EC.00214-06
Abstract: The function of the peroxisomes was examined in the pathogenic basidiomycete Cryptococcus neoformans . Recent studies reveal the glyoxylate pathway is required for virulence of erse microbial pathogens of plants and animals. One exception is C. neoformans , in which isocitrate lyase (encoded by ICL1 ) was previously shown not to be required for virulence, and here this was extended to exclude also a role for malate synthase (encoded by MLS1 ). The role of peroxisomes, in which the glyoxylate pathway enzymes are localized in many organisms, was examined by mutation of two genes ( PEX1 and PEX6 ) encoding AAA ( A TPases a ssociated with various cellular a ctivities)-type proteins required for peroxisome formation. The pex1 and pex6 deletion mutants were unable to localize the fluorescent DsRED-SKL protein to peroxisomal punctate structures, in contrast to wild-type cells. pex1 and pex6 single mutants and a pex1 pex6 double mutant exhibit identical phenotypes, including abolished growth on fatty acids but no growth difference on acetate. Because both icl1 and mls1 mutants are unable to grow on acetate as the sole carbon source, these findings demonstrate that the glyoxylate pathway can function efficiently outside the peroxisome in C. neoformans . The pex1 mutant exhibits wild-type virulence in a murine inhalation model and in an insect host, demonstrating that peroxisomes are not required for virulence under these conditions. An unusual phenotype of the pex1 and pex6 mutants was that they grew poorly with glucose as the carbon source, but nearly wild type with galactose, which suggested impaired hexokinase function and that C. neoformans peroxisomes might function analogously to the glycosomes of the trypanosomid parasites. Deletion of the hexokinase HXK2 gene reduced growth in the presence of glucose and suppressed the growth defect of the pex1 mutant on glucose. The hexokinase 2 protein of C. neoformans contains a predicted peroxisome targeting signal (type 2) motif however, Hxk2 fused to fluorescent proteins was not localized to peroxisomes. Thus, we hypothesize that glucose or glycolytic metabolites are utilized in the peroxisome by an as yet unidentified enzyme or regulate a pathway required by the fungus in the absence of peroxisomes.
Fungal sex: The mucoromycota
Publisher: American Society for Microbiology
Date: 10-03-2017
DOI: 10.1128/MICROBIOLSPEC.FUNK-0041-2017
Abstract: Although at the level of resolution of genes and molecules most information about mating in fungi is from a single lineage, the Dikarya, many fundamental discoveries about mating in fungi have been made in the earlier branches of the fungi. These are nonmonophyletic groups that were once classified into the chytrids and zygomycetes. Few species in these lineages offer the potential of genetic tractability, thereby h ering the ability to identify the genes that underlie those fundamental insights. Research performed during the past decade has now established the genes required for mating type determination and pheromone synthesis in some species in the phylum Mucoromycota, especially in the order Mucorales. These findings provide striking parallels with the evolution of mating systems in the Dikarya fungi. Other discoveries in the Mucorales provide the first ex les of sex-cell type identity being driven directly by a gene that confers mating type, a trait considered more of relevance to animal sex determination but difficult to investigate in animals. Despite these discoveries, there remains much to be gleaned about mating systems from these fungi.
A silver bullet in a golden age of functional genomics: the impact of Agrobacterium-mediated transformation of fungi
Publisher: Springer Science and Business Media LLC
Date: 26-09-2017
Sex determination directs uniparental mitochondrial inheritance in Phycomyces
Publisher: American Society for Microbiology
Date: 02-2014
DOI: 10.1128/EC.00203-13
Abstract: Uniparental inheritance (UPI) of mitochondria is common among eukaryotes. The underlying molecular basis by which the sexes of the parents control this non-Mendelian pattern of inheritance is yet to be fully understood. Two major factors have complicated the understanding of the role of sex-specific genes in the UPI phenomenon: in many cases (i) fusion occurs between cells of unequal size or (ii) mating requires a large region of the genome or chromosome that includes genes unrelated to sex determination. The fungus Phycomyces blakesleeanus is a member of the Mucoromycotina and has a simple mating type locus encoding only one high-mobility group (HMG) domain protein, and mating occurs by fusion of isogamous cells, thus providing a model system without the limitations mentioned above. Analysis of more than 250 progeny from a series of genetic crosses between wild-type strains of Phycomyces revealed a correlation between the in idual genes in the mating type locus and UPI of mitochondria. Inheritance is from the plus (+) sex type and is associated with degradation of the mtDNA from the minus (−) parent. These findings suggest that UPI can be directly controlled by genes that determine sex identity, independent of cell size or the complexity of the genetic composition of a sex chromosome.
Characterization of an opsin gene from the ascomycete Leptosphaeria maculans
Publisher: Canadian Science Publishing
Date: 2001
DOI: 10.1139/GEN-44-2-167
Biotechnological potential of engineering pathogen effector proteins for use in plant disease management
Publisher: Elsevier BV
Date: 11-2019
DOI: 10.1016/J.BIOTECHADV.2019.04.009
Abstract: A key component in the management of many diseases of crops is the use of plant disease resistance genes. However, the discovery and then sequence identification of these plant genes is challenging, whereas the characterization of the molecules that they recognize, the effector/avirulence products in pathogens, is often considerably more straight forward. Effectors are small proteins secreted by pathogens that can play major roles in modulating a plant's defense against attack. Effectors can be used to guide breeding of resistance genes, to trigger defense responses, and are part of integrated disease management strategies for crop protection. This review covers the role of effector-driven biotechnology in controlling plant diseases caused by fungi or oomycetes. Given that multi-billion dollar agriculture crops are based in some cases on plants recognizing just a handful of such effector proteins, there is considerable scope to use more fully effector proteins as a biotechnology resource in agriculture.
Starships are active eukaryotic transposable elements mobilized by a new family of tyrosine recombinases
Publisher: Proceedings of the National Academy of Sciences
Date: 06-04-2023
Abstract: Transposable elements in eukaryotic organisms have historically been considered “selfish,” at best conferring indirect benefits to their host organisms. The Starships are a recently discovered feature in fungal genomes that are, in some cases, predicted to confer beneficial traits to their hosts and also have hallmarks of being transposable elements. Here, we provide experimental evidence that Starships are indeed autonomous transposons, using the model Paecilomyces variotii , and identify the HhpA “Captain” tyrosine recombinase as essential for their mobilization into genomic sites with a specific target site consensus sequence. Furthermore, we identify multiple recent horizontal gene transfers of Starships , implying that they jump between species. Fungal genomes have mechanisms to defend against mobile elements, which are frequently detrimental to the host. We discover that Starships are also vulnerable to repeat-induced point mutation defense, thereby having implications on the evolutionary stability of such elements.
Searching for genes responsible for patulin degradation in a biocontrol yeast provides insight into the basis for resistance to this mycotoxin
Publisher: American Society for Microbiology
Date: 05-2013
DOI: 10.1128/AEM.03851-12
Abstract: Patulin is a mycotoxin that contaminates pome fruits and derived products worldwide. Basidiomycete yeasts belonging to the subphylum Pucciniomycotina have been identified to have the ability to degrade this molecule efficiently and have been explored through different approaches to understand this degradation process. In this study, Sporobolomyces sp. strain IAM 13481 was found to be able to degrade patulin to form two different breakdown products, desoxypatulinic acid and ( Z ) - ascladiol. To gain insight into the genetic basis of tolerance and degradation of patulin, more than 3,000 transfer DNA (T-DNA) insertional mutants were generated in strain IAM 13481 and screened for the inability to degrade patulin using a bioassay based on the sensitivity of Escherichia coli to patulin. Thirteen mutants showing reduced growth in the presence of patulin were isolated and further characterized. Genes disrupted in patulin-sensitive mutants included homologs of Saccharomyces cerevisiae YCK2 , PAC2 , DAL5 , and VPS8 . The patulin-sensitive mutants also exhibited hypersensitivity to reactive oxygen species as well as genotoxic and cell wall-destabilizing agents, suggesting that the inactivated genes are essential for tolerating and overcoming the initial toxicity of patulin. These results support a model whereby patulin degradation occurs through a multistep process that includes an initial tolerance to patulin that utilizes processes common to other external stresses, followed by two separate pathways for degradation.
Photosensing fungi: Phytochrome in the spotlight
Publisher: Elsevier BV
Date: 10-2005
DOI: 10.1016/J.CUB.2005.10.001
Abstract: Red light triggers asexual development and represses sexual development in the fungus Aspergillus nidulans. This response has been shown to require a phytochrome red/far-red light photoreceptor, FphA, which is cytoplasmic and binds a tetrapyrrole chromophore. FphA exhibits similarities to both plant and bacterial phytochromes.
A Polyphasic Approach including Whole Genome Sequencing Reveals Paecilomyces paravariotii sp. nov. as a Cryptic Sister Species to P. variotii
Publisher: MDPI AG
Date: 22-02-2023
DOI: 10.3390/JOF9030285
Abstract: Whole genome sequencing is rapidly increasing phylogenetic resolution across many groups of fungi. To improve sequencing coverage in the genus Paecilomyces (Eurotiales), we report nine new Paecilomyces genomes representing five different species. Phylogenetic comparison between these genomes and those reported previously showed that Paecilomyces paravariotii is a distinct species from its close relative P. variotii. The independence of P. paravariotii is supported by analysis of overall gene identify (via BLAST), differences in secondary metabolism and an inability to form ascomata when paired with a fertile P. variotii strain of opposite mating type. Furthermore, whole genome sequencing resolves the P. formosus clade into three separate species, one of which lacked a valid name that is now provided.
Enhanced proliferation of pancreatic acinar cells in MRL/MpJ mice is driven by severe acinar injury but independent of inflammation
Publisher: Springer Science and Business Media LLC
Date: 20-06-2018
DOI: 10.1038/S41598-018-27422-0
Abstract: Adult pancreatic acinar cells have the ability to re-enter the cell cycle and proliferate upon injury or tissue loss. Despite this mitotic ability, the extent of acinar proliferation is often limited and unable to completely regenerate the injured tissue or restore the initial volume of the organ, thus leading to pancreatic dysfunction. Identifying molecular determinants of enhanced proliferation is critical to overcome this issue. In this study, we discovered that Murphy Roths Large (MRL/MpJ) mice can be exploited to identify molecular effectors promoting acinar proliferation upon injury, with the ultimate goal to develop therapeutic regimens to boost pancreatic regeneration. Our results show that, upon cerulein-induced acinar injury, cell proliferation was enhanced and cell cycle components up-regulated in the pancreas of MRL/MpJ mice compared to the control strain C57BL/6. Initial damage of acinar cells was exacerbated in these mice, manifested by increased serum levels of pancreatic enzymes, intra-pancreatic trypsinogen activation and acinar cell apoptosis. In addition, MRL/MpJ pancreata presented enhanced inflammation, de-differentiation of acinar cells and acinar-to-ductal metaplasia. Manipulation of inflammatory levels and mitogenic stimulation with the thyroid hormone 5,3-L-tri-iodothyronine revealed that factors derived from initial acinar injury rather than inflammatory injury promote the replicative advantage in MRL/MpJ mice.
Sit4-Associated Protein is Required for Pathogenicity of Leptosphaeria maculans on Brassica napus
Publisher: Springer Science and Business Media LLC
Date: 24-08-2017
DOI: 10.1007/S00284-017-1338-3
Abstract: An insertional mutant with reduced pathogenicity on Brassica napus was identified in the plant pathogenic fungus Leptosphaeria maculans. The transfer-DNA molecule from Agrobacterium tumefaciens inserted into a gene encoding a protein with similarity to Sit4-associated proteins (SAPs). In contrast to Saccharomyces cerevisiae which has four members of the SAP family, there is a single copy of the gene in L. maculans. The mutant had normal spore production and spore germination, but altered hyphal branching, suggesting that nutrient signaling is impaired in the strain. This is the first time that a SAP gene has been mutated in a filamentous fungus and links the function of SAP proteins to plant pathogenesis and hyphal branching.
Phs1 and the Synthesis of Very Long Chain Fatty Acids Are Required for Ballistospore Formation
Publisher: Public Library of Science (PLoS)
Date: 22-08-2014
Physiology and genetics of self-incompatibility in Echinopsis chamaecereus (Cactaceae)
Publisher: Springer Science and Business Media LLC
Date: 07-2000
Fungal diseases of canola in Australia: identification of trends, threats and potential therapies
Publisher: Springer Science and Business Media LLC
Date: 02-07-2016
The dual function gene RAD23 contributes to Cryptococcus neoformans virulence independently of its role in nucleotide excision DNA repair
Publisher: Elsevier BV
Date: 10-2019
DOI: 10.1016/J.GENE.2019.144043
Abstract: Genes involved in the repair of DNA damage are emerging as playing important roles during the disease processes caused by pathogenic fungi. However, there are potentially hundreds of genes involved in DNA repair in a fungus and some of those genes can play additional roles within the cell. One such gene is RAD23, required for virulence of the human pathogenic fungus Cryptococcus neoformans, that encodes a protein involved in the nucleotide excision repair (NER) pathway. However, Rad23 is a dual function protein, with a role in either repair of damaged DNA or protein turn over by directing proteins to the proteasome. Here, these two functions of Rad23 were tested by the creation of a series of domain deletion alleles of RAD23 and the assessment of the strains for DNA repair, proteasome functions, and virulence properties. Deletion of the different domains was able to uncouple the two functions of Rad23, and the phenotypes of strains carrying such forms indicated that the role of RAD23 in virulence is due to its function in proteasomal-mediated protein degradation rather than NER.
Spontaneous and CRISPR/Cas9-induced mutation of the osmosensor histidine kinase of the canola pathogen Leptosphaeria maculans.
Publisher: Springer Science and Business Media LLC
Date: 12-2017
Mismatch repair of DNA replication errors contributes to microevolution in the pathogenic fungus Cryptococcus neoformans
Publisher: American Society for Microbiology
Date: 05-07-2017
Abstract: The ability to adapt to a changing environment provides a selective advantage to microorganisms. In the case of many pathogens, a large change in their environment occurs when they move from a natural setting to a setting within a human host and then during the course of disease development to various locations within that host. Two clinical isolates of the human fungal pathogen Cryptococcus neoformans were identified from a collection of environmental and clinical strains that exhibited a mutator phenotype, which is a phenotype which provides the ability to change rapidly due to the accumulation of DNA mutations at high frequency. Whole-genome analysis of these strains revealed mutations in MSH2 of the mismatch repair pathway, and complementation confirmed that these mutations are responsible for the mutator phenotype. Comparison of mutation frequencies in deletion strains of eight mismatch repair pathway genes in C. neoformans showed that the loss of three of them, MSH2 , MLH1 , and PMS1 , results in an increase in mutation rates. Increased mutation rates enable rapid microevolution to occur in these strains, generating phenotypic variations in traits associated with the ability to grow in vivo , in addition to allowing rapid generation of resistance to antifungal agents. Mutation of PMS1 reduced virulence, whereas mutation of MSH2 or MLH1 had no effect on the level of virulence. These findings thus support the hypothesis that this pathogenic fungus can take advantage of a mutator phenotype in order to cause disease but that it can do so only in specific pathways that lead to a mutator trait without a significant tradeoff in fitness. IMPORTANCE Fungi account for a large number of infections that are extremely difficult to treat superficial fungal infections affect approximately 1.7 billion (25%) of the general population worldwide, and systemic fungal diseases result in an unacceptably high mortality rate. How fungi adapt to their hosts is not fully understood. This research investigated the role of changes to DNA sequences in adaption to the host environment and the ability to cause disease in Cryptococcus neoformans , one of the world’s most common and most deadly fungal pathogens. The study results showed that microevolutionary rates are enhanced in either clinical isolates or in gene deletion strains with msh2 mutations. This gene has similar functions in regulating the rapid emergence of antifungal drug resistance in a distant fungal relative of C. neoformans , the pathogen Candida glabrata . Thus, microevolution resulting from enhanced mutation rates may be a common contributor to fungal pathogenesis.
Transgene Induced Co-Suppression during Vegetative Growth in Cryptococcus neoformans
Publisher: Public Library of Science (PLoS)
Date: 16-08-2012
Leptosphaeria maculans, the causal agent of blackleg disease of Brassicas
Publisher: Elsevier BV
Date: 06-2001
Importance of Resolving Fungal Nomenclature: the Case of Multiple Pathogenic Species in the Cryptococcus Genus
Publisher: American Society for Microbiology
Date: 30-08-2017
Abstract: Cryptococcosis is a major fungal disease caused by members of the Cryptococcus gattii and Cryptococcus neoformans species complexes. After more than 15 years of molecular genetic and phenotypic studies and much debate, a proposal for a taxonomic revision was made.
The fungal gene cluster for biosynthesis of the antibacterial agent viriditoxin
Publisher: Springer Science and Business Media LLC
Date: 07-2019
Extreme diversification of the mating type-high-mobility group (MATA-HMG) gene family in a plant-associated arbuscular mycorrhizal fungus
Publisher: Wiley
Date: 27-08-2014
DOI: 10.1111/NPH.12462
Abstract: Arbuscular mycorrhizal fungi ( AMF ) are important plant symbionts that have long been considered evolutionary anomalies because of their apparent long‐term lack of sexuality, but recent explorations of available DNA sequence have challenged this notion by revealing the presence of homologues of fungal mating type – high‐mobility group ( MATA ‐ HMG ) and core meiotic genes in these organisms. To obtain more insights into the sexual potential of AMF , homologues of MATA ‐ HMG s were sought in the transcriptome of three AMF isolates, and their functional and evolutionary trajectories were studied in genetically ergent strains of R hizophagus irregularis using conventional and quantitative PCR procedures. Our analyses revealed the presence of at least 76 homologues of MATA ‐ HMG s in R . irregularis isolates. None of these was found to be surrounded by genes generally found near other known fungal mating type loci, but here we report the presence of a 9‐kb‐long region in the AMF R . irregularis harbouring a total of four tandem‐repeated MATA ‐ HMG s a feature that highlights a potentially elevated intragenomic ersity in this AMF species. The present study provides intriguing insights into the genome evolution of R . irregularis , and represents a stepping stone for understanding the potential of these fungi to undergo cryptic sex.
Essential gene discovery in the basidiomycete Cryptococcus neoformans for antifungal drug target prioritization.
Publisher: American Society for Microbiology
Date: 05-2015
Abstract: Fungal diseases represent a major burden to health care globally. As with other pathogenic microbes, there is a limited number of agents suitable for use in treating fungal diseases, and resistance to these agents can develop rapidly. Cryptococcus neoformans is a basidiomycete fungus that causes cryptococcosis worldwide in both immunocompromised and healthy in iduals. As a basidiomycete, it erged from other common pathogenic or model ascomycete fungi more than 500 million years ago. Here, we report C. neoformans genes that are essential for viability as identified through forward and reverse genetic approaches, using an engineered diploid strain and genetic segregation after meiosis. The forward genetic approach generated random insertional mutants in the diploid strain, the induction of meiosis and sporulation, and selection for haploid cells with counterselection of the insertion event. More than 2,500 mutants were analyzed, and transfer DNA (T-DNA) insertions in several genes required for viability were identified. The genes include those encoding the thioredoxin reductase (Trr1), a ribosome assembly factor (Rsa4), an mRNA-capping component (Cet1), and others. For targeted gene replacement, the C. neoformans homologs of 35 genes required for viability in ascomycete fungi were disrupted, meiosis and sporulation were induced, and haploid progeny were evaluated for their ability to grow on selective media. Twenty-one (60%) were found to be required for viability in C. neoformans . These genes are involved in mitochondrial translation, ergosterol biosynthesis, and RNA-related functions. The heterozygous diploid mutants were evaluated for haploinsufficiency on a number of perturbing agents and drugs, revealing phenotypes due to the loss of one copy of an essential gene in C. neoformans . This study expands the knowledge of the essential genes in fungi using a basidiomycete as a model organism. Genes that have no mammalian homologs and are essential in both Cryptococcus and ascomycete human pathogens would be ideal for the development of antifungal drugs with broad-spectrum activity. IMPORTANCE Fungal infections are very common in humans but may be neglected due to misdiagnosis and inattention. Cryptococcus neoformans is a yeast that infects mainly immunocompromised people, causing high mortality rates in developing countries. The fungus infects the lungs, crosses the blood-brain barrier, and invades the cerebrospinal fluid, causing fatal meningitis. C. neoformans infections are treated with hotericin B, flucytosine, and azoles, all developed decades ago. However, problems with antifungal agents highlight the urgent need for more-effective drugs to treat C. neoformans and other invasive fungal infections. These issues include the negative side effects of hotericin B, the spontaneous resistance of C. neoformans to azoles, and the inefficacy of the echinocandin antifungals. In this study, we report the identification of C. neoformans essential genes as targets for the development of novel antifungals. Because of the level of evolutionary ergence between C. neoformans and the ascomycetes, a subset of these genes is likely essential in all fungi. Genes identified in this study represent an excellent starting point for the future development of new antifungals by pharmaceutical companies.
Overcoming recalcitrant transformation and gene manipulation in Pucciniomycotina yeasts
Publisher: Springer Science and Business Media LLC
Date: 14-11-2013
DOI: 10.1007/S00253-012-4561-7
Abstract: The red yeasts of the Pucciniomycotina have rarely been transformed with DNA molecules. Transformation methods were recently developed for a species of Sporobolomyces, based on selection using uracil auxotrophs and plasmids carrying the wild-type copies of the URA3 and URA5 genes. However, these plasmids were ineffective in the transformation of closely related species. Using the genome-sequenced strain of Rhodotorula graminis as a starting point, the URA3 and URA5 genes were cloned and tested for the transformation ability into different Pucciniomycotina species by biolistic and Agrobacterium-mediated transformations. Transformation success depended on the red yeast species and the origin of the URA3 or URA5 genes, which may be related to the high G + C DNA content found in several species. A new vector was generated to confer resistance to nourseothricin, using a native promoter from R. graminis and the naturally high G + C nourseothricin acetyltransferease gene. This provides a second selectable marker in these species. Targeted gene disruption was tested in Sporobolomyces sp. IAM 13481 using different lengths of homologous DNA with biolistic and Agrobacterium transformation methods. Both DNA delivery methods were effective for targeted replacement of a gene required for carotenoid pigment biosynthesis. The constructs also triggered transgene silencing. These developments open the way to identify and manipulate gene functions in a large group of basidiomycete fungi.
Conserved elements of the RAM signaling pathway establish cell polarity in the basidiomycete Cryptococcus neoformans in a divergent fashion from other fungi
Publisher: American Society for Cell Biology (ASCB)
Date: 09-2006
Abstract: In eukaryotes the complex processes of development, differentiation, and proliferation require carefully orchestrated changes in cellular morphology. Single-celled eukaryotes provide tractable models for the elucidation of signaling pathways involved in morphogenesis. Here we describe a pathway regulating cell polarization and separation in the human pathogenic fungus Cryptococcus neoformans. An insertional mutagenesis screen identified roles for the ARF1, CAP60, NDH1, KIC1, CBK1, SOG2, and TAO3 genes in establishing normal colony morphology. ARF1 and CAP60 are also required for capsule production, a virulence factor, and ARF1 confers resistance to the antifungal fluconazole. KIC1, CBK1, SOG2, and TAO3 are homologues of genes conserved in other eukaryotes in Saccharomyces cerevisiae they constitute components of the RAM (regulation of Ace2p activity and cellular morphogenesis) signaling pathway. A targeted deletion of a fifth component of RAM (MOB2) conferred identical phenotypes to kic1, cbk1, sog2, or tao3 mutations. Characterization of these genes in C. neoformans revealed unique features of the RAM pathway in this organism. Loss of any of these genes caused constitutive hyperpolarization instead of the loss of polarity seen in S. cerevisiae. Furthermore, sensitivity to the drugs FK506 and cyclosporin A demonstrates that the RAM pathway acts in parallel with the protein phosphatase calcineurin in C. neoformans but not in S. cerevisiae. These results indicate that conserved signaling pathways serve both similar and ergent cellular roles in morphogenesis in these ergent organisms.
Cryptococcus neoformans Kin1 protein kinase homologue, identified through a Caenorhabditis elegans screen, promotes virulence in mammals
Publisher: Wiley
Date: 06-09-2004
DOI: 10.1111/J.1365-2958.2004.04310.X
Abstract: Cryptococcal infections are a global cause of significant morbidity and mortality. Recent studies support the hypothesis that virulence of Cryptococcus neoformans may have evolved via survival selection in environmental hosts, such as amoebae and free-living nematodes. We used killing of the nematode Caenorhabditis elegans by C. neoformans as an assay to screen a library of random C. neoformans insertion mutants. Of 350 mutants tested, seven were identified with attenuated virulence that persisted after crossing the mutation back into a wild-type strain. Genetic analysis of one strain revealed an insertion in a gene homologous to Saccharomyces cerevisiae KIN1, which encodes a serine/threonine protein kinase. C. neoformans kin1 mutants exhibited significant defects in virulence in murine inhalation and haematogenous infection models and displayed increased binding to alveolar and peritoneal macrophages. The kin1 mutant phenotypes were complemented by the wild-type KIN1 gene. These findings show that the C. neoformans Kin1 kinase homologue is required for full virulence in disparate hosts and that C. elegans can be used as a substitute host to identify novel factors involved in fungal pathogenesis in mammals.
The Third International Symposium on Fungal Stress – ISFUS
Publisher: Elsevier BV
Date: 05-2020
Isolation of conditional mutations in genes essential for viability of Cryptococcus neoformans
Publisher: Springer Science and Business Media LLC
Date: 25-10-2017
The inhibition of mating in Phycomyces blakesleeanus by light is dependent on the MadA-MadB complex that acts in a sex-specific manner
Publisher: Elsevier BV
Date: 04-2017
DOI: 10.1016/J.FGB.2017.02.005
Abstract: Light is an environmental signal that influences reproduction in the Mucoromycotina fungi, as it does in many other species of fungi. Mating in Phycomyces blakesleeanus is inhibited by light, but the molecular mechanisms for this inhibition are uncharacterized. In this analysis, the role of the light-sensing MadA-MadB complex in mating was tested. The MadA-MadB complex is homologous to the Neurospora crassa White Collar complex. Three genes required for cell type determination in the sex locus or pheromone biosynthesis are transcriptionally-regulated by light and are controlled by MadA and MadB. This regulation acts through the plus partner, indicating that the inhibitory effect of light on mating is executed through only one of the two sexes. These results are an ex le whereby the mating types of fungi have acquired sex-specific properties beyond their role in conferring cell-type identity, and provide insight into how sex-determining chromosomal regions can expand the traits they control.
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