S14 - Session O6 - Epigenetics of long-lasting post-harvest resistance in tomato

Authors: Katie Stevens *, Victoria Pastor, Marco Catoni, Estrella Luna Diez

Tomato is a major crop world-wide with an annual retail value in the UK of £175 million, however its production is heavily limited by Botrytis cinerea, the causal agent of grey mould. Due to the toxicity of post-harvest pesticide application, alternative control methods are required. An attractive method for future integrated disease management is priming, a phenomenon that sensitises defence mechanisms for a faster, more efficient defence response upon subsequent attack. Priming typically resulting in broad spectrum resistance at minimal cost. In tomato fruit we have demonstrated that priming by the chemical β-aminobutyric acid results in long lasting resistance against B. cinerea . Priming is associated with epigenetic changes such as DNA methylation which ultimately alter gene expression. Our work has shown that priming seedlings (2 weeks old) results in both long lasting and transgenerational resistance which is not observed when BABA treatments are applied to older plants (12 weeks). This work explores how changes in DNA methylation mark long lasting priming in fruit and explores the hypothesis that young plants display a greater epigenetic imprinting capacity. Using whole genome bisulphite sequencing analysis (WGBS), changes in DNA methylation were observed depending on the timing of priming stimuli. Differentially methylated regions (DMRs) specific to the phenotype of long-lasting resistance have been identified. Our results illustrate that BABA treatment impacts CHH context methylation depending on timepoint of application. Additionally, CHH methylation is revealed to be highly dynamic over time. Furthermore, a transcriptomic analysis on B. cinerea infected fruit from early and late BABA treated plants identified differentially expressed genes (DEGs) associated with resistance against B. cinerea . By overlapping our DEGs of interest with our resistance associated DMRs we aim to ultimately identify markers of long-lasting priming in tomato fruit which could serve for targets of durable resistance in other cultivars or crop species.