17 research outputs found
Signalisation calcium chez les plantes : identification et caractérisation de partenaires de CML9, une protéine réceptrice des signaux calciques, impliquée dans les réponses aux stress de l'environnement chez Arabidopsis thaliana
No full textLes plantes utilisent le calcium comme messager intracellulaire pour adapter leur développement aux fluctuations de l'environnement. Parmi les protéines assurant la conversion de signaux calciques en réponses biologiques, CML9, une représentante des calmodulines chez Arabidopsis thaliana, avait été identifiée comme une protéine régulatrice, des réactions de défense à des agents pathogènes, et du contrôle de la germination par l'acide abscissique. En vue d'identifier les processus cellulaires modulés par CML9, la recherche de ses cibles protéiques a conduit à isoler diverses protéines parmi lesquelles le facteur de transcription PRR2. L'analyse des caractéristiques d'interaction entre CML9 et PRR2 a révélé la spécificité de l'interaction ainsi que l'association physique des deux protéines dans les cellules végétales. L'étude de lignées mutantes, altérées dans l'expression de CML9 et PRR2, suggère un rôle similaire des deux protéines dans les réactions de défense ainsi que dans la régulation de la germination, contribuant à établir les bases d'une nouvelle voie de signalisation calcique associée à divers contextes physiologiques.Plants use calcium as an intracellular signal to adapt their development in response to environmental fluctuations. Calcium signals are converted into biological responses by calcium sensors such as calmodulin, a calcium-binding protein conserved in all eukaryotes. CML9, a calmodulin-related protein, was recently identified as a regulatory component of plant responses against pathogens and the control of germination by abscisic acid in Arabidopsis thaliana. To identify the mechanisms by which CML9 exerts this role, searches for CML9-binding proteins allowed to isolate proteins with diverse functions and, PRR2 a previously uncharacterized transcription factor was further studied. Analysis of CML9/PRR2 binding properties revealed a specific physical interaction between the two proteins in plant cells. Through the characterization of mutants with reduced levels in PRR2 expression or lacking CML9 function, the two proteins were found to play similar roles in defence responses and the control of germination, thus providing evidence for a new calcium signalling pathway associated to these physiological contexts
Trichothecenes and Fumonisins: Key Players in <i>Fusarium</i>–Cereal Ecosystem Interactions
No full textFusarium fungi produce a diverse array of mycotoxic metabolites during the pathogenesis of cereals. Some, such as the trichothecenes and fumonisins, are phytotoxic, acting as non-proteinaceous effectors that facilitate disease development in cereals. Over the last few decades, we have gained some depth of understanding as to how trichothecenes and fumonisins interact with plant cells and how plants deploy mycotoxin detoxification and resistance strategies to defend themselves against the producer fungi. The cereal-mycotoxin interaction is part of a co-evolutionary dance between Fusarium and cereals, as evidenced by a trichothecene-responsive, taxonomically restricted, cereal gene competing with a fungal effector protein and enhancing tolerance to the trichothecene and resistance to DON-producing F. graminearum. But the binary fungal–plant interaction is part of a bigger ecosystem wherein other microbes and insects have been shown to interact with fungal mycotoxins, directly or indirectly through host plants. We are only beginning to unravel the extent to which trichothecenes, fumonisins and other mycotoxins play a role in fungal-ecosystem interactions. We now have tools to determine how, when and where mycotoxins impact and are impacted by the microbiome and microfauna. As more mycotoxins are described, research into their individual and synergistic toxicity and their interactions with the crop ecosystem will give insights into how we can holistically breed for and cultivate healthy crops
Transcriptional Profiling Reveals the Wheat Defences against Fusarium Head Blight Disease Regulated by a NAC Transcription Factor
No full textThe wheat NAC transcription factor TaNACL-D1 enhances resistance to the economically devastating Fusarium head blight (FHB) disease. The objective of this study was to decipher the alterations in gene expression, pathways and biological processes that led to enhanced resistance as a result of the constitutive expression of TaNACL-D1 in wheat. Transcriptomic analysis was used to determine the genes and processes enhanced in wheat due to TaNACL-D1 overexpression, both in the presence and absence of the causal agent of FHB, Fusarium graminearum (0- and 1-day post-treatment). The overexpression of TaNACL-D1 resulted in more pronounced transcriptional reprogramming as a response to fungal infection, leading to the enhanced expression of genes involved in detoxification, immune responses, secondary metabolism, hormone biosynthesis, and signalling. The regulation and response to JA and ABA were differentially regulated between the OE and the WT. Furthermore, the results suggest that the OE may more efficiently: (i) regulate the oxidative burst; (ii) modulate cell death; and (iii) induce both the phenylpropanoid pathway and lignin synthesis. Thus, this study provides insights into the mode of action and downstream target pathways for this novel NAC transcription factor, further validating its potential as a gene to enhance FHB resistance in wheat
Interaction of a plant pseudo-response regulator with a calmodulin-like protein
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Virus-induced gene silencing (VIGS) for functional characterization of disease resistance genes in barley seedlings
No full textWith the recent advances in sequencing technologies, many studies are generating lists of candidate genes associated with specific traits. The major bottleneck in functional genomics is the validation of gene function. This is achieved by analyzing the effect of either gene silencing or overexpression on a specific phenotypic or biochemical trait. This usually requires the generation of stable transgenic plants and this can take considerable time. Therefore any technique that expedites the validation of gene function is of particular benefit in cereals, including barley. One such technique is Virus-Induced Gene Silencing (VIGS), which evokes a natural antiviral defense mechanism in plants. VIGS can be used to downregulate gene expression in a transient manner, but long enough to determine its effects on a specific phenotype. It is particularly useful for screening candidate genes and selecting those with potential for disease control. VIGS based on Barley Stripe Mosaic Virus (BSMV) is a powerful and efficient tool for the analysis of gene function in cereals. Here we present a BSMV VIGS protocol for simple and robust gene silencing in barley and describe it to evaluate the role of the hormone receptor BRI1 (Brassinosteroid Insensitive 1) in barley leaf resistance to Fusarium infection.Department of Agriculture, Food and the MarineScience Foundation IrelandChanged item type from journal article to book - ACUnsure of item version so applied 12 month embargo - A
The wheat SnRK1α family and its contribution to Fusarium toxin tolerance
No full textDeoxynivalenol (DON) is a mycotoxin produced by phytopathogenic Fusarium fungi in cereal grain and plays a role as a disease virulence factor. TaFROG (Triticum aestivum Fusarium Resistance Orphan Gene) enhances wheat resistance to DON and it interacts with a sucrose non-fermenting-1 (SNF1)-related protein kinase 1 catalytic subunit α (SnRK1α). This protein kinase family is central integrator of stress and energy signalling, regulating plant metabolism and growth. Little is known regarding the role of SnRK1α in the biotic stress response, especially in wheat. In this study, 15 wheat (Triticum aestivum) SnRK1α genes (TaSnRK1αs) belonging to four homoeologous groups were identified in the wheat genome. TaSnRK1αs are expressed ubiquitously in all organs and developmental stages apart from two members predominantly detected in grain. While DON treatment had either no effect or downregulated the transcription of TaSnRK1αs, it increased both the kinase activity associated with SnRK1α and the level of active (phosphorylated) SnRK1α. Down-regulation of two TaSnRK1αs homoeolog groups using virus induced gene silencing (VIGS) increased the DON-induced damage of wheat spikelets. Thus, we demonstrate that TaSnRK1αs contribute positively to wheat tolerance of DON and conclude that this gene family may provide useful tools for the improvement of crop biotic stress resistance.Science Foundation IrelandIrish Department of AgricultureBiotechnological and Biological Sciences Research Council of the United KingdomDesigning Future Wheat (DFW) strategic programmeupdate copyright and citation details during checkdate report - A
Supplemental Material for Vranic et al., 2022
No full textDE_dataset_Vranic_et_al.xlsx contains expression profiles of wheat transcripts during an infection with five fungal diseases (Fusarium head blight, Fusarium crown rot, Septoria tritici blotch, stripe rust, powdery mildew. Only the data of high confidence wheat genes were retained (FDR < 0.05; -1 ≥ Log2 Fold Change ≥1). The source of the raw counts and a methodology of the differential expression analysis are described in Benbow et al. (2019) https://doi.org/10.1534/g3.119.400444
CML9, a multifunctional Arabidopsis thaliana calmodulin-like protein involved in stress responses and plant growth?
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A wheat NAC interacts with an orphan protein and enhances resistance to Fusarium head blight disease
No full textTaxonomically-restricted orphan genes play an important role in environmental adaptation, as recently demonstrated by the fact that the Pooideae-specific orphan TaFROG (Triticum aestivum Fusarium Resistance Orphan Gene) enhanced wheat resistance to the economically devastating Fusarium head blight (FHB) disease. Like most orphan genes, little is known about the cellular function of the encoded protein TaFROG, other than it interacts with the central stress regulator TaSnRK1α. Here, we functionally characterized a wheat (T. aestivum) NAC-like transcription factor TaNACL-D1 that interacts with TaFROG and investigated its' role in FHB using studies to assess motif analyses, yeast transactivation, protein-protein interaction, gene expression and the disease response of wheat lines overexpressing TaNACL-D1. TaNACL-D1 is a Poaceae-divergent NAC transcription factor that encodes a Triticeae-specific protein C-terminal region with transcriptional activity and a nuclear localisation signal. The TaNACL-D1/TaFROG interaction was detected in yeast and confirmed in planta, within the nucleus. Analysis of multi-protein interactions indicated that TaFROG could form simultaneously distinct protein complexes with TaNACL-D1 and TaSnRK1α in planta. TaNACL-D1 and TaFROG are co-expressed as an early response to both the causal fungal agent of FHB, Fusarium graminearum and its virulence factor deoxynivalenol (DON). Wheat lines overexpressing TaNACL-D1 were more resistant to FHB disease than wild type plants. Thus, we conclude that the orphan protein TaFROG interacts with TaNACL-D1, a NAC transcription factor that forms part of the disease response evolved within the Triticeae.Science Foundation IrelandUpdate citation details at check date - H
