The epigenetic control of the establishment and transmission of long-term priming in tomato

Stevens, Katie (2024). The epigenetic control of the establishment and transmission of long-term priming in tomato. University of Birmingham. Ph.D.

Preview

Stevens2024PhD.pdf
Text - Accepted Version
Available under License All rights reserved.
Download (12MB) | Preview

Abstract

Tomato (Solanum lycopersicum) is a major crop world-wide however its production is heavily limited by fungal pathogens such as Botrytis cinerea. Due to the toxicity of postharvest pesticide application, alternative control methods such as priming are being investigated. Here, it is demonstrated that priming with the broad acting elicitor β -amino butyric acid (BABA) results in long-lasting induced resistance (IR) in fruit and progeny of tomato plants only when initiated at an early developmental stage. Whole genome bisulfite sequencing analysis revealed seedling-specific changes, which occurred in the context of lower global CHH methylation levels. Large differences were observed in the transcriptome and methylome following early and late BABA-treatments suggesting a greater epigenetic imprinting capacity of young plants. Importantly, grafting experiments demonstrated that BABA-IR is transmissible from primed rootstocks to unprimed scions. In these resistant scions, a subset of mobile 24 nt small RNAs associated with genes were identified which display an enhanced expression in response to B. cinerea infection in fruit. These results suggest a functional association of a systemic signal with long-lasting IR in tomato. Additionally, investigations were conducted on the ability of strawberry seedlings (Fragaria x ananassa) to be chemically primed against B. cinerea, with large phenotypic differences seen in strawberry compared to tomato. This PhD therefore addresses current knowledge gaps on the long-lasting nature of priming including its maintenance and transmission. Elicitor screenings have investigated the influence of developmental stage on the plant’s imprinting capacity and stress memory formation. Through use of integrated omics approaches, (epi)genetic markers of long-lasting priming in tomato have been identified which may also serve as targets for durable resistance in other crops.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):