Anthony Gendall

Multiple Roles of Arabidopsis VRN1 in Vernalization and Flowering Time Control

Publisher: American Association for the Advancement of Science (AAAS)

Date: 12-07-2002

DOI: 10.1126/SCIENCE.1072147

Abstract: Arabidopsis VRN genes mediate vernalization, the process by which a long period of cold induces a mitotically stable state that leads to accelerated flowering during later development. VRN1 encodes a protein that binds DNA in vitro in a non–sequence-specific manner and functions in stable repression of the major target of the vernalization pathway, the floral repressor FLC . Overexpression of VRN1 reveals a vernalization-independent function for VRN1 , mediated predominantly through the floral pathway integrator FT , and demonstrates that VRN1 requires vernalization-specific factors to target FLC .

The PHD Finger Protein VRN5 Functions in the Epigenetic Silencing of Arabidopsis FLC

Publisher: Elsevier BV

Date: 2007

DOI: 10.1016/J.CUB.2006.11.052

Abstract: Vernalization, the acceleration of flowering by the prolonged cold of winter, ensures that plants flower in favorable spring conditions. During vernalization in Arabidopsis, cold temperatures repress FLOWERING LOCUS C (FLC) expression in a mechanism involving VERNALIZATION INSENSITIVE 3 (VIN3), and this repression is epigenetically maintained by a Polycomb-like chromatin regulation involving VERNALIZATION 2 (VRN2), a Su(z)12 homolog, VERNALIZATION 1 (VRN1), and LIKE-HETEROCHROMATIN PROTEIN 1. In order to further elaborate how cold repression triggers epigenetic silencing, we have targeted mutations that result in FLC misexpression both at the end of the prolonged cold and after subsequent development. This identified VERNALIZATION 5 (VRN5), a PHD finger protein and homolog of VIN3. Our results suggest that during the prolonged cold, VRN5 and VIN3 form a heterodimer necessary for establishing the vernalization-induced chromatin modifications, histone deacetylation, and H3 lysine 27 trimethylation required for the epigenetic silencing of FLC. Double mutant and FLC misexpression analyses reveal additional VRN5 functions, both FLC-dependent and -independent, and indicate a spatial complexity to FLC epigenetic silencing with VRN5 acting as a common component in multiple pathways.

Draft Genome Sequence of Enterobacter asburiae NCR1, a Plant Growth-Promoting Rhizobacterium Isolated from a Cadmium-Contaminated Environment

Publisher: American Society for Microbiology

Date: 02-09-2021

DOI: 10.1128/MRA.00478-21

Abstract: Enterobacter asburiae NCR1 is a plant growth-promoting rhizobacterium isolated from the rhizosphere of Carpobrotus rossii . We report the draft genome sequence of E. asburiae strain NCR1, which revealed many genes facilitating beneficial interactions with plant hosts.

Analysis of the Molecular Basis of Flowering Time Variation in Arabidopsis Accessions  

Publisher: Oxford University Press (OUP)

Date: 06-2003

DOI: 10.1104/PP.103.021212

Abstract: Allelic variation at the FRI (FRIGIDA) and FLC (FLOWERING LOCUS C) loci are major determinants of flowering time in Arabidopsis accessions. Dominant alleles of FRI confer a vernalization requirement causing plants to overwinter vegetatively. Many early flowering accessions carry loss-of-function fri alleles containing one of two deletions. However, some accessions categorized as early flowering types do not carry these deletion alleles. We have analyzed the molecular basis of earliness in five of these accessions: Cvi, Shakhdara, Wil-2, Kondara, and Kz-9. The Cvi FRI allele carries a number of nucleotide differences, one of which causes an in-frame stop codon in the first exon. The other four accessions contain nucleotide differences that only result in amino acid substitutions. Preliminary genetic analysis was consistent with Cvi carrying a nonfunctional FRI allele Wil-2 carrying either a defective FRI or a dominant suppressor of FRI function and Shakhdara, Kondara, and Kz-9 carrying a functional FRI allele with earliness being caused by allelic variation at other loci including FLC. Allelic variation at FLC was also investigated in a range of accessions. A novel nonautonomous Mutator-like transposon was found in the weak FLC allele in Landsberg erecta, positioned in the first intron, a region required for normal FLC regulation. This transposon was not present in FLC alleles of most other accessions including Shakhdara, Kondara, or Kz-9. Thus, variation in Arabidopsis flowering time has arisen through the generation of nonfunctional or weak FRI and FLC alleles.

Towards novel herbicide modes of action by inhibiting lysine biosynthesis in plants

Publisher: eLife Sciences Publications, Ltd

Date: 27-07-2021

DOI: 10.7554/ELIFE.69444

Abstract: Weeds are becoming increasingly resistant to our current herbicides, posing a significant threat to agricultural production. Therefore, new herbicides with novel modes of action are urgently needed. In this study, we exploited a novel herbicide target, dihydrodipicolinate synthase (DHDPS), which catalyses the first and rate-limiting step in lysine biosynthesis. The first class of plant DHDPS inhibitors with micromolar potency against Arabidopsis thaliana DHDPS was identified using a high-throughput chemical screen. We determined that this class of inhibitors binds to a novel and unexplored pocket within DHDPS, which is highly conserved across plant species. The inhibitors also attenuated the germination and growth of A. thaliana seedlings and confirmed their pre-emergence herbicidal activity in soil-grown plants. These results provide proof-of-concept that lysine biosynthesis represents a promising target for the development of herbicides with a novel mode of action to tackle the global rise of herbicide-resistant weeds.

Acceleration of flowering in Arabidopsis thaliana by Cape Verde Islands alleles of FLOWERING H is dependent on the floral promoter FD

Publisher: Oxford University Press (OUP)

Date: 10-05-2013

DOI: 10.1093/JXB/ERT120

A dual-target herbicidal inhibitor of lysine biosynthesis

Publisher: eLife Sciences Publications, Ltd

Date: 20-06-2022

DOI: 10.7554/ELIFE.78235

Abstract: Herbicides with novel modes of action are urgently needed to safeguard global agricultural industries against the damaging effects of herbicide-resistant weeds. We recently developed the first herbicidal inhibitors of lysine biosynthesis, which provided proof-of-concept for a promising novel herbicide target. In this study, we expanded upon our understanding of the mode of action of herbicidal lysine biosynthesis inhibitors. We previously postulated that these inhibitors may act as proherbicides. Here, we show this is not the case. We report an additional mode of action of these inhibitors, through their inhibition of a second lysine biosynthesis enzyme, and investigate the molecular determinants of inhibition. Furthermore, we extend our herbicidal activity analyses to include a weed species of global significance.

Genetic Diversity, Population Structure and Ancestral Origin of Australian Wheat

Publisher: Frontiers Media SA

Date: 12-12-2017

DOI: 10.3389/FPLS.2017.02115

The VERNALIZATION 2 Gene Mediates the Epigenetic Regulation of Vernalization in Arabidopsis

Publisher: Elsevier BV

Date: 11-2001

DOI: 10.1016/S0092-8674(01)00573-6

Abstract: The acceleration of flowering by a long period of low temperature, vernalization, is an adaptation that ensures plants overwinter before flowering. Vernalization induces a developmental state that is mitotically stable, suggesting that it may have an epigenetic basis. The VERNALIZATION2 (VRN2) gene mediates vernalization and encodes a nuclear-localized zinc finger protein with similarity to Polycomb group (PcG) proteins of plants and animals. In wild-type Arabidopsis, vernalization results in the stable reduction of the levels of the floral repressor FLC. In vrn2 mutants, FLC expression is downregulated normally in response to vernalization, but instead of remaining low, FLC mRNA levels increase when plants are returned to normal temperatures. VRN2 function therefore stably maintains FLC repression after a cold treatment, serving as a mechanism for the cellular memory of vernalization.

Two Endosomal NHX-Type Na+/H+ Antiporters are Involved in Auxin-Mediated Development in Arabidopsis thaliana

Publisher: Oxford University Press (OUP)

Date: 16-05-2018

DOI: 10.1093/PCP/PCY090

Abstract: In Arabidopsis thaliana, the endosomal-localized Na+/H+ antiporters NHX5 and NHX6 regulate ion and pH homeostasis and are important for plant growth and development. However, the mechanism by which these endosomal NHXs function in plant development is not well understood. Auxin modulates plant growth and development through the formation of concentration gradients in plant tissue to control cell ision and expansion. Here, we identified a role for NHX5 and NHX6 in the establishment and maintenance of auxin gradients in embryo and root tissues. We observed developmental impairment and abnormal cell ision in embryo and root tissues in the double knockout nhx5 nhx6, consistent with these tissues showing high expression of NHX5 and NHX6. Through confocal microscopy imaging with the DR5::GFP auxin reporter, we identify defects in the perception, accumulation and redistribution of auxin in nhx5 nhx6 cells. Furthermore, we find that the steady-state levels of the PIN-FORMED (PIN) auxin efflux carriers PIN1 and PIN2 are reduced in nhx5 nhx6 root cells. Our results demonstrate that NHX5 and NHX6 function in auxin-mediated plant development by maintaining PIN abundance at the plasma membrane, and provide new insight into the regulation of plant development by endosomal NHX antiporters.

A dual-target herbicidal inhibitor of lysine biosynthesis

Publisher: Cold Spring Harbor Laboratory

Date: 04-03-2022

DOI: 10.1101/2022.03.04.482975

Abstract: Herbicides with novel modes of action are urgently needed to safeguard global agricultural industries against the damaging effects of herbicide-resistant weeds. We recently developed the first herbicidal inhibitors of lysine biosynthesis, which provided proof-of-concept for a promising novel herbicide target (Soares da Costa et al., 2021). In this study, we expanded upon our understanding of the mode of action of herbicidal lysine biosynthesis inhibitors. We previously postulated that these inhibitors may act as proherbicides (Soares da Costa et al., 2021). Here we show this is not the case. We report an additional mode of action of these inhibitors, through their inhibition of a second lysine biosynthesis enzyme, and investigate the molecular determinants of inhibition. Furthermore, we extend our herbicidal activity analyses to include a weed species of global significance.

Molecular evolution of an oligomeric biocatalyst functioning in lysine biosynthesis.

Publisher: Springer Science and Business Media LLC

Date: 05-12-2017

DOI: 10.1007/S12551-017-0350-Y

Molecular characterisation and genetic mapping of candidate genes for qualitative disease resistance in perennial ryegrass (Lolium perenne L.)

Publisher: Springer Science and Business Media LLC

Date: 19-05-2009

DOI: 10.1186/1471-2229-9-62

Abstract: Qualitative pathogen resistance in both dicotyledenous and monocotyledonous plants has been attributed to the action of resistance (R) genes, including those encoding nucleotide binding site – leucine rich repeat (NBS-LRR) proteins and receptor-like kinase enzymes. This study describes the large-scale isolation and characterisation of candidate R genes from perennial ryegrass. The analysis was based on the availability of an expressed sequence tag (EST) resource and a functionally-integrated bioinformatics database. Amplification of R gene sequences was performed using template EST data and information from orthologous candidate using a degenerate consensus PCR approach. A total of 102 unique partial R genes were cloned, sequenced and functionally annotated. Analysis of motif structure and R gene phylogeny demonstrated that Lolium R genes cluster with putative ortholoci, and evolved from common ancestral origins. Single nucleotide polymorphisms (SNPs) predicted through resequencing of licons from the parental genotypes of a genetic mapping family were validated, and 26 distinct R gene loci were assigned to multiple genetic maps. Clusters of largely non-related NBS-LRR genes were located at multiple distinct genomic locations and were commonly found in close proximity to previously mapped defence response (DR) genes. A comparative genomics analysis revealed the co-location of several candidate R genes with disease resistance quantitative trait loci (QTLs). This study is the most comprehensive analysis to date of qualitative disease resistance candidate genes in perennial ryegrass. SNPs identified within candidate genes provide a valuable resource for mapping in various ryegrass pair cross-derived populations and further germplasm analysis using association genetics. In parallel with the use of specific pathogen virulence races, such resources provide the means to identify gene-for-gene mechanisms for multiple host pathogen-interactions and ultimately to obtain durable field-based resistance.

Vernalization.

Publisher: CABI Publishing

Date: 2006

DOI: 10.1079/9781845930424.0026

NHX-type Na

Publisher: The Company of Biologists

Date: 2019

DOI: 10.1242/JCS.226472

Abstract: The regulation of ion and pH homeostasis of endomembrane organelles is critical for functional protein trafficking, sorting and modification in eukaryotic cells. pH homeostasis is maintained through the activity of vacuolar H

Draft Genome Sequence of Enterobacter mori Strain NSE2, Isolated from the Rhizosphere of a Sedum sp.

Publisher: American Society for Microbiology

Date: 26-08-2021

DOI: 10.1128/MRA.00487-21

Abstract: Enterobacter mori is an important plant pathogen. Here, we report the draft genome sequence of the plant-associated strain Enterobacter mori NSE2, which was found to harbor genes for promotive and pathogenic interactions with plants.

Author response: Towards novel herbicide modes of action by inhibiting lysine biosynthesis in plants

Publisher: eLife Sciences Publications, Ltd

Date: 20-07-2021

DOI: 10.7554/ELIFE.69444.SA2

Towards Novel Herbicide Modes of Action by Inhibiting Lysine Biosynthesis in Plants

Publisher: Cold Spring Harbor Laboratory

Date: 06-05-2021

DOI: 10.1101/2021.05.06.442928

Abstract: Weeds are becoming increasingly resistant to our current herbicides, posing a significant threat to agricultural production. Therefore, new herbicides are urgently needed. In this study, we exploited a novel herbicide target, dihydrodipicolinate synthase (DHDPS), which catalyses the first and rate-limiting step in lysine biosynthesis. Using a high throughput chemical screen, we identified the first class of plant DHDPS inhibitors that have micromolar potency against Arabidopsis thaliana DHDPS isoforms. Employing X-ray crystallography, we determined that this class of inhibitors binds to a novel and unexplored pocket within DHDPS, which is highly conserved across plant species. We also demonstrated that the inhibitors attenuated the germination and growth of A. thaliana seedlings and confirmed their pre-emergence herbicidal activity in soil-grown plants. These results provide proof-of-concept that lysine biosynthesis represents a promising target for the development of herbicides with a novel mode of action to tackle the global rise of herbicide resistant weeds.

When to Switch to Flowering

Publisher: Annual Reviews

Date: 11-1999

DOI: 10.1146/ANNUREV.CELLBIO.15.1.519

Abstract: ▪ Abstract At a certain stage in their life cycle, plants switch from vegetative to reproductive development. This transition is regulated by multiple developmental and environmental cues. These ensure that the plant switches to flowering at a time when sufficient internal resources have been accumulated and the environmental conditions are favorable. The use of a molecular genetic approach in Arabidopsis has resulted in the identification and cloning of many of the genes involved in regulating floral transition. The current view on the molecular function of these genes, their ision into different genetic pathways, and how the pathways interact in a complex regulatory network are summarized.

Using transcriptomics to identify differential gene expression in response to salinity among Australian Phragmites australis clones

Publisher: Frontiers Media SA

Date: 13-04-2016

DOI: 10.3389/FPLS.2016.00432

Arabidopsis Intracellular NHX-Type Sodium-Proton Antiporters are Required for Seed Storage Protein Processing

Publisher: Oxford University Press (OUP)

Date: 28-09-2015

DOI: 10.1093/PCP/PCV138

Abstract: The Arabidopsis intracellular sodium-proton exchanger (NHX) proteins AtNHX5 and AtNHX6 have a well-documented role in plant development, and have been used to improve salt tolerance in a variety of species. Despite evidence that intracellular NHX proteins are important in vacuolar trafficking, the mechanism of this role is poorly understood. Here we show that NHX5 and NHX6 are necessary for processing of the predominant seed storage proteins, and also influence the processing and activity of a vacuolar processing enzyme. Furthermore, we show by yeast two-hybrid and bimolecular fluorescence complementation (BiFC) technology that the C-terminal tail of NHX6 interacts with a component of Retromer, another component of the cell sorting machinery, and that this tail is critical for NHX6 activity. These findings demonstrate that NHX5 and NHX6 are important in processing and activity of vacuolar cargo, and suggest a mechanism by which NHX intracellular (IC)-II antiporters may be involved in subcellular trafficking.

Identification and characterization of orthologs of AtNHX5 and AtNHX6 in Brassica napus

Publisher: Frontiers Media SA

Date: 2012

DOI: 10.3389/FPLS.2012.00208

Author response: A dual-target herbicidal inhibitor of lysine biosynthesis

Publisher: eLife Sciences Publications, Ltd

Date: 08-06-2022

DOI: 10.7554/ELIFE.78235.SA2

Sodium chloride decreases cadmium accumulation and changes the response of metabolites to cadmium stress in the halophyte Carpobrotus rossii

Publisher: Oxford University Press (OUP)

Date: 18-05-2018

DOI: 10.1093/AOB/MCY077

Trafficking to the seed protein storage vacuole

Publisher: CSIRO Publishing

Date: 2018

DOI: 10.1071/FP17318

Abstract: The processing and subcellular trafficking of seed storage proteins is a critical area of physiological, agricultural and biotechnological research. Trafficking to the lytic vacuole has been extensively discussed in recent years, without substantial distinction from trafficking to the protein storage vacuole (PSV). However, despite some overlap between these pathways, there are several ex les of unique processing and machinery in the PSV pathway. Moreover, substantial new data has recently come to light regarding the important players in this pathway, in particular, the intracellular NHX proteins and their role in regulating lumenal pH. In some cases, these new data are limited to genetic evidence, with little mechanistic understanding. As such, the implications of these data in the current paradigm of PSV trafficking is perhaps yet unclear. Although it has generally been assumed that the major classes of storage proteins are trafficked via the same pathway, there is mounting evidence that the 12S globulins and 2S albumins may be trafficked independently. Advances in identification of vacuolar targeting signals, as well as an improved mechanistic understanding of various vacuolar sorting receptors, may reveal the differences in these trafficking pathways.

Comparison of genome structure between white clover and Medicago truncatula supports homoeologous group nomenclature based on conserved synteny

Publisher: Canadian Science Publishing

Date: 11-2008

DOI: 10.1139/G08-076

Abstract: Computational analysis has been used to align the genetic map of white clover ( Trifolium repens L.) with the draft genome sequence of the model legume species Medicago truncatula Gaertn. In silico comparison based on white clover expressed sequence tags that contain simple sequence repeat loci revealed substantial macrosynteny between the genomes of these two species, which are closely related within the Trifolieae tribe of the Fabaceae family. Six of the eight homoeologous chromosome groups (HGs) of allotetraploid white clover show predominant relationships with single M. truncatula (Mt) chromosomes, while the two remaining groups may have participated in an evolutionary reciprocal translocation event. On this basis, a new chromosome nomenclature system for allotetraploid white clover is proposed such that HG A = 3, HG B = 8, HG C = 7, HG D = 4, HG E = 1, HG F = 2, HG G = 5, and HG H = 6. A rationalized linkage map ordering system has also been demonstrated. Improved knowledge of the relationships between agricultural and model forage legume genomes will facilitate prediction of gene location for key agronomic traits for pasture production.

Isolation and characterization of a leukemia inhibitory factor-independent embryonic stem cell line

Publisher: Elsevier BV

Date: 05-1997

DOI: 10.1016/S1357-2725(96)00099-4

Abstract: Leukemia inhibitory factor (LIF) is a mammalian cytokine that has a wide range of physiological activities, including the inhibition of differentiation of embryonic stem (ES) cells. We have used insertional mutagenesis in an attempt to isolate molecules that participate in LIF signal transduction via the LIF receptor. Using a robust screen for undifferentiated cells, we have isolated one ES cell line, Poly 27, that does not require exogenous LIF to remain undifferentiated in vitro. We present evidence that Poly 27 is not irreversibly committed to an undifferentiated phenotype, but can differentiate in vitro if cultured in the presence of chemical differentiating agents, while in syngeneic mice Poly 27 cells form tumours which are composed largely of undifferentiated cells. We have characterized the mechanism of factor independence in Poly 27, and shown it to be a result of autocrine LIF production. This LIF production is potentially the result of a mutation in a gene critically involved in regulating LIF production in ES cells.

The University Of Western Australia Faculty Of Science

Location: Australia

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La Trobe University

Location: Australia

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University Of Melbourne

Location: Australia

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Discovery Projects - Grant ID: DP0210592

Start Date: 2002

End Date: 12-2006

Amount: $25,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0883273

Start Date: 07-2008

End Date: 06-2012

Amount: $90,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0989920

Start Date: 2009

End Date: 12-2009

Amount: $750,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0449651

Start Date: 02-2004

End Date: 02-2007

Amount: $300,000.00

Funder: Australian Research Council

Industrial Transformation Research Hubs - Grant ID: IH180100006

Start Date: 07-2019

End Date: 07-2024

Amount: $4,995,391.00

Funder: Australian Research Council

Industrial Transformation Research Hubs - Grant ID: IH190100022

Start Date: 08-2020

End Date: 08-2025

Amount: $4,787,259.00

Funder: Australian Research Council