ORCID Profile
0000-0002-2777-7448
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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)
Plant Cell and Molecular Biology | Crop and Pasture Biochemistry and Physiology | Plant Biology | Evolution of Developmental Systems | Plant Pathology | Plant Physiology | Medical Physiology | Systems Physiology | Systems Biology
ANZSRC Socio-Economic Objective (SEO)
Environmentally Sustainable Plant Production not elsewhere classified | Control of Animal Pests, Diseases and Exotic Species in Farmland, Arable Cropland and Permanent Cropland Environments | Winter Grains and Oilseeds not elsewhere classified | Rice | Wheat | Clinical Health (Organs, Diseases and Abnormal Conditions) not elsewhere classified | Environment not elsewhere classified | Expanding Knowledge in the Biological Sciences |
Related Links
Publications
Target genes for OBP3, a Dof transcription factor, include novel basic helix‐loop‐helix domain proteins inducible by salicylic acid
Publisher: Wiley
Date: 17-07-2003
DOI: 10.1046/J.1365-313X.2003.01812.X
Abstract: Overexpression of a salicylic-acid (SA)-inducible Arabidopsis DNA binding with one finger (Dof) transcription factor, called OBF-binding protein 3 (OBP3 AtDof3.6), has previously been shown to result in growth defects. In this study, suppressive subtraction hybridization (SSH) was used to isolate genes induced in an OBP3-overexpression line and several putative clones, called OBP3-responsive genes (ORGs), were isolated. The link with the induced expression levels of these genes and OBP3 overexpression was confirmed by analysing additional OBP3-overexpression lines. ORG1 through ORG4 are novel genes, while ORG5 is an extensin gene, AtExt1. While ORG4 has no similarity with other proteins in the database, ORG1 has weak similarity in different regions of the predicted protein with CDC2 and fibrillin. ORG2 and ORG3 share 80% overall identity in their deduced amino acid sequences and contain a basic helix-loop-helix DNA-binding domain, suggesting that ORG2 and ORG3 may be transcription factors. The expression of the ORG1, ORG2 and ORG3 genes was co-regulated under all conditions examined including upregulation by SA and downregulation by jasmonic acid (JA). Fifteen OBP3-silenced lines were generated to further explore the function of OBP3. Although there were no visible phenotypic changes in any of these lines, the expression of ORG1, ORG2 and ORG3 was reduced. Among the ORG genes, ORG1, ORG2 and ORG3 contained the highest number of potential Dof-binding sites in the promoter region, and their expression was significantly increased within 3 h after induction of OBP3 expression using an inducible promoter system, and closely reflected the expression levels of the exogenous OBP3 protein. The results from the gain-of-function and loss-of-function experiments suggest that the ORG1, ORG2 and ORG3 genes are direct target genes of OBP3.
Identification and characterization of resistance to cowpea aphid (Aphis craccivora Koch) in Medicago truncatula
Publisher: Springer Science and Business Media LLC
Date: 04-07-2012
Abstract: Cowpea aphid (CPA Aphis craccivora ) is the most important insect pest of cowpea and also causes significant yield losses in other legume crops including alfalfa, beans, chickpea, lentils, lupins and peanuts. In many of these crops there is no natural genetic resistance to this sap-sucking insect or resistance genes have been overcome by newly emerged CPA biotypes. In this study, we screened a subset of the Medicago truncatula core collection of the South Australian Research and Development Institute (SARDI) and identified strong resistance to CPA in a M. truncatula accession SA30199, compared to all other M. truncatula accessions tested. The biology of resistance to CPA in SA30199 plants was characterised compared to the highly susceptible accession Borung and showed that resistance occurred at the level of the phloem, required an intact plant and involved a combination of antixenosis and antibiosis. Quantitative trait loci (QTL) analysis using a F 2 population (n = 150) from a cross between SA30199 and Borung revealed that resistance to CPA is controlled in part by a major quantitative trait locus (QTL) on chromosome 2, explaining 39% of the antibiosis resistance. The identification of strong CPA resistance in M. truncatula allows for the identification of key regulators and genes important in this model legume to give effective CPA resistance that may have relevance for other legume crops. The identified locus will also facilitate marker assisted breeding of M. truncatula for increased resistance to CPA and potentially other closely related Medicago species such as alfalfa.
Analysis of type 1 metallothionein cDNAs in Vicia faba
Publisher: Springer Science and Business Media LLC
Date: 1997
Abstract: In animals and fungi, small cysteine-rich proteins called metallothioneins (MTs) play a role in heavy metal tolerance. MT genes have been isolated in plants, but their function remains to be elucidated. We have isolated two distinct Vicia faba MT genes that belong to the type 1 group of plant MT genes in contrast to a MT gene we previously isolated that belongs to type 2. We found similarities and differences between the V. faba MT genes. The RNA expression patterns differed and this was most pronounced in roots, which contained high MT1 but very low MT2 RNA levels. Like MT2, MT1 transcript levels were not significantly affected by treatment with Cd, Cu, Fe and Zn, at least under the experimental conditions. MT RNA levels varied in leaves and stem internodes of different developmental ages, with the highest expression in the older tissue. The levels of MT RNA correlated inversely with endogenous Cd, Cu and Fe levels within different internodes, but not with a number of other metals tested (including Zn). The three bean MTs were expressed in Escherichia coli and found to bind Cd, Cu and Zn but not to Fe. The MTs were tested to determine if they differed in their ability to bind a specific metal but no significant differences in binding were observed.
The Arabidopsis RNA Polymerase II Carboxyl Terminal Domain (CTD) Phosphatase-Like1 (CPL1) is a biotic stress susceptibility gene
Publisher: Springer Science and Business Media LLC
Date: 07-09-2018
DOI: 10.1038/S41598-018-31837-0
Abstract: Crop breeding for improved disease resistance may be achieved through the manipulation of host susceptibility genes. Previously we identified multiple Arabidopsis mutants known as enhanced stress response1 ( esr1 ) that have defects in a KH-domain RNA-binding protein and conferred increased resistance to the root fungal pathogen Fusarium oxysporum . Here, screening the same mutagenized population we discovered two further enhanced stress response mutants that also conferred enhanced resistance to F . oxysporum . These mutants also have enhanced resistance to a leaf fungal pathogen ( Alternaria brassicicola ) and an aphid pest ( Myzus persicae ), but not to the bacterial leaf pathogen Pseudomonas syringae . The causal alleles in these mutants were found to have defects in the ESR1 interacting protein partner RNA Polymerase II Carboxyl Terminal Domain (CTD) Phosphatase-Like1 (CPL1) and subsequently given the allele symbols cpl1-7 and cpl1-8 . These results define a new role for CPL1 as a pathogen and pest susceptibility gene. Global transcriptome analysis and oxidative stress assays showed these cpl1 mutants have increased tolerance to oxidative stress. In particular, components of biotic stress responsive pathways were enriched in cpl1 over wild-type up-regulated gene expression datasets including genes related to defence, heat shock proteins and oxidative stress/redox state processes.
TGA5 acts as a positive and TGA4 acts as a negative regulator of ocs element activity in Arabidopsis roots in response to defence signals
Publisher: Wiley
Date: 19-03-2004
The mitochondrial outer membrane AAA ATP ase AtOM 66 affects cell death and pathogen resistance in A rabidopsis thaliana
Publisher: Wiley
Date: 27-10-2014
DOI: 10.1111/TPJ.12665
Abstract: One of the most stress-responsive genes encoding a mitochondrial protein in Arabidopsis (At3g50930) has been annotated as AtBCS1 (cytochrome bc1 synthase 1), but was previously functionally uncharacterised. Here, we show that the protein encoded by At3g50930 is present as a homo-multimeric protein complex on the outer mitochondrial membrane and lacks the BCS1 domain present in yeast and mammalian BCS1 proteins, with the sequence similarity restricted to the AAA ATPase domain. Thus we propose to re-annotate this protein as AtOM66 (Outer Mitochondrial membrane protein of 66 kDa). While transgenic plants with reduced AtOM66 expression appear to be phenotypically normal, AtOM66 over-expression lines have a distinct phenotype, showing strong leaf curling and reduced starch content. Analysis of mitochondrial protein content demonstrated no detectable changes in mitochondrial respiratory complex protein abundance. Consistent with the stress inducible expression pattern, over-expression lines of AtOM66 are more tolerant to drought stress but undergo stress-induced senescence earlier than wild type. Genome-wide expression analysis revealed a constitutive induction of salicylic acid-related (SA) pathogen defence and cell death genes in over-expression lines. Conversely, expression of SA marker gene PR-1 was reduced in atom66 plants, while jasmonic acid response genes PDF1.2 and VSP2 have increased transcript abundance. In agreement with the expression profile, AtOM66 over-expression plants show increased SA content, accelerated cell death rates and are more tolerant to the biotrophic pathogen Pseudomonas syringae, but more susceptible to the necrotrophic fungus Botrytis cinerea. In conclusion, our results demonstrate a role for AtOM66 in cell death and lifying SA signalling.
INDEL variation in the regulatory region of the major flowering time gene LanFTc1 is associated with vernalization response and flowering time in narrow‐leafed lupin (Lupinus angustifolius
Publisher: Wiley
Date: 23-05-2018
DOI: 10.1111/PCE.13320
Comparative genomics and prediction of conditionally dispensable sequences in legume–infecting Fusarium oxysporum formae speciales facilitates identification of candidate effectors
Publisher: Springer Science and Business Media LLC
Date: 05-03-2016
The auxin, hydrogen peroxide and salicylic acid induced expression of the Arabidopsis GST6 promoter is mediated in part by an ocs element
Publisher: Wiley
Date: 09-1999
DOI: 10.1046/J.1365-313X.1999.00560.X
Abstract: Glutathione S-transferases (GSTs) are multi-functional enzymes that play critical roles in a number of plant stress responses. Ocs elements are enhancer sequences found in some pathogen and GST promoters. We previously isolated an Arabidopsis GST gene, called GST6, which contained an ocs-like element. Here we tested the role this putative ocs element plays in GST6 expression in response to auxin, salicylic acid (SA) and hydrogen peroxide (H2O2) using a transient assay and transgenic Arabidopsis. The requirement for the ocs element for basal and/or induced expression varied between the transient and transgenic studies, and in different plant tissues. The GST6 promoter showed the largest induction in roots following treatment with SA (84-fold) or H2O2 (122-fold), and the effect of mutating the ocs element was most pronounced in root tissue. However, in no case did mutation of the ocs element abolish GST6 expression, suggesting that other promoter element(s) are also important. Using the transient assay, other promoter element(s) critical for GST6 expression were identified that may also help mediate the activity of the ocs element. The finding that the ocs element plays a role in the transcriptional response of a plant GST gene to SA and H2O2 has potential significance for the plant defense response, where SA and H2O2 play critical roles.
Diversifying selection in the wheat stem rust fungus acts predominantly on pathogen-associated gene families and reveals candidate effectors
Publisher: Frontiers Media SA
Date: 09-2014
A Trimethylguanosine Synthase1-like (TGS1) homologue is implicated in vernalisation and flowering time control
Publisher: Springer Science and Business Media LLC
Date: 13-07-2021
DOI: 10.1007/S00122-021-03910-2
Abstract: A plant-specific Trimethylguanosine Synthase1-like homologue was identified as a candidate gene for the efl mutation in narrow-leafed lupin, which alters phenology by reducing vernalisation requirement. The vernalisation pathway is a key component of flowering time control in plants from temperate regions but is not well understood in the legume family. Here we examined vernalisation control in the temperate grain legume species, narrow-leafed lupin ( Lupinus angustifolius L.), and discovered a candidate gene for an ethylene imine mutation ( efl ). The efl mutation changes phenology from late to mid-season flowering and additionally causes transformation from obligate to facultative vernalisation requirement. The efl locus was mapped to pseudochromosome NLL-10 in a recombinant inbred line (RIL) mapping population developed by accelerated single seed descent. Candidate genes were identified in the reference genome, and a erse panel of narrow-leafed lupins was screened to validate mutations specific to accessions with efl . A non-synonymous SNP mutation within an S-adenosyl-L-methionine-dependent methyltransferase protein domain of a Trimethylguanosine Synthase1-like ( TGS1 ) orthologue was identified as the candidate mutation giving rise to efl . This mutation caused substitution of an amino acid within an established motif at a position that is otherwise highly conserved in several plant families and was perfectly correlated with the efl phenotype in F 2 and F 6 genetic population and a panel of erse accessions, including the original efl mutant. Expression of the TGS1 homologue did not differ between wild-type and efl genotypes, supporting altered functional activity of the gene product. This is the first time a TGS1 orthologue has been associated with vernalisation response and flowering time control in any plant species.
DOES THE OCS-ELEMENT OCCUR AS A FUNCTIONAL COMPONENT OF THE PROMOTERS OF PLANT GENES
Publisher: Wiley
Date: 09-1993
DOI: 10.1046/J.1365-313X.1993.04030433.X
Abstract: The structural requirements of the ocs-element, a promoter element in several genes transferred to the host plant nucleus by Agrobacterium tumefaciens and certain DNA viruses, have been further characterized both in vitro and in vivo. Two adjacent and functionally identical protein-binding sites separated by an exact number of nucleotides are required for in vivo activity of the ocs-element. Plant pathogens have presumably recruited cellular transcription factors that interact with these binding sites to drive the high-level expression of their essential genes. Our functional analyses of the ocs-elements from two pathogen promoters define the structure of a sequence motif that might also be expected to occur in plant nuclear genes, and a search of the plant gene database has identified a number of plant gene promoters that contain sequences that resemble the ocs-element. These sequences were analysed for their ability both to bind the maize nuclear protein OCSTF and to activate transcription of an inactive promoter. A functional ocs-element was identified in only one of the plant genes, the soybean heat-shock gene, Gmhsp26-A. The apparent rarity of the ocs-element in plant genes contrasts with its frequent use by pathogens that transform the plant nucleus. Sequences resembling half of an ocs-element, on the other hand, are common in plant promoters and may form part of multi-element control motifs with a variety of regulatory functions. Plant pathogens may, therefore, have evolved to circumvent tight regulatory control of their promoters by the host by duplicating the half ocs-element promoter motifs to take advantage of the ubiquitous ocs-element-binding transcription factors in plants.
Achievements and Challenges in Legume Breeding for Pest and Disease Resistance
Publisher: Informa UK Limited
Date: 24-10-2014
The Arabidopsis glutathione transferase gene family displays complex stress regulation and co‐silencing multiple genes results in altered metabolic sensitivity to oxidative stress
Publisher: Wiley
Date: 26-03-2009
Desensitization of GSTF8 induction by a prior chemical treatment is long lasting and operates in a tissue-dependent manner
Publisher: Oxford University Press (OUP)
Date: 07-07-2006
Abstract: The Arabidopsis (Arabidopsis thaliana) GSTF8 gene is a member of the glutathione S-transferase (GST) family whose expression is induced by defense signals, certain chemical stresses, and some pathogens. Here, we have used transgenic plants and an in vivo imaging system to demonstrate that GSTF8 expression is subject to a distinct desensitization phenomenon because prior chemical treatment significantly reduces reactivation of the GSTF8 promoter by hydrogen peroxide, auxin, and salicylic acid. A GSTF8 null line had similar desensitization properties to wild type, demonstrating that GSTF8 protein levels are not responsible for desensitization. The resulting refractory period is unusually long lasting, with full recovery taking 4 d. Expression of the GSTF8 promoter following a second treatment occurred predominantly in newly formed tissue at the root tip, suggesting that desensitization is lost upon cell ision. Expression of the endogenous GSTF8 gene and another GST gene, GSTF6, is also desensitized following treatment with hydrogen peroxide. The desensitization phenomenon can be activated by a very low concentration of inducer that is not sufficient to activate the GSTF8 promoter. These results demonstrate that activation of the GSTF8 promoter is not essential for eliciting desensitization. A key promoter sequence within the GSTF8 gene, the ocs element, is also affected by desensitization. Treatment with a phosphatase inhibitor prevents desensitization of GSTF8 expression and ocs element activity, suggesting that dephosphorylation of one or more proteins is required for desensitization to occur.
The Medicago truncatula ortholog of Arabidopsis EIN2, sickle, is a negative regulator of symbiotic and pathogenic microbial associations
Publisher: Wiley
Date: 08-2008
Arabidopsis thaliana ethylene-responsive element binding protein (AtEBP), an ethylene-inducible, GCC box DNA-binding protein interacts with an ocs element binding protein
Publisher: Proceedings of the National Academy of Sciences
Date: 27-05-1997
Abstract: Ocs elements are a group of promoter sequences required for the expression of both pathogen genes in infected plants and plant defense genes. Genes for ocs element binding factors (OBFs), belonging to a specific class of basic-region leucine zipper (bZIP) transcription factors, have been isolated in a number of plants. Using protein–protein interaction screening with OBF4 we have isolated AtEBP, an Arabidopsis protein that contains a novel DNA-binding domain, the AP2/EREBP domain. One class of proteins that contain this domain are the tobacco ethylene-responsive element binding proteins (EREBPs). The EREBPs bind the GCC box that confers ethylene responsiveness to a number of pathogenesis related (PR) gene promoters. AtEBP expression is inducible by exogenous ethylene in wild-type plants and AtEBP transcripts are increased in the ctr1-1 mutant, where ethylene-regulated pathways are constitutively active. Electrophoretic mobility-shift assay and DNase I footprint analysis revealed that AtEBP can specifically bind to the GCC box. Interestingly, the highest level of AtEBP expression was detected in callus tissue, where ocs elements are very active. Synergistic effects of the GCC box with ocs elements or the related G-box sequence have been previously observed, for ex le, in the ethylene-induced expression of a PR gene promoter. Our results suggest that cross-coupling between EREBP and bZIP transcription factors occurs and may therefore be important in regulating gene expression during the plant defense response.
Jasmonate Signalling and Defence Responses in the Model Legume Medicago truncatula-A Focus on Responses to Fusarium Wilt Disease
Publisher: MDPI AG
Date: 05-02-2016
Improved prediction of fungal effector proteins from secretomes with EffectorP 2.0
Publisher: Wiley
Date: 11-05-2018
DOI: 10.1111/MPP.12682
A pan-genome and chromosome-length reference genome of narrow-leafed lupin (Lupinus angustifolius) reveals genomic diversity and insights into key industry and biological traits
Publisher: Wiley
Date: 11-08-2022
DOI: 10.1111/TPJ.15885
Abstract: Narrow‐leafed lupin (NLL Lupinus angustifolius ) is a key rotational crop for sustainable farming systems, whose grain is high in protein content. It is a gluten‐free, non‐genetically modified, alternative protein source to soybean ( Glycine max ) and as such has gained interest as a human food ingredient. Here, we present a chromosome‐length reference genome for the species and a pan‐genome assembly comprising 55 NLL lines, including Australian and European cultivars, breeding lines and wild accessions. We present the core and variable genes for the species and report on the absence of essential mycorrhizal associated genes. The genome and pan‐genomes of NLL and its close relative white lupin ( Lupinus albus ) are compared. Furthermore, we provide additional evidence supporting LaRAP2‐7 as the key alkaloid regulatory gene for NLL and demonstrate the NLL genome is underrepresented in classical NLR disease resistance genes compared to other sequenced legume species. The NLL genomic resources generated here coupled with previously generated RNA sequencing datasets provide new opportunities to fast‐track lupin crop improvement.
The Arabidopsis KH-Domain RNA-Binding Protein ESR1 Functions in Components of Jasmonate Signalling, Unlinking Growth Restraint and Resistance to Stress
Publisher: Public Library of Science (PLoS)
Date: 18-05-2015
Involvement of the octadecanoid pathway in bluegreen aphid resistance in Medicago truncatula
Publisher: Scientific Societies
Date: 2007
DOI: 10.1094/MPMI-20-0082
Abstract: Aphids are major insect pests of plants that feed directly from the phloem. We used the model legume Medicago truncatula Gaert. (barrel medic) to elucidate host resistance to aphids and identified a single dominant gene which confers resistance to Acyrthosiphon kondoi Shinji (bluegreen aphid). To understand how this gene conditions resistance to bluegreen aphid, transcription profiling of 23 defense-related genes representing various signaling pathways was undertaken using a pair of near-isogenic lines that are susceptible or resistant to bluegreen aphid. All salicylic acid- and ethylene-responsive genes tested were induced by blue-green aphid in resistant and susceptible plants, although there were some differences in the magnitude and kinetics of the induction. In contrast, 10 of 13 genes associated with the octadecanoid pathway were induced exclusively in the resistant plants following bluegreen aphid infestation. These results are in contrast to plant-pathogen interactions where similar sets of defense genes typically are induced in compatible interactions, but to a lesser degree and later than in incompatible interactions. Treatment of susceptible plants with methyl jasmonate reduced bluegreen aphid infestation but not to the same levels as the resistant line. Together, these results strongly suggest that the octa-decanoid pathway is important for this naturally derived aphid resistance trait.
Quinolizidine alkaloid biosynthesis in lupins and prospects for grain quality improvement
Publisher: Frontiers Media SA
Date: 31-01-2017
Salicylic Acid-Dependent Plant Stress Signaling via Mitochondrial Succinate Dehydrogenase.
Publisher: Oxford University Press (OUP)
Date: 16-02-2017
DOI: 10.1104/PP.16.00060
Expression of enhanced levels of small RNA polymerase III transcripts encoded by the B2 repeats in simian virus 40-transformed mouse cells
Publisher: Springer Science and Business Media LLC
Date: 04-1985
DOI: 10.1038/314553A0
Abstract: Although specific viral genes are known which are sufficient to transform certain types of cells, viral transformation has been shown to be accompanied by a change in the level of expression of cellular genes. Assuming that this latter class of genes is involved in some way in the establishment of the transformed state, we and others have sought to characterize them. To this end, we constructed a complementary DNA library from a simian virus 40 (SV40)-transformed mouse cell line and screened this library for induced genes. Here we focus on the characterization of a specific cDNA clone called 10 lambda 5. We show that the clone 10 lambda 5 contains a B2 repeat, and that the levels of the small heterogeneously sized B2 cytoplasmic RNAs homologous to 10 lambda 5 are enhanced in transformed cells. Our studies show that these RNAs are a specific class of polymerase III transcripts containing a highly conserved 5' end. SV40 transformation results, therefore, in the activation of specific polymerase III transcripts as well as specific polymerase II transcripts.
Functional properties of the anaerobic responsive element of the maize Adh1 gene
Publisher: Springer Science and Business Media LLC
Date: 10-1990
DOI: 10.1007/BF00017834
SATURATION MUTAGENESIS OF THE OCTOPINE SYNTHASE ENHANCER - CORRELATION OF MUTANT PHENOTYPES WITH BINDING OF A NUCLEAR-PROTEIN FACTOR
Publisher: Proceedings of the National Academy of Sciences
Date: 05-1989
Abstract: A 16-base-pair palindrome from the Agrobacterium tumefaciens octopine synthase gene functions as a constitutive enhancer in plant protoplasts. Degenerate oligonucleotide mutagenesis provided single base substitutions at every position in the element and a number of multiple base substitutions. The effects of these changes were determined in transient expression assays with tobacco and maize protoplasts. The majority of single and double base changes had little effect on the activity of the octopine synthase enhancer, but nearly all mutants with more than two base changes had low to essentially no activity. There were five positions where particular single base changes resulted in a 4- to 10-fold loss in enhancer activity. The distribution of these positions within the palindrome was asymmetric. Single base deletions had essentially no activity, demonstrating that the octopine synthase enhancer cannot tolerate internal changes in spacing. We find a strong correlation between mutant phenotype and reduced binding of a protein factor, suggesting that the DNA-protein complex is responsible for the transcriptional enhancement the functionally active form of the DNA-protein complex probably involves more than a single protein molecule. The mutants exhibit similar phenotypes in protoplasts of both tobacco and maize, implying conservation of the DNA-protein interactions of the ocs enhancer sequence in monocotyledonous and dicotyledonous plants.
The Medicago truncatula reference accession A17 has an aberrant chromosomal configuration
Publisher: Wiley
Date: 07-03-2007
DOI: 10.1111/J.1469-8137.2007.02039.X
Abstract: Medicago truncatula (barrel medic) has emerged as a model legume and accession A17 is the reference genotype selected for the sequencing of the genome. In the present study we compare the A17 chromosomal configuration with that of other accessions by examining pollen viability and genetic maps of intraspecific hybrids. Hybrids derived from crosses between M. truncatula accessions, representative of the large genetic variation within the germplasm collection, were evaluated for pollen viability using Alexander's stain. Genetic maps were generated for the following crosses: SA27063 x SA3054 (n = 94), SA27063 x A17 (n = 92), A17 x Borung (n = 99) and A17 x A20 (n = 69). All F(1) in iduals derived from crosses involving A17 showed 50% pollen viability or less. Examination of the recombination frequencies between markers of chromosomes 4 and 8 revealed an apparent genetic linkage between the lower arms of these chromosomes in genetic maps derived from A17. Semisterility and unexpected linkage relationship are both good indicators of a reciprocal translocation. The implications of the A17 distinctive chromosomal rearrangement on studies of genetic mapping, genome sequencing and synteny between species are discussed.
Differential Gene Expression and Subcellular Targeting of Arabidopsis Glutathione S-Transferase F8 Is Achieved through Alternative Transcription Start Sites
Publisher: Elsevier BV
Date: 09-2007
Transcriptome analysis reveals class IX ethylene response factors show specific up-regulation in resistant but not susceptible Medicago truncatula lines following infection with Rhizoctonia solani
Publisher: Springer Science and Business Media LLC
Date: 04-05-2018
Mutant Analysis in Arabidopsis Provides Insight into the Molecular Mode of Action of the Auxinic Herbicide Dicamba
Publisher: Public Library of Science (PLoS)
Date: 08-03-2011
ENHANCED B2 TRANSCRIPTION IN SIMIAN VIRUS-40-TRANSFORMED CELLS IS MEDIATED THROUGH THE FORMATION OF RNA POLYMERASE-III TRANSCRIPTION COMPLEXES ON PREVIOUSLY INACTIVE GENES
Publisher: Proceedings of the National Academy of Sciences
Date: 10-1988
Abstract: RNA polymerase III (pol III) transcribes the highly repeated murine B2 elements. We showed previously that the B2 RNAs are induced 4-fold in normal growing cells and 20-fold in simian virus 40-transformed cells relative to the levels in normal confluent cells. By employing chromatin as a template in a partially purified pol III transcription system, we now demonstrate that the augmented expression results from the formation of pol III transcription complexes on previously inactive B2 genes. Extracts prepared from normal growing cells and transformed cells transcribed cloned pol III templates 5-fold more efficiently than extracts from normal confluent cells. This increase was attributed to 5-fold greater levels of factor IIIC the levels of pol III and factor IIIB were the same in all extracts. We discuss how the levels of IIIC and differing accessibility of this factor to repressed B2 genes mediate the formation of pol III transcription complexes in normal growing and transformed cells.
Transcriptome analysis of the fungal pathogen Fusarium oxysporum f. sp medicaginis during colonisation of resistant and susceptible Medicago truncatula hosts identifies differential pathogenicity profiles and novel candidate effectors
Publisher: Springer Science and Business Media LLC
Date: 03-11-2016
Additive and epistatic interactions between AKR and AIN loci conferring bluegreen aphid resistance and hypersensitivity in Medicago truncatula
Publisher: Oxford University Press (OUP)
Date: 31-08-2019
DOI: 10.1093/JXB/ERZ222
Abstract: We provide the first ex le of epistasis between resistance genes (AKR and AIN) against a phloem-feeding insect (bluegreen aphid).
Genetic and Genomic Analysis of Rhizoctonia solani Interactions with Arabidopsis; Evidence of Resistance Mediated through NADPH Oxidases
Publisher: Public Library of Science (PLoS)
Date: 25-02-2013
Variability in an effector gene promoter of a necrotrophic fungal pathogen dictates epistasis and effector-triggered susceptibility in wheat
Publisher: Cold Spring Harbor Laboratory
Date: 28-07-2021
DOI: 10.1101/2021.07.28.454099
Abstract: The fungus Parastagonospora nodorum uses proteinaceous necrotrophic effectors (NEs) to induce tissue necrosis on wheat leaves during infection, leading to the symptoms of septoria nodorum blotch (SNB). The NEs Tox1 and Tox3 induce necrosis on wheat possessing the dominant susceptibility genes Snn1 and Snn3B1/Snn3D1 , respectively. We previously observed that Tox1 is epistatic to the expression of Tox3 and a quantitative trait locus (QTL) on chromosome 2A that contributes to SNB resistance/susceptibility. The expression of Tox1 is significantly higher in the Australian strain SN15 compared to the American strain SN4. Inspection of the Tox1 promoter region revealed a 401 bp promoter genetic element in SN4 positioned 267 bp upstream of the start codon that is absent in SN15, called PE401. Analysis of the world-wide P. nodorum population revealed that a high proportion of Northern Hemisphere isolates possess PE401 whereas the opposite was observed in the Southern Hemisphere. The presence of PE401 ablates the epistatic effect of Tox1 on the contribution of the SNB 2A QTL but not Tox3 . PE401 was introduced into the Tox1 promoter regulatory region in SN15 to test for direct regulatory roles. Tox1 expression was markedly reduced in the presence of PE401. This suggests a repressor molecule(s) binds PE401 and inhibits Tox1 transcription. Infection assays also demonstrated that P. nodorum which lacks PE401 is more pathogenic on Snn1 wheat varieties than P. nodorum carrying PE401. An infection competition assay between P. nodorum isogenic strains with and without PE401 indicated that the higher Tox1 -expressing strain rescued the reduced virulence of the lower Tox1 -expressing strain on Snn1 wheat. Our study demonstrated that Tox1 exhibits both ‘selfish’ and ‘altruistic’ characteristics. This offers an insight into a ’NE arms race’ that is occurring within the P. nodorum population. The importance of PE401 in breeding for SNB resistance in wheat is discussed. Breeding for durable resistance to fungal diseases in crops is a continual challenge for crop breeders. Fungal pathogens evolve ways to overcome host resistance by masking themselves through effector evolution and evasion of broad-spectrum defense responses. Association studies on mapping populations infected by isolate mixtures are often used by researchers to seek out novel sources of genetic resistance. Disease resistance quantitative trait loci (QTL) are often minor or inconsistent across environments. This is a particular problem with septoria diseases of cereals such as septoria nodorum blotch (SNB) of wheat caused by Parastagonospora nodorum . The fungus uses a suite of necrotrophic effectors (NEs) to cause SNB. We characterised a genetic element, called PE401, in the promoter of the major NE gene Tox1 , which is present in some P. nodorum isolates. PE401 functions as a transcriptional repressor of Tox1 and exerts epistatic control on another major SNB resistance QTL in the host. In the context of crop protection, constant surveillance of the pathogen population for the frequency of PE401 in conjunction with NE ersity will enable agronomists to provide the best advice to growers on which wheat varieties can be tailored to provide optimal SNB resistance to regional pathogen population genotypes.
Identification and profiling of narrow-leafed lupin (Lupinus angustifolius) microRNAs during seed development
Publisher: Springer Science and Business Media LLC
Date: 14-02-2019
The role of jasmonate signalling in quinolizidine alkaloid biosynthesis, wounding and aphid predation response in narrow-leafed lupin
Publisher: CSIRO Publishing
Date: 2019
DOI: 10.1071/FP18278
Abstract: Quinolizidine alkaloids (QAs) are toxic secondary metabolites produced in lupin species that protect the plant against insects. They form in vegetative tissues and accumulate to a different extent in the grains: high levels in ‘bitter’ narrow-leafed lupin (NLL) and low levels in ‘sweet’ NLL. Grain QA levels vary considerably, and sometimes exceed the industry limit for food and feed purposes. We hypothesised that jasmonates regulate QA biosynthesis in response to environmental stresses such as wounding and aphid predation, which may explain non-genetic variability in grain QA levels. Methyl jasmonate (MeJA)-inducible genes were identified and verified in NLL. Exogenous MeJA application-induced expression of QA biosynthetic genes and QA levels for bitter, but not sweet NLL. Although MeJA-inducible genes responded to wounding, the expression of QA biosynthetic genes was not induced for bitter and sweet NLL. We assessed the effect of aphid predation on QA production for two cultivars – one moderately resistant and one susceptible to aphid predation. Although MeJA-inducible genes responded to aphid predation, no change in QA levels was found for either cultivar. These findings offer insights into the regulation of QA biosynthesis in bitter and sweet NLL and concludes that aphids are not a concern for increasing grain QAs in NLL cultivars.
Early induction of the Arabidopsis GSTF8 promoter by specific strains of the fungal pathogen Rhizoctonia solani
Publisher: Scientific Societies
Date: 2004
DOI: 10.1094/MPMI.2004.17.1.70
Abstract: The Arabidopsis glutathione S-transferase GSTF8 promoter directs root-specific responses to stress. In this study, the response of this promoter to plant infection with Rhizoctonia solani was investigated using a luciferase reporter system. Arabidopsis seedlings harboring the GSTF8:luciferase construct were monitored in vivo for bioluminescence following infection with R. solani. Although the reporter gene was induced in infected roots, the response differed markedly between R. solani strains and was not observed with aggressive strains that caused death of the seedlings. The three strains tested in detail progressed through typical stages of infection, but ZG1-1 induced the GSTF8 promoter in most seedlings, ZG3 induced it in approximately 25% of seedlings, and ZG5 caused little response. Induction of specific root segments occurred early in the infection process in root regions with very limited mycelium visible. In root segments with substantial mycelium, GSTF8 promoter activity no longer was observed. Induction by ZG1-1 also was observed in plants harboring a tetramer of the ocs element from the GSTF8 promoter, suggesting that this element helps mediate the response. Crossing GSTF8:luciferase plants with plants harboring an Nah-G construct that degrades salicylic acid did not abolish the response, indicating that the GSTF8 promoter response to R. solani may be mediated by signals other than salicylic acid.
A DNA-BINDING PROTEIN FACTOR RECOGNIZES 2 BINDING DOMAINS WITHIN THE OCTOPINE SYNTHASE ENHANCER ELEMENT
Publisher: JSTOR
Date: 03-1990
DOI: 10.2307/3869136
Reactive oxygen species play a role in the infection of the necrotrophic fungi, Rhizoctonia solani in wheat
Publisher: Public Library of Science (PLoS)
Date: 31-03-2016
Advances and Challenges in Computational Prediction of Effectors from Plant Pathogenic Fungi
Publisher: Public Library of Science (PLoS)
Date: 28-05-2015
Characterization of the genetic factors affecting quinolizidine alkaloid biosynthesis and its response to abiotic stress in narrow-leafed lupin (Lupinus angustifolius L.)
Publisher: Wiley
Date: 10-05-2018
DOI: 10.1111/PCE.13172
Abstract: Quinolizidine alkaloids (QAs) are toxic secondary metabolites that complicate the end use of narrow-leafed lupin (NLL Lupinus angustifolius L.) grain, as levels sometimes exceed the industry limit for its use as a food and feed source. The genotypic and environmental influences on QA production in NLL are poorly understood. Here, the expression of QA biosynthetic genes was analysed in vegetative and reproductive tissues of bitter (high QA) and sweet (low QA) accessions. It was demonstrated that sweet accessions are characterized by lower QA biosynthetic gene expression exclusively in leaf and stem tissues than bitter NLL, consistent with the hypothesis that QAs are predominantly produced in aerial tissues and transported to seeds, rather than synthesized within the seed itself. This analysis informed our identification of additional candidate genes involved in QA biosynthesis. Drought and temperature stress are two major abiotic stresses that often occur during NLL pod set. Hence, we assessed the effect of drought, increased temperature, and their combination, on QA production in three sweet NLL cultivars. A cultivar-specific response to drought and temperature in grain QA levels was observed, including the identification of a cultivar where alkaloid levels did not change with these stress treatments.
Ethylene Signaling Is Important for Isoflavonoid-Mediated Resistance to Rhizoctonia solani in Roots of Medicago truncatula
Publisher: Scientific Societies
Date: 09-2017
DOI: 10.1094/MPMI-03-17-0057-R
Abstract: The root-infecting necrotrophic fungal pathogen Rhizoctoniasolani causes significant disease to all the world’s major food crops. As a model for pathogenesis of legumes, we have examined the interaction of R. solani AG8 with Medicago truncatula. RNAseq analysis of the moderately resistant M. truncatula accession A17 and highly susceptible sickle (skl) mutant (defective in ethylene sensing) identified major early transcriptional reprogramming in A17. Responses specific to A17 included components of ethylene signaling, reactive oxygen species metabolism, and consistent upregulation of the isoflavonoid biosynthesis pathway. Mass spectrometry revealed accumulation of the isoflavonoid-related compounds liquiritigenin, formononetin, medicarpin, and biochanin A in A17. Overexpression of an isoflavone synthase in M. truncatula roots increased isoflavonoid accumulation and resistance to R. solani. Addition of exogenous medicarpin suggested this phytoalexin may be one of several isoflavonoids required to contribute to resistance to R. solani. Together, these results provide evidence for the role of ethylene-mediated accumulation of isoflavonoids during defense against root pathogens in legumes. The involvement of ethylene signaling and isoflavonoids in the regulation of both symbiont-legume and pathogen-legume interactions in the same tissue may suggest tight regulation of these responses are required in the root tissue.
Mitochondrial complex II has a key role in mitochondrial-derived reactive oxygen species influence on plant stress gene regulation and defense
Publisher: Proceedings of the National Academy of Sciences
Date: 13-06-2011
Abstract: Mitochondria are both a source of ATP and a site of reactive oxygen species (ROS) production. However, there is little information on the sites of mitochondrial ROS (mROS) production or the biological role of such mROS in plants. We provide genetic proof that mitochondrial complex II (Complex II) of the electron transport chain contributes to localized mROS that regulates plant stress and defense responses. We identify an Arabidopsis mutant in the Complex II subunit, SDH1-1, through a screen for mutants lacking GSTF8 gene expression in response to salicylic acid (SA). GSTF8 is an early stress-responsive gene whose transcription is induced by biotic and abiotic stresses, and its expression is commonly used as a marker of early stress and defense responses. Transcriptional analysis of this mutant, disrupted in stress responses 1 ( dsr1 ), showed that it had altered SA-mediated gene expression for specific downstream stress and defense genes, and it exhibited increased susceptibility to specific fungal and bacterial pathogens. The dsr1 mutant also showed significantly reduced succinate dehydrogenase activity. Using in vivo fluorescence assays, we demonstrated that root cell ROS production occurred primarily from mitochondria and was lower in the mutant in response to SA. In addition, leaf ROS production was lower in the mutant after avirulent bacterial infection. This mutation, in a conserved region of SDH1-1, is a unique plant mitochondrial mutant that exhibits phenotypes associated with lowered mROS production. It provides critical insights into Complex II function with implications for understanding Complex II's role in mitochondrial diseases across eukaryotes.
Characterization of resistance to multiple aphid species (Hemiptera : Aphididae) in Medicago truncatula
Publisher: Cambridge University Press (CUP)
Date: 02-2007
DOI: 10.1017/S0007485307004786
Abstract: Aphids are phloem-feeding insects that damage many important crops throughout the world yet, compared to plant–pathogen interactions, little is known about the mechanisms by which plants become resistant to aphids. Medicago truncatula (barrel medic) is widely considered as the pre-eminent model legume for genetic and biological research and in Australia is an important pasture species. Six cultivars of M. truncatula with varying levels of resistance to two pests of pasture and forage legumes, the bluegreen aphid Acyrthosiphon kondoi Shinji and the spotted alfalfa aphid Therioaphis trifolii f. maculata . (Buckton) are investigated. Two resistance phenotypes against T. trifolii f. maculata are described, one of which is particularly effective, killing most aphids within 24 h of infestation. Each resistance phenotype provided a similar but somewhat less effective degree of resistance to the closely-related spotted clover aphid Therioaphis trifolii (Monell). In the case of A. kondoi only one resistance phenotype was observed, which did not vary among different genetic backgrounds. None of the observed resistance against A. kondoi or T. trifolii f. maculata significantly affected the performance of green peach aphid Myzus persicae (Sulzer) or cowpea aphid Aphis craccivora Koch. The existence of multiple aphid resistance mechanisms in similar genetic backgrounds of this model plant provides a unique opportunity to characterize the fundamental basis of plant defence to these serious agricultural pests.
Proteomic Analysis of Glutathione S-Transferases of Arabidopsis thaliana Reveals Differential Salicylic Acid-Induced Expression of the Plant-Specific Phi and Tau Classes
Publisher: Springer Science and Business Media LLC
Date: 2004
Transcriptional regulation in plants: The importance of combinatorial control
Publisher: Oxford University Press (OUP)
Date: 12-1998
AtERF14, a Member of the ERF Family of Transcription Factors, Plays a Nonredundant Role in Plant Defense
Publisher: Oxford University Press (OUP)
Date: 17-11-2006
Abstract: We had previously shown that several transcription factors of the ethylene (ET) response factor (ERF) family were induced with different but overlapping kinetics following challenge of Arabidopsis (Arabidopsis thaliana) with Pseudomonas syringae pv tomato DC3000 (avrRpt2). One of these genes, a transcriptional activator, AtERF14, was induced at the same time as ERF-target genes (ChiB, basic chitinase). To unravel the potential function of AtERF14 in regulating the plant defense response, we have analyzed gain- and loss-of-function mutants. We show here that AtERF14 has a prominent role in the plant defense response, since overexpression of AtERF14 had dramatic effects on both plant phenotype and defense gene expression and AtERF14 loss-of-function mutants showed impaired induction of defense genes following exogenous ET treatment and increased susceptibility to Fusarium oxysporum. Moreover, the expression of other ERF genes involved in defense and ET/jasmonic acid responses, such as ERF1 and AtERF2, depends on AtERF14 expression. A number of ERFs have been shown to function in the defense response through overexpression. However, the effect of loss of AtERF14 function on defense gene expression, pathogen resistance, and regulation of the expression of other ERF genes is unique thus far. These results suggest a unique role for AtERF14 in regulating the plant defense response.
OCSBF-1, A MAIZE OCS ENHANCER BINDING-FACTOR - ISOLATION AND EXPRESSION DURING DEVELOPMENT
Publisher: JSTOR
Date: 09-1990
DOI: 10.2307/3869325
Plant-aphid interactions with a focus on legumes
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/FP13090
Abstract: Sap-sucking insects such as aphids cause substantial yield losses in agriculture by draining plant nutrients as well as vectoring viruses. The main method of control in agriculture is through the application of insecticides. However, aphids rapidly evolve mechanisms to detoxify these, so there is a need to develop durable plant resistance to these damaging insect pests. The focus of this review is on aphid interactions with legumes, but work on aphid interactions with other plants, particularly Arabidopsis and tomato is also discussed. This review covers advances on the plant side of the interaction, including the identification of major resistance genes and quantitative trait loci conferring aphid resistance in legumes, basal and resistance gene mediated defence signalling following aphid infestation and the role of specialised metabolites. On the aphid side of the interaction, this review covers what is known about aphid effector proteins and aphid detoxification enzymes. Recent advances in these areas have provided insight into mechanisms underlying resistance to aphids and the strategies used by aphids for successful infestations and have significant impacts for the delivery of durable resistance to aphids in legume crops.
Characterization of narrow-leaf lupin (Lupinus angustifolius L.) recombinant major allergen IgE-binding proteins and the natural β-conglutin counterparts in sweet lupin seed species
Publisher: Elsevier BV
Date: 04-2018
DOI: 10.1016/J.FOODCHEM.2017.10.015
Abstract: β-conglutin has been identified as a major allergen for Lupinus angustifolius seeds. The aim of this study was to evaluate the binding of IgE to five recombinant β-conglutin isoforms (rβ) that we overexpressed and purified and to their natural counterparts in different lupin species and cultivars. Western blotting suggested β-conglutins were the main proteins responsible for the IgE reactivity of the lupin species and cultivars. Newly identified polypeptides from "sweet lupin" may constitute a potential new source of primary or cross-reactive sensitization to lupin, particularly to L. albus and L. angustifolius seed proteins. Several of them exhibited qualitative and quantitative differences in IgE-binding among these species and cultivars, mainly in sera from atopic patients that react to lupin rather than peanut. IgE-binding was more consistent to recombinant β2 than to any of the other isoforms, making this protein a potential candidate for diagnosis and immunotherapy.
Characterization and mapping of LanrBo: a locus conferring anthracnose resistance in narrow-leafed lupin (Lupinus angustifolius L.)
Publisher: Springer Science and Business Media LLC
Date: 14-07-2015
DOI: 10.1007/S00122-015-2572-3
Abstract: A novel and highly effective source of anthracnose resistance in narrow-leafed lupin was identified. Resistance was shown to be governed by a single dominant locus. Molecular markers have been developed, which can be used for selecting resistant genotypes in lupin breeding. A screening for anthracnose resistance of a set of plant genetic resources of narrow-leafed lupin (Lupinus angustifolius L.) identified the breeding line Bo7212 as being highly resistant to anthracnose (Colletotrichum lupini). Segregation analysis indicated that the resistance of Bo7212 is inherited by a single dominant locus. The corresponding resistance gene was given the designation LanrBo. Previously published molecular anchor markers allowed us to locate LanrBo on linkage group NLL-11 of narrow-leafed lupin. Using information from RNAseq data obtained with inoculated resistant vs. susceptible lupin entries as well as EST-sequence information from the model genome Lotus japonicus, additional SNP and EST markers linked to LanrBo were derived. A bracket of two LanrBo-flanking markers allows for precise marker-assisted selection of the novel resistance gene in narrow-leafed lupin breeding programs.
The novel avirulence effector AlAvr1 from Ascochyta lentis mediates host cultivar specificity of ascochyta blight in lentil
Publisher: Wiley
Date: 04-03-2022
DOI: 10.1111/MPP.13203
Abstract: Ascochyta lentis is a fungal pathogen that causes ascochyta blight in the important grain legume species lentil, but little is known about the molecular mechanism of disease or host specificity. We employed a map‐based cloning approach using a biparental A . lentis population to clone the gene AlAvr1‐1 that encodes avirulence towards the lentil cultivar PBA Hurricane XT. The mapping population was produced by mating A . lentis isolate P94‐24, which is pathogenic on the cultivar Nipper and avirulent towards Hurricane, and the isolate Al Kewell, which is pathogenic towards Hurricane but not Nipper. Using agroinfiltration, we found that AlAvr1‐1 from the isolate P94‐24 causes necrosis in Hurricane but not in Nipper. The homologous corresponding gene in Al Kewell, AlAvr1‐2 , encodes a protein with amino acid variation at 23 sites and four of these sites have been positively selected in the P94‐24 branch of the phylogeny. Loss of AlAvr1‐1 in a gene knockout experiment produced a P94‐24 mutant strain that is virulent on Hurricane. Deletion of AlAvr1‐2 in Al Kewell led to reduced pathogenicity on Hurricane, suggesting that the gene may contribute to disease in Hurricane. Deletion of AlAvr1‐2 did not affect virulence for Nipper and AlAvr1‐2 is therefore not an avirulence gene for Nipper. We conclude that the hemibiotrophic pathogen A . lentis has an avirulence effector, AlAvr1‐1, that triggers a hypersensitive resistance response in Hurricane. This is the first avirulence gene to be characterized in a legume pathogen from the Pleosporales and may help progress research on other damaging Ascochyta pathogens.
A novel phloem-specific gene is expressed preferentially in aerial portions of Vicia faba
Publisher: Springer Science and Business Media LLC
Date: 02-1996
DOI: 10.1007/BF00019004
The promoter of a H2O2-inducible, Arabidopsis glutathione S-transferase gene contains closely linked OBF- and OBP1-binding sites
Publisher: Wiley
Date: 12-1996
DOI: 10.1046/J.1365-313X.1996.10060955.X
Abstract: Glutathione S-transferases (GSTs) are a family of multifunctional enzymes that play critical roles in the detoxification of xenobiotics and the protection of tissues against oxidative damage. GSTs are important enzymes in plant responses to a number of environmental stresses including herbicides and pathogen attack. Ocs elements are a group of related, 20 bp promoter elements which have been exploited by some plant pathogens to express genes in plants. Ocs elements have also been found to regulate the expression of a plant GST promoter. An Arabidopsis GST gene, called GST6 has been isolated. GST6 expression is under tissue-specific control and is induced following treatment with auxin, salicylic acid and H2O2. The GST6 promoter contains a binding site for two Arabidopsis ocs element binding factors (OBF), that has some sequence homology to ocs element sequences. Interestingly, OBP1 (OBF binding protein), a DNA-binding protein that was isolated by screening an Arabidopsis cDNA library with a labeled OBF protein as a probe, binds next to the OBF-binding site on the GST6 promoter. OBP1 was able to significantly stimulate the binding of OBF proteins to the GST6 promoter, raising the possibility that interactions between the OBP1 and OBF proteins may be important for GST6 expression.
Identification of Arabidopsis Ethylene-Responsive Element Binding Factors with Distinct Induction Kinetics after Pathogen Infection,
Publisher: Oxford University Press (OUP)
Date: 04-2002
DOI: 10.1104/PP.010862
Abstract: Ethylene-responsive element binding factors (ERF) proteins are plant-specific transcription factors, many of which have been linked to stress responses. We have identified four Arabidopsis ERF genes whose expression was specifically induced by avirulent and virulent strains of the bacterial pathogen Pseudomonas syringae pv tomato, with overlapping but distinct induction kinetics. However, a delay in ERFmRNA accumulation after infection with the virulent strain was observed when compared with the avirulent strain. The induction ofERF gene expression in most cases preceded the mRNA accumulation of a basic chitinase gene, a potential downstream target for one or more of these ERFs. The expression of the ERFgenes was examined among different Arabidopsis tissues, in response to the signaling molecules ethylene, methyl jasmonate, and salicylic acid (SA), and in Arabidopsis mutants with decreased or enhanced susceptibility to pathogens, and significant differences were observed. For ex le, in seedlings, some of the ERF genes were not induced by SA in the wild-type but were SA responsive in thepad4-1 mutant, suggesting that PAD4-1, which acts upstream of SA accumulation, is also involved in repressing the SA-induced expression of specific ERF genes. The four ERF proteins were shown to contain transcriptional activation domains. These results suggest that transcriptional activation cascades involving ERF proteins may be important for plant defense to pathogen attack and that some ERF family members could be involved in the cross-talk between SA- and jasmonic acid-signaling pathways.
Development of genomic resources for the narrow-leafed lupin (Lupinus angustifolius): Construction of a bacterial artificial chromosome (BAC) library and BAC-end sequencing
Publisher: Springer Science and Business Media LLC
Date: 21-10-2011
Abstract: Lupinus angustifolius L, also known as narrow-leafed lupin (NLL), is becoming an important grain legume crop that is valuable for sustainable farming and is becoming recognised as a potential human health food. Recent interest is being directed at NLL to improve grain production, disease and pest management and health benefits of the grain. However, studies have been hindered by a lack of extensive genomic resources for the species. A NLL BAC library was constructed consisting of 111,360 clones with an average insert size of 99.7 Kbp from cv Tanjil. The library has approximately 12 × genome coverage. Both ends of 9600 randomly selected BAC clones were sequenced to generate 13985 BAC end-sequences (BESs), covering approximately 1% of the NLL genome. These BESs permitted a preliminary characterisation of the NLL genome such as organisation and composition, with the BESs having approximately 39% G:C content, 16.6% repetitive DNA and 5.4% putative gene-encoding regions. From the BESs 9966 simple sequence repeat (SSR) motifs were identified and some of these are shown to be potential markers. The NLL BAC library and BAC-end sequences are powerful resources for genetic and genomic research on lupin. These resources will provide a robust platform for future high-resolution mapping, map-based cloning, comparative genomics and assembly of whole-genome sequencing data for the species.
The Arabidopsis altered in stress response2 is impaired in resistance to root and leaf necrotrophic fungal pathogens
Publisher: MDPI AG
Date: 11-03-2019
Abstract: The Arabidopsis thaliana Glutathione S-transferase Phi8 (GSTF8) gene is recognised as a marker for early defence and stress responses. To identify regulators of these responses, a forward genetic screen for Arabidopsis mutants with up-regulated GSTF8 promoter activity was conducted by screening a mutagenized population containing a GSTF8 promoter fragment fused to the luciferase reporter gene (GSTF8:LUC). We previously identified several enhanced stress response (esr) mutants from this screen that conferred constitutive GSTF8:LUC activity and increased resistance to several pathogens and/or insects pests. Here we identified a further mutant constitutively expressing GSTF8:LUC and termed altered in stress response2 (asr2). Unlike the esr mutants, asr2 was more susceptible to disease symptom development induced by two necrotrophic fungal pathogens the root pathogen Fusarium oxysporum, and the leaf pathogen Alternaria brassicicola. The asr2 allele was mapped to a 2.1 Mbp region of chromosome 2 and narrowed to four candidate loci.
Mass-spectrometry data for Rhizoctonia solani proteins produced during infection of wheat and vegetative growth
Publisher: Elsevier BV
Date: 09-2016
Comparative secretome analysis of Rhizoctonia solani isolates with different host ranges reveals unique secretomes and cell death inducing effectors
Publisher: Springer Science and Business Media LLC
Date: 05-09-2017
DOI: 10.1038/S41598-017-10405-Y
Abstract: Rhizoctonia solani is a fungal pathogen causing substantial damage to many of the worlds’ largest food crops including wheat, rice, maize and soybean. Despite impacting global food security, little is known about the pathogenicity mechanisms employed by R. solani . To enable prediction of effectors possessing either broad efficacy or host specificity, a combined secretome was constructed from a monocot specific isolate, a dicot specific isolate and broad host range isolate infecting both monocot and dicot hosts. Secretome analysis suggested R. solani employs largely different virulence mechanisms to well-studied pathogens, despite in many instances infecting the same host plants. Furthermore, the secretome of the broad host range AG8 isolate may be shaped by maintaining functions for saprophytic life stages while minimising opportunities for host plant recognition. Analysis of possible co-evolution with host plants and in-planta up-regulation in particular, aided identification of effectors including xylanase and inhibitor I9 domain containing proteins able to induce cell death in-planta . The inhibitor I9 domain was more abundant in the secretomes of a wide range of necrotising fungi relative to biotrophs. These findings provide novel targets for further dissection of the virulence mechanisms and potential avenues to control this under-characterised but important pathogen.
Identification and characterisation of seed storage protein transcripts from Lupinus angustifolius
Publisher: Springer Science and Business Media LLC
Date: 04-04-2011
Abstract: In legumes, seed storage proteins are important for the developing seedling and are an important source of protein for humans and animals. Lupinus angustifolius (L.), also known as narrow-leaf lupin (NLL) is a grain legume crop that is gaining recognition as a potential human health food as the grain is high in protein and dietary fibre, gluten-free and low in fat and starch. Genes encoding the seed storage proteins of NLL were characterised by sequencing cDNA clones derived from developing seeds. Four families of seed storage proteins were identified and comprised three unique α, seven β, two γ and four δ conglutins. This study added eleven new expressed storage protein genes for the species. A comparison of the deduced amino acid sequences of NLL conglutins with those available for the storage proteins of Lupinus albus (L.), Pisum sativum (L.), Medicago truncatula (L.), Arachis hypogaea (L.) and Glycine max (L.) permitted the analysis of a phylogenetic relationships between proteins and demonstrated, in general, that the strongest conservation occurred within species. In the case of 7S globulin (β conglutins) and 2S sulphur-rich albumin (δ conglutins), the analysis suggests that gene duplication occurred after legume speciation. This contrasted with 11S globulin (α conglutin) and basic 7S (γ conglutin) sequences where some of these sequences appear to have erged prior to speciation. The most abundant NLL conglutin family was β (56%), followed by α (24%), δ (15%) and γ (6%) and the transcript levels of these genes increased 10 3 to 10 6 fold during seed development. We used the 16 NLL conglutin sequences identified here to determine that for in iduals specifically allergic to lupin, all seven members of the β conglutin family were potential allergens. This study has characterised 16 seed storage protein genes in NLL including 11 newly-identified members. It has helped lay the foundation for efforts to use molecular breeding approaches to improve lupins, for ex le by reducing allergens or increasing the expression of specific seed storage protein(s) with desirable nutritional properties.
Chromatin-immunoprecipitation reveals the PnPf2 transcriptional network controlling effector-mediated virulence in a fungal pathogen of wheat
Publisher: Cold Spring Harbor Laboratory
Date: 17-06-2022
DOI: 10.1101/2022.06.16.496517
Abstract: The regulation of virulence in plant-pathogenic fungi has emerged as a key area of importance underlying host infections. Recent work has highlighted the role of transcription factors (TFs) that mediate the expression of virulence-associated genes. A prominent ex le is Pf2, a member of the Zn 2 Cys 6 family of fungal TFs, where orthologues regulate the expression of genes linked to parasitism in several plant-pathogen lineages. These include PnPf2 which controls effector-gene expression in Parastagonospora nodorum , thereby determining the outcome of effector-triggered susceptibility on its host, wheat. PnPf2 is a promising target for disease suppression but the genomic targets, or whether other are regulators involved, remain unknown. This study used chromatin immunoprecipitation (ChIP-seq) and a mutagenesis analysis to investigate these components. Two distinct binding motifs connected to positive gene-regulation were characterised and genes directly targeted by PnPf2 were identified. These included genes encoding major effectors and other components associated with the P. nodorum pathogenic lifestyle, such as carbohydrate-active enzymes and nutrient assimilators. This supports a direct involvement of PnPf2 in coordinating virulence on wheat. Other TFs were also prominent PnPf2 targets, suggesting it also operates within a transcriptional network. Several TFs were therefore functionally investigated in connection to fungal virulence. Distinct metabolic and developmental roles were evident for the newly characterised PnPro1, PnAda1, PnEbr1 and the carbon-catabolite repressor PnCreA. Overall, the results uphold PnPf2 as the central transcriptional regulator orchestrating genes that contribute to virulence on wheat and provide mechanistic insight into how this occurs. Fungal pathogens cause large crop losses worldwide and consequently much attention has focused on improving host genetic resistance to diseases. These pathogens use effectors, which require coordinated expression at specific stages of the pathogenic lifecycle, to manipulate the host plant metabolism in favour of infection. However, our understanding of the underlying regulatory network in coordination with other genes involved in fungal pathogenicity is lacking. The Pf2 TF orthologues are key players underpinning virulence and effector gene expression in several fungal phytopathogens, including P. nodorum . This study provided significant insight into the DNA-binding regulatory mechanisms of P. nodorum PnPf2, as well as further evidence that it is central to the coordination of virulence. In the context of crop protection, the Pf2 taxonomic orthologues present opportune targets in major fungal pathogens that can be perturbed to reduce the impact of effector triggered-susceptibility and improve disease resistance.
LOCALIZER: subcellular localization prediction of both plant and effector proteins in the plant cell
Publisher: Springer Science and Business Media LLC
Date: 16-03-2017
DOI: 10.1038/SREP44598
Abstract: Pathogens secrete effector proteins and many operate inside plant cells to enable infection. Some effectors have been found to enter subcellular compartments by mimicking host targeting sequences. Although many computational methods exist to predict plant protein subcellular localization, they perform poorly for effectors. We introduce LOCALIZER for predicting plant and effector protein localization to chloroplasts, mitochondria, and nuclei. LOCALIZER shows greater prediction accuracy for chloroplast and mitochondrial targeting compared to other methods for 652 plant proteins. For 107 eukaryotic effectors, LOCALIZER outperforms other methods and predicts a previously unrecognized chloroplast transit peptide for the ToxA effector, which we show translocates into tobacco chloroplasts. Secretome-wide predictions and confocal microscopy reveal that rust fungi might have evolved multiple effectors that target chloroplasts or nuclei. LOCALIZER is the first method for predicting effector localisation in plants and is a valuable tool for prioritizing effector candidates for functional investigations. LOCALIZER is available at localizer.csiro.au/ .
Exploring the genetic and adaptive diversity of a pan-Mediterranean crop wild relative: narrow-leafed lupin
Publisher: Springer Science and Business Media LLC
Date: 20-01-2018
APOPLASTP: prediction of effectors and plant proteins in the apoplast using machine learning
Publisher: Wiley
Date: 15-12-2018
DOI: 10.1111/NPH.14946
Abstract: The plant apoplast is integral to intercellular signalling, transport and plant-pathogen interactions. Plant pathogens deliver effectors both into the apoplast and inside host cells, but no computational method currently exists to discriminate between these localizations. We present ApoplastP, the first method for predicting whether an effector or plant protein localizes to the apoplast. ApoplastP uncovers features of apoplastic localization common to both effectors and plant proteins, namely depletion in glutamic acid, acidic amino acids and charged amino acids and enrichment in small amino acids. ApoplastP predicts apoplastic localization in effectors with a sensitivity of 75% and a false positive rate of 5%, improving the accuracy of cysteine-rich classifiers by > 13%. ApoplastP does not depend on the presence of a signal peptide and correctly predicts the localization of unconventionally secreted proteins. The secretomes of fungal saprophytes as well as necrotrophic, hemibiotrophic and extracellular fungal pathogens are enriched for predicted apoplastic proteins. Rust pathogens have low proportions of predicted apoplastic proteins, but these are highly enriched for predicted effectors. ApoplastP pioneers apoplastic localization prediction using machine learning. It will facilitate functional studies and will be valuable for predicting if an effector localizes to the apoplast or if it enters plant cells.
The B-3 Ethylene Response Factor MtERF1-1 Mediates Resistance to a Subset of Root Pathogens inMedicago truncatulawithout Adversely Affecting Symbiosis with Rhizobia
Publisher: Oxford University Press (OUP)
Date: 16-08-2010
Abstract: The fungal necrotrophic pathogen Rhizoctonia solani is a significant constraint to a range of crops as erse as cereals, canola, and legumes. Despite wide-ranging germplasm screens in many of these crops, no strong genetic resistance has been identified, suggesting that alternative strategies to improve resistance are required. In this study, we characterize moderate resistance to R. solani anastomosis group 8 identified in Medicago truncatula. The activity of the ethylene- and jasmonate-responsive GCC box promoter element was associated with moderate resistance, as was the induction of the B-3 subgroup of ethylene response transcription factors (ERFs). Genes of the B-1 subgroup showed no significant response to R. solani infection. Overexpression of a B-3 ERF, MtERF1-1, in Medicago roots increased resistance to R. solani as well as an oomycete root pathogen, Phytophthora medicaginis, but not root knot nematode. These results indicate that targeting specific regulators of ethylene defense may enhance resistance to an important subset of root pathogens. We also demonstrate that overexpression of MtERF1-1 enhances disease resistance without apparent impact on nodulation in the A17 background, while overexpression in sickle reduced the hypernodulation phenotype. This suggests that under normal regulation of nodulation, enhanced resistance to root diseases can be uncoupled from symbiotic plant-microbe interactions in the same tissue and that ethylene/ERF regulation of nodule number is distinct from the defenses regulated by B-3 ERFs. Furthermore, unlike the stunted phenotype previously described for Arabidopsis (Arabidopsis thaliana) ubiquitously overexpressing B-3 ERFs, overexpression of MtERF1-1 in M. truncatula roots did not show adverse effects on plant development.
Plants versus pathogens: an evolutionary arms race
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/FP09304
Abstract: The analysis of plant–pathogen interactions is a rapidly moving research field and one that is very important for productive agricultural systems. The focus of this review is on the evolution of plant defence responses and the coevolution of their pathogens, primarily from a molecular-genetic perspective. It explores the evolution of the major types of plant defence responses including pathogen associated molecular patterns and effector triggered immunity as well as the forces driving pathogen evolution, such as the mechanisms by which pathogen lineages and species evolve. Advances in our understanding of plant defence signalling, stomatal regulation, R gene–effector interactions and host specific toxins are used to highlight recent insights into the coevolutionary arms race between pathogens and plants. Finally, the review considers the intriguing question of how plants have evolved the ability to distinguish friends such as rhizobia and mycorrhiza from their many foes.
Variability in an effector gene promoter of a necrotrophic fungal pathogen dictates epistasis and effector-triggered susceptibility in wheat
Publisher: Public Library of Science (PLoS)
Date: 06-01-2022
DOI: 10.1371/JOURNAL.PPAT.1010149
Abstract: The fungus Parastagonospora nodorum uses proteinaceous necrotrophic effectors (NEs) to induce tissue necrosis on wheat leaves during infection, leading to the symptoms of septoria nodorum blotch (SNB). The NEs Tox1 and Tox3 induce necrosis on wheat possessing the dominant susceptibility genes Snn1 and Snn3B1/Snn3D1 , respectively. We previously observed that Tox1 is epistatic to the expression of Tox3 and a quantitative trait locus (QTL) on chromosome 2A that contributes to SNB resistance/susceptibility. The expression of Tox1 is significantly higher in the Australian strain SN15 compared to the American strain SN4. Inspection of the Tox1 promoter region revealed a 401 bp promoter genetic element in SN4 positioned 267 bp upstream of the start codon that is absent in SN15, called PE401. Analysis of the world-wide P . nodorum population revealed that a high proportion of Northern Hemisphere isolates possess PE401 whereas the opposite was observed in representative P . nodorum isolates from Australia and South Africa. The presence of PE401 removed the epistatic effect of Tox1 on the contribution of the SNB 2A QTL but not Tox3 . PE401 was introduced into the Tox1 promoter regulatory region in SN15 to test for direct regulatory roles. Tox1 expression was markedly reduced in the presence of PE401. This suggests a repressor molecule(s) binds PE401 and inhibits Tox1 transcription. Infection assays also demonstrated that P . nodorum which lacks PE401 is more pathogenic on Snn1 wheat varieties than P . nodorum carrying PE401. An infection competition assay between P . nodorum isogenic strains with and without PE401 indicated that the higher Tox1 -expressing strain rescued the reduced virulence of the lower Tox1 -expressing strain on Snn1 wheat. Our study demonstrated that Tox1 exhibits both ‘selfish’ and ‘altruistic’ characteristics. This offers an insight into a complex NE-NE interaction that is occurring within the P . nodorum population. The importance of PE401 in breeding for SNB resistance in wheat is discussed.
Interactions of Arabidopsis and M. truncatula with the same pathogens differ in dependence on ethylene and ethylene response factors
Publisher: Informa UK Limited
Date: 04-2011
Plant defence responses: what have we learnt from Arabidopsis?
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/FP04135
Abstract: To overcome the attack of invading pathogens, a plant’s defence system relies on preformed and induced responses. The induced responses are activated following detection of a pathogen, with the subsequent transmission of signals and orchestrated cellular events aimed at eliminating the pathogen and preventing its spread. Numerous studies are proving that the activated signalling pathways are not simply linear, but rather, form complex networks where considerable cross talk takes place. This review covers the recent application of powerful genetic and genomic approaches to identify key defence signalling pathways in the model plant Arabidopsis thaliana (L.) Heynh. The identification of key regulatory components of these pathways may offer new approaches to increase the defence capabilities of crop plants.
Plant defence responses: conservation between models and crops
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/FP04136
Abstract: Diseases of plants are a major problem for agriculture world wide. Understanding the mechanisms employed by plants to defend themselves against pathogens may lead to novel strategies to enhance disease resistance in crop plants. Much of the research in this area has been conducted with Arabidopsis as a model system, and this review focuses on how relevant the knowledge generated from this model system will be for increasing resistance in crop plants. In addition, the progress made using other model plant species is discussed. While there appears to be substantial similarity between the defence responses of Arabidopsis and other plants, there are also areas where significant differences are evident. For this reason it is also necessary to increase our understanding of the specific aspects of the defence response that cannot be studied using Arabidopsis as a model.
Transcription factor lineages in plant-pathogenic fungi, connecting diversity with fungal virulence
Publisher: Cold Spring Harbor Laboratory
Date: 16-12-2021
DOI: 10.1101/2021.12.16.472873
Abstract: Plant-pathogenic fungi span erse taxonomic lineages. Their host-infection strategies are often specialised and require the coordinated regulation of molecular virulence factors. Transcription factors (TFs) are fundamental regulators of gene expression, controlling development and virulence in plant pathogenic fungi. Recent research has established regulatory roles for several taxonomically conserved fungal TFs, but the evolution of specific virulence regulators is not well understood. This study sought to explore the representation of TFs across a taxonomically- erse range of fungi, with a focus on plant pathogens. A significant trend was observed among the obligate, host-associated pathogens, which possess a reduced overall TF repertoire, alluding to a lack of pressure for maintaining ersity. A novel orthology-based analysis is then presented that refined TF classifications, traditionally based on the nature of the DNA-binding domains. Using this analysis, cases of TF over/underrepresentation across fungal pathogen lineages are systematically highlighted. Specific ex les are then explored and discussed that included the TF orthologues of Ste12, Pf2 and EBR1, plus phytotoxic secondary-metabolite cluster regulators, which all presented novel and distinct evolutionary insights. Ultimately, as the ex les presented demonstrate, this resource can be interrogated to guide functional studies that seek to characterise virulence-specific regulators and shed light on the factors underpinning plant pathogenicity.
Transcriptome sequencing of different narrow-leafed lupin tissue types provides a comprehensive uni-gene assembly and extensive gene-based molecular markers
Publisher: Wiley
Date: 24-07-0026
DOI: 10.1111/PBI.12229
OCS ELEMENT PROMOTER SEQUENCES ARE ACTIVATED BY AUXIN AND SALICYLIC-ACID IN ARABIDOPSIS
Publisher: Proceedings of the National Academy of Sciences
Date: 29-03-1994
Abstract: ocs elements are a group of promoter elements that have been exploited by two distinct groups of plant pathogens, Agrobacterium and certain viruses, to express genes in plants. We examined the activity of single and multiple ocs elements linked to a minimal plant promoter and the uidA reporter gene in transgenic Arabidopsis. beta-Glucuronidase activity was detected only in root tips and in callus tissue after auxin treatment. A more sensitive assay revealed that auxin treatment also increased ocs element activity in aerial parts of the plant, although the absolute levels of ocs element activity were greater in roots. The response of ocs elements to exogenous auxin began within 1 h. Salicylic acid, a disease-resistance signal in plants, also increased ocs element activity in both roots and aerial parts of the plant. The question of whether the induction in ocs element activity is mediated through auxin and/or salicylic acid signal transduction pathways or is part of a more general stress response is discussed.
Resistance to insect pests: What do legumes have to offer?
Publisher: Springer Science and Business Media LLC
Date: 2006
Analysis of conglutin seed storage proteins across lupin species using transcriptomic, protein and comparative genomic approaches
Publisher: Springer Science and Business Media LLC
Date: 19-04-2015
Genomic resources for lupins are coming of age
Publisher: Wiley
Date: 16-03-2021
DOI: 10.1002/LEG3.77
Abstract: Lupins are underutilised pulse crops subject to increasing interest for human consumption of the high‐protein grain. They are also valued as a source of animal nutrition and make an excellent break crop in agricultural production systems. Like other orphan legumes, the genomic revolution has made it cost‐effective to also apply modern genetic and genomic approaches in lupins. These have predominantly been conducted in the two major domesticated lupin species, namely, narrow‐leafed lupin (NLL Lupinus angustifolius ) and white lupin ( Lupinus albus ), with transcriptome studies also emerging in other domesticated and undomesticated species. This review provides an overview of the current lupin genomic resources developed including two reference genomes for NLL and white lupin, several transcriptome resources and the development of pan‐genomes for NLL and white lupin, and describes how these offer great potential to increase grain yield and quality for these recently domesticated pulse crops. Furthermore, we highlight the importance of lupins to further our understanding of many aspects of fundamental legume biology. Combined, this will aid breeders and growers to improve lupin crops to help meet the increasing demand for plant protein in more sustainable cropping systems.
Characterization of salicylic acid-responsive, Arabidopsis Dof domain proteins: overexpression of OBP3 leads to growth defects
Publisher: Wiley
Date: 02-2000
DOI: 10.1046/J.1365-313X.2000.00678.X
Abstract: Dof proteins are unique to plants and contain a single zinc finger DNA-binding domain called the Dof domain. OBP1, an Arabidopsis Dof protein, was previously isolated through an interaction with OBF4, an ocs element-binding protein. Two additional Dof proteins, called OBP2 and OBP3, were isolated through homologous screening. All three OBP proteins contain transcriptional activation domains in their C-terminal region. While no significant differences were found between the OBP proteins in terms of their DNA and protein-binding properties, tissue-specific RNA expression patterns were found. The RNA expression levels of all three OBP proteins increased following treatment with auxin, salicylic acid (SA) or cycloheximide, although the level of induction varied among the different proteins and in the tissues tested. These results suggest that even though they have similar DNA binding and protein-protein interaction properties, the different OBP proteins are likely to have distinct functions in specific parts of the plant. There is a good correlation between the expression of the OBP proteins and the ocs element, a stress-response element which is also induced by auxin, SA and cycloheximide. To begin to analyze the function of the OBP proteins, transgenic lines overexpressing OBP3 were generated. These plants showed a severe growth defect with altered root development and yellowish leaves. The severity of the growth defects correlated with OBP3 expression levels and in some cases led to death, suggesting that some Dof proteins play important roles in plant growth and development.
A single gene, AIN, in Medicago truncatula mediates a hypersensitive response to both bluegreen aphid and pea aphid, but confers resistance only to bluegreen aphid
Publisher: Oxford University Press (OUP)
Date: 18-08-2009
DOI: 10.1093/JXB/ERP244
Biotechnology approaches to overcome biotic and abiotic stress constraints in legumes
Publisher: Springer Science and Business Media LLC
Date: 2006
A comprehensive draft genome sequence for lupin (Lupinus angustifolius), an emerging health food: insights into plant–microbe interactions and legume evolution
Publisher: Wiley
Date: 23-09-2017
DOI: 10.1111/PBI.12615
Breeding Annual Grain Legumes for Sustainable Agriculture: New Methods to Approach Complex Traits and Target New Cultivar Ideotypes
Publisher: Informa UK Limited
Date: 24-10-2014
Genetic mapping of a major resistance gene to pea aphid (Acyrthosipon pisum) in the model legume Medicago truncatula
Publisher: MDPI AG
Date: 29-07-2016
DOI: 10.3390/IJMS17081224
Genome Sequencing and Comparative Genomics of the Broad Host-Range Pathogen Rhizoctonia solani AG8
Publisher: Public Library of Science (PLoS)
Date: 08-05-2014
Narrow-Leafed Lupin (Lupinus angustifolius) beta 1-and beta 6-Conglutin Proteins Exhibit Antifungal Activity, Protecting Plants against Necrotrophic Pathogen Induced Damage from Sclerotinia sclerotiorum and Phytophthora nicotianae
Publisher: Frontiers Media SA
Date: 09-12-2016
Isolation of a Vicia faba metallothionein-like gene: expression in foliar trichomes
Publisher: Springer Science and Business Media LLC
Date: 10-1994
DOI: 10.1007/BF00039552
Abstract: External appearance is the main aesthetic outcome in patients who undergo surgical procedures. Scars located in exposed areas, such as the neck and face, are important for patients. There are at least eight instruments that are used to evaluate postoperative scars, but few fulfil standard methodological conditions. The Patient Scar Assessment Questionnaire (PSAQ) was designed and validated using psychometric methodology. However, this scale has not been translated or validated in the Spanish language. The aim of this study was to undergo a cross-cultural adaptation and psychometric validation of the PSAQ scale to the Spanish language in patients who underwent head and neck surgery. We followed The Professional Society for Health Economics and Outcomes Research (ISPOR) guidelines for the translation and validation of health-related scales. Forward and back translations were made by independent translators. We included adult patients who underwent thyroidectomy, parathyroidectomy, parotidectomy, and neck dissection. For the psychometric validation, we used a principal axis exploratory factor analysis with oblimin rotation. A reliability test involving Cronbachs alpha and the item-total correlation was performed and for the convergent/concurrent validity, we selected the Spanish version of the Vancouver Scar Scale. A total of 180 patients were recruited. Factor analysis showed a five-factor solution. Cronbachs alpha for the subscales was >0.7. The comparison between the PSAQ appearance subscale and the VSS demonstrated a high correlation (rho = - 0.89). In a s le of 62 patients, the test-retest evaluation showed high correlation (0.74-0.99). Our study supports the Spanish version of the PSAQ as a valid, reliable, and reproducible tool to assess the perception and impact of neck scars in Spanish-speaking patients who undergo head and neck surgery.
Identification of potential early regulators of aphid resistance in Medicago truncatula via transcription factor expression profiling
Publisher: Wiley
Date: 22-03-2010
DOI: 10.1111/J.1469-8137.2010.03229.X
Abstract: *Resistance to aphids has been identified in a number of plant species, yet the molecular mechanisms underlying aphid resistance remain largely unknown. *Using high-throughput quantitative real-time PCR technology, the transcription profiles of 752 putative Medicago truncatula transcription factor genes were analysed in a pair of susceptible and resistant closely related lines of M. truncatula following 6 and 12 h of bluegreen aphid (Acyrthosiphon kondoi) infestation. *Eighty-two transcription factor genes belonging to 30 transcription factor families were responsive to bluegreen aphid infestation. More transcription factor genes were responsive in the resistant interaction than in the susceptible interaction of the 36 genes that were induced at 6 and/or 12 h, 32 were induced only in the resistant interaction. Bluegreen aphid-induced expression of a subset of these genes was correlated with the presence of AKR, a single dominant gene conferring resistance to bluegreen aphids. Similar transcription factor expression patterns of this subset were associated with bluegreen aphid resistance in other M. truncatula genetic backgrounds, as well as with resistance to pea aphid (Acyrthosiphon pisum). *Our results suggest that these transcription factors are among the early aphid-responsive genes in resistant plants, and may play important roles in resistance to multiple aphid species.
A rapid method for profiling of volatile and semi-volatile phytohormones using methyl chloroformate derivatisation and GC–MS
Publisher: Springer Science and Business Media LLC
Date: 08-09-2015
Independent action and contrasting phenotypes of resistance genes against spotted alfalfa aphid and bluegreen aphid in Medicago truncatula
Publisher: Wiley
Date: 17-11-2007
DOI: 10.1111/J.1469-8137.2006.01939.X
Abstract: Host resistance to aphids is poorly understood. Medicago truncatula, a model legume and cultivated pasture species, was used to elucidate defense against two aphid species, Therioaphis trifolii f. maculata (spotted alfalfa aphid, SAA) and Acyrthosiphon kondoi (bluegreen aphid, BGA). Aphid performance and plant damage were compared between near-isogenic cultivars, Mogul and Borung, that differ in resistance to both aphids. Analyses of aphid resistance in Mogul x Borung F2 plants and their progeny revealed modes of action and chromosome locations of resistance genes. Separate genes were identified for SAA resistance (TTR) and BGA resistance (AKR) both mapped to chromosome 3 but were found to act independently to reduce survival and growth of their target aphid species. The TTR locus controls distinct, and contrasting, local and systemic plant responses between the near-isogenic cultivars. TTR-mediated plant responses imply interaction between a resistance factor(s) in vascular tissue and a bioactive component(s) of SAA saliva. Features of both resistance traits suggest homology to aphid resistance in other legumes elucidation of their molecular mechanisms will likely apply to other aphid-plant interactions.
Phoma medicaginis stimulates the induction of the octadecanoid and phenylpropanoid pathways in Medicago truncatula
Publisher: Wiley
Date: 03-01-2012
Interactions between distinct types of DNA binding proteins enhance binding to ocs element promoter sequences
Publisher: JSTOR
Date: 12-1995
DOI: 10.2307/3870165
Characterization of pea aphid resistance in Medicago truncatula
Publisher: Oxford University Press (OUP)
Date: 09-01-2008
Abstract: To achieve a thorough understanding of plant-aphid interactions, it is necessary to investigate in detail both the plant and insect side of the interaction. The pea aphid (PA Acyrthosiphon pisum) has been selected by an international consortium as the model species for genetics and genomics studies, and the model legume Medicago truncatula is a host of this aphid. In this study, we identified resistance to PA in a M. truncatula line, ‘Jester’, with well-characterized resistance to a closely related aphid, the bluegreen aphid (BGA Acyrthosiphon kondoi). The biology of resistance to the two aphid species shared similarity, with resistance in both cases occurring at the level of the phloem, requiring an intact plant and involving a combination of antixenosis, antibiosis, and plant tolerance. In addition, PA resistance cosegregated in ‘Jester’ with a single dominant gene for BGA resistance. These results raised the possibility that both resistances may be mediated by the same mechanism. This was not supported by the results of gene induction studies, and resistance induced by BGA had no effect on PA feeding. Moreover, different genetic backgrounds containing a BGA resistance gene from the same resistance donor differ in resistance to PA. These results suggest that distinct mechanisms are involved in resistance to these two aphid species. Resistance to PA and BGA in the same genetic background in M. truncatula makes this plant an attractive model for the study of both plant and aphid components of resistant and susceptible plant-aphid interactions.
Medicago truncatula as a model host for studying legume infecting rhizoctonia solani and identification of a locus affecting resistance to root canker
Publisher: Wiley
Date: 18-10-2013
Ethylene response factors and their role in plant defence.
Publisher: CABI Publishing
Date: 06-02-2013
Abstract: The APETALA2/Ethylene response factor (AP2/ERF) family of transcription factors (TFs) plays crucial roles in the regulation of gene expression during plant development and in response to biotic and abiotic stress. Although AP2/ERFs have been implicated in a range of plant stress responses, this review focuses on ERFs in the context of the plant response to other organisms, primarily not only pathogenic but also symbiotic. The ERF subfamily is particularly important in the establishment and the tight regulation of plant defences through a balance of positive and negative transcriptional regulation. The expression of the ERFs is induced by pathogens with different lifestyles and they have been implicated in resistance to biotrophs, necrotrophs and hemibiotrophs, but members also play important roles in other plant-microbe interactions, for ex le, nodule formation in legumes. ERFs achieve this, in part, by acting as integrators in the crosstalk between signalling pathways mediated by ethylene (ET), jasmonic acid, salicylic acid and other plant hormones to modulate gene expression according to the stimuli sensed. This review collates recent findings on the regulation of this family of TFs, including transcriptional and post-translational regulation. Although DNA binding is typically conferred through the characteristic AP2 domain, the function of other domains including the EDLL and ERF-associated hiphilic repression (EAR) domains in regulating gene expression is discussed. Finally, the potential for ERFs to be used to enhance resistance to pathogens in crops is considered.
ISOLATION AND CHARACTERIZATION OF 2 RELATED ARABIDOPSIS OCS-ELEMENT BZIP BINDING-PROTEINS
Publisher: Wiley
Date: 10-1993
DOI: 10.1046/J.1365-313X.1993.04040711.X
Abstract: Ocs-elements are a group of related, bipartite promoter elements which have been exploited by two distinct groups of plant pathogens, Agrobacterium and certain viruses to express genes in plants. The genes for two Arabidopsis bZIP (basic region-leucine zipper) proteins that bind to ocs-elements have been isolated and characterized. The genes, called OBF4 and OBF5, were isolated by screening an Arabidopsis genomic library with degenerate oligonucleotides complementary to the DNA-binding domains of other plant ocs-element-binding proteins. The OBF4 and OBF5 proteins show 53% amino acid identity but low DNA homology. Southern blot analysis demonstrated that each of the OBF genes is a member of a small family. OBF4 is more similar to the tobacco TGA1a and Arabidopsis TGA1 proteins, while OBF5 is more similar to the maize OBF3.1, wheat HBP1b and Arabidopsis aHBP1b proteins. The DNA-binding properties of OBF4 and OBF5 were similar although OBF5 was able to bind simultaneously to both halves of the ocs-element more efficiently than OBF4. This difference in binding to the ocs-element between two closely related proteins from the same species is potentially significant since binding to both halves of the ocs-element is a pre-requisite for in vivo transcriptional activity.
Transcription factors in plant defense and stress responses
Publisher: Elsevier BV
Date: 10-2002
DOI: 10.1016/S1369-5266(02)00289-3
Abstract: Transcriptional control of the expression of stress-responsive genes is a crucial part of the plant response to a range of abiotic and biotic stresses. Research carried out in the past few years has been productive in identifying transcription factors that are important for regulating plant responses to these stresses. These studies have also revealed some of the complexity and overlap in the responses to different stresses, and are likely to lead to new ways to enhance crop tolerance to disease and environmental stress.
Aphid resistance in Medicago truncatula involves antixenosis and phloem-specific, inducible antibiosis, and maps to a single locus flanked by NBS-LRR resistance gene analogs
Publisher: Oxford University Press (OUP)
Date: 04-2005
Abstract: Aphids and related insects feed from a single cell type in plants: the phloem sieve element. Genetic resistance to Acyrthosiphon kondoi Shinji (bluegreen aphid or blue alfalfa aphid) has been identified in Medicago truncatula Gaert. (barrel medic) and backcrossed into susceptible cultivars. The status of M. truncatula as a model legume allows an in-depth study of defense against this aphid at physiological, biochemical, and molecular levels. In this study, two closely related resistant and susceptible genotypes were used to characterize the aphid-resistance phenotype. Resistance conditions antixenosis since migratory aphids were deterred from settling on resistant plants within 6 h of release, preferring to settle on susceptible plants. Analysis of feeding behavior revealed the trait affects A. kondoi at the level of the phloem sieve element. Aphid reproduction on excised shoots demonstrated that resistance requires an intact plant. Antibiosis against A. kondoi is enhanced by prior infestation, indicating induction of this phloem-specific defense. Resistance segregates as a single dominant gene, AKR (Acyrthosiphon kondoi resistance), in two mapping populations, which have been used to map the locus to a region flanked by resistance gene analogs predicted to encode the CC-NBS-LRR subfamily of resistance proteins. This work provides the basis for future molecular analysis of defense against phloem parasitism in a plant model system.
A glucocorticoid-inducible transcription system causes severe growth defects in Arabidopsis and induces defense-related genes
Publisher: Wiley
Date: 10-1999
DOI: 10.1046/J.1365-313X.1999.00575.X
Abstract: A glucocorticoid-inducible transcription system was employed to control the expression of AtEBP, an Arabidopsis transcription factor. A number of the transgenic AtEBP lines had developmental and growth defects when grown on dexamethasone (DEX), a strong synthetic glucocorticoid. However, these growth defects were not confined to the AtEBP lines but were observed with other transgenic lines that were generated using the same system, including empty vector lines. In about 25% of the AtEBP or empty vector transgenic lines, these growth defects were severe and in some cases led to death. As AtEBP has been linked to the plant defense response, the expression of specific defense-related genes, including a number of pathogenesis-related (PR) genes was also examined. PDF1.2, a plant defensin gene, was strongly induced in all transgenic lines examined following treatment with DEX, including empty vector lines that did not show any observable DEX-induced growth defect. PR-5 was induced to a lesser extent in all the lines, while the expression of PR-1, PR-2 and phenylalanine ammonia-lyase 3 (PAL3) did not change significantly. While the induction of the AtEBP transgene and PDF1.2 had similar DEX concentration requirements, the kinetics of induction differed significantly, with the AtEBP transgene being induced within 1 h and PDF1.2 only being induced between 24 and 48 h. Although the molecular mechanisms underlying the growth defects and changes in gene expression remain to be determined, these changes appear to result from the glucocorticoid-inducible system itself, and may therefore limit the usefulness of this system for controlling gene expression in Arabidopsis.
The essential role of genetic resources in narrow-leafed lupin improvement
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/CP13092
Abstract: The narrow-leafed lupin (Lupinus angustifolius L.) is a legume with much to offer to agriculture and human wellbeing through its adaptation to nitrogen- and phosphorus-deficient, acid, sandy soils, and production of nutritious, very low glycemic index grain with manifold health benefits. However, the industry has exploited only a small fraction of the genetic and adaptive ersity of the species, reflecting a short and fragmented domestication history. Given declining global production, unlocking the potential residing in untapped sources of genetic ersity to maximise yield and value is critical for the future of the crop. To this end, a wide range of genetic resources is under evaluation. The Australian Lupin Collection comprises almost 4600 erse, mostly wild accessions, many of which have been genotyped using DArT (Diversity Array Technology) markers, and collection sites characterised to facilitate ecophysiology of contrasting material. Additional exotic genetic resources include recombinant inbred line and mutant populations, as well as inter-specific crosses. These resources are being used to investigate specific adaptation and genetic and molecular control of key traits, all of which will be expedited by current efforts to provide a reference genome sequence for L. angustifolius. Genetic base broadening is the current breeding focus, combining distantly related wild and domestic material with elite cultivars in double-backcrosses or topcrosses, with dramatic effects on yield. In future this will be complemented by marker-based, targeted trait introgression to improve narrow-leafed lupin adaptation, quality/value, and fit into the farming system.
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