Methylation analysis of Vedrantais and its CRISPR mutant at different stages of fruit ripening. Methylation analysis and fruit ripening in melon

Our methylome analysis of the climacteric variety VED showed an overall demethylation in CG and CHG context along fruit ripening. Single cytosine methylome analyses of the CmROS1 knockout mutant revealed DNA methylation changes in the promoter regions of key ripening genes as ACS1, ETR1 and ACO1, and ripening associated-transcription factors as NAC-NOR, RIN and CNR, suggesting the importance of CmROS1-mediated DNA demethylation for triggering fruit ripening in melon. To further investigate the targets of ROS1 we focused on the hypermethylated DMRs in the CRISPR-ROS1 line. Moreover, in CHH context at H time there are changes in the number of DMRs annotation between VED and the edited line. Among the CHH hypermethylated regions in CRISPR-ROS1 compared to VED at H time, 14% are associated with TEs, 46% with intergenic regions, 6% in promoter regions (defined as 1 kb upstream transcriptional start sites), and 33% in genic regions