Now showing 1 - 4 of 4
  • Publication
    A wheat NAC interacts with an orphan protein and enhances resistance to Fusarium head blight disease
    Taxonomically-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.
      253Scopus© Citations 35
  • Publication
    A wheat cytochrome P450 enhances both resistance to deoxynivalenol and grain yield
    The mycotoxin deoxynivalenol (DON) serves as a plant disease virulence factor for the fungi Fusarium graminearum and F. culmorum during the development of Fusarium head blight (FHB) disease on wheat. A wheat cytochrome P450 gene from the subfamily CYP72A, TaCYP72A, was cloned from wheat cultivar CM82036. TaCYP72A was located on chromosome 3A with homeologs present on 3B and 3D of the wheat genome. Using gene expression studies, we showed that TaCYP72A variants were activated in wheat spikelets as an early response to F. graminearum, and this activation was in response to the mycotoxic Fusarium virulence factor deoxynivalenol (DON). Virus induced gene silencing (VIGS) studies in wheat heads revealed that this gene family contributes to DON resistance. VIGS resulted in more DON-induced discoloration of spikelets, as compared to mock VIGS treatment. In addition to positively affecting DON resistance, TaCYP72A also had a positive effect on grain number. VIGS of TaCYP72A genes reduced grain number by more than 59%. Thus, we provide evidence that TaCYP72A contributes to host resistance to DON and conclude that this gene family warrants further assessment as positive contributors to both biotic stress resistance and grain development in wheat.
      265Scopus© Citations 38
  • Publication
    The wheat SnRK1α family and its contribution to Fusarium toxin tolerance
    Deoxynivalenol (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.
      368Scopus© Citations 17
  • Publication
    Virus-induced gene silencing (VIGS) for functional characterization of disease resistance genes in barley seedlings
    With 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.
      491Scopus© Citations 5