Identification of grape H3K4 genes and their expression profiles during grape fruit ripening and postharvest ROS treatment.

Fruit development is modified by different types of epigenetics. Histone methylation is an important way of epigenetic modification. Eight genes related to H3K4 methyltransferase, named VvH3K4s, were identified and isolated from the grape genome based on conserved domain analysis, which could be divided into 3 categories by the phylogenetic relationship. Transcriptome data showed that VvH3K4-5 was obviously up-regulated during fruit ripe, and its expression level was significantly different between 'Kyoho' and 'Fengzao'. The VvH3K4s promoters contains cis-acting elements of in response to stress, indicating that they may be involved in the metabolic pathways regulated by ROS signaling. The subcellular localization experiment and promoter activity analysis experiment on VvH3K4-5 showed that VvH3K4s may be regulated by H2O2. With H2O2 and Hypotaurine treatment, it was found that the expression pattern of most genes was opposite, and the expression level showed different expression trend with the extension of treatment time.