Activation of plant defence responses requires significant transcriptional reprogramming to mount an effective response to pathogens. This response must be finely balanced with growth and development processes to ensure optimal allocation of cellular resources. A fundamental mechanism of gene expression regulation is covalent modification of histones. Histone acetyltransferases (HATs) and histone deacetylases (HDACs) antagonistically control the acetylation levels of histones at specific genomic loci to ultimately affect gene expression. This thesis focuses on histone acetylation as a mechanism by which plants mount an effective immune response. In Chapter 3, a reverse genetic screen of Arabidopsis HAT mutants is presented where a negative regulator (HAM2) of defence against the plant pathogen Pto DC3000 was identified. Whilst mutants of the negative regulator (ham2 ) demonstrate enhanced resistance to P. syringae, their susceptibility to the necrotrophic pathogen B. cinerea is unchanged. Alongside the immunity phenotype, ham2 plants exhibit increased adult leaf surface area, fresh weight and root length. Since ham2 is the only known Arabidopsis mutant with increased immunity and growth, it represents a promising target in an agricultural context. In Chapter 4, homology models of A. thaliana, B. napus and S. lycopersicum HAM2 proteins were created, supported by a series of cheminformatics and in silico docking methods, to identify chemical inhibitors for future agricultural applications. Finally, the role of Arabidopsis HATs in effector-triggered immunity was investigated in Chapter 5. Here, HAG1 was identified as a key positive regulator of effector-triggered responses. Overall, this thesis contributes to our understanding of the role of HAM2 and HAG1 histone acetyltransferases in plant immunity, and presents HAM2 as a novel target in an agricultural context.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:742249 |
| Date | January 2017 |
| Creators | Kancy, Stephanie Jayne Thorley |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/102601/ |
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