UC Davis

Tomato (Solanum lycopersicum L.) is one of the most popular vegetable crops, and rich in vitamins, antioxidants and fiber. Tomato fruit are highly perishable, and require proper postharvest handling techniques to extend shelf-life. However, postharvest practices may negatively affect fruit quality. Tomato is also a well-established model for studying fleshy fruit ripening. DNA methylation, a kind of epigenetic modification, is involved in initiating tomato fruit ripening, with demethylation occurring in many ripening-related genes as fruit ripen. DNA methylation is also responsive to chilling stress and may regulate gene expression due to changes in external environments. However, the relationship between changes in DNA methylation, and fruit quality due to postharvest handling is still unclear. A better understanding of fruit ripening mechanism with a focus on DNA methylation may help find novel solutions to reduce fruit quality loss due to postharvest.Therefore, this work aimed to uncover the connection between tomato fruit DNA methylation status and fruit quality changes relating with two types of common postharvest practice, i.e., early harvest and low-temperature storage, using approaches such as Methyl-sensitive amplification polymorphism (MSAP) for DNA methylation and assessing fruit quality biomarkers. The results illustrated that early harvest and low-temperature storage could induce global DNA methylation changes. Furthermore, the alteration in DNA methylation is associated with quality parameters shown by multivariate analysis. This finding is not a comprehensive assessment, but it advances the understanding for tomato fruit ripening under postharvest handlings. In the future, I propose to connect the DNA methylation dynamics, transcripts abundance of the genes with fruit physiological changes altered by postharvest via more elaborate methods, i.e., fruit transcriptomic analysis and whole genome bisulfite sequencing for fruit DNA methylation.