DNA Methylation Is Crucial for 1-Methylcyclopropene Delaying Postharvest Ripening and Senescence of Tomato Fruit

Abstract

DNA methylation is an epigenetic modification process that can alter the functionality of a genome. It has been reported to be a key regulator of fruit ripening. In this study, the DNA methylation changes of CpG islands of ethylene signaling genes regulated by 1-methylcyclopropene (1-MCP) during ripening and senescence of tomato fruit were detected. The results showed that the 1-MCP treatment decreased the accumulation of lycopene, maintained the content of vitamin C, and delayed the ripening and senescence of tomato fruit. The quantitative real-time PCR and bisulfite sequencing analysis showed that 1-MCP treatment changed the expression and the DNA methylation level of CpG islands related to the ethylene signaling pathway genes, among which the DNA methylation change of LeEIN3 was the most significant. Compared with the control, 1-MCP treatment increased the DNA methylation level of the CpG island of the LeEIN3 gene, reduced the expression of LeEIN3 in tomato fruit, and was involved in 1-MCP delaying the postharvest senescence of tomato fruit. The results indicated that DNA methylation changes of ethylene signaling genes were involved in ethylene synthesis and signal transduction and played an important role in the regulation of 1-methylcyclopropene, delaying postharvest ripening and senescence of tomato fruit.