Unveiling the Role of Cytosine-5 DNA Methyltransferase Under Heat Stress in Rose (Rosa chinensis)

DNA methylation is a well-recognized epigenetic modification linked to plant development, and it serves a crucial function in safeguarding the genome, governing gene expression, and enhancing stress resilience in plants. This mechanism is carried out by several conserved cytosine-5 DNA methyltransferases (C5-MTases). In the present study, a total of 10 C5-MTases were identified in rose. Our comprehensive examination, encompassing the study of conserved domains, gene structures, and phylogenetic analysis, led to the categorization of RcC5-MTases into four distinct subgroups: CMT, MET, DRM, and DNMT2. During the present study, numerous cis-elements that play roles in plant growth and development, phytohormone responsiveness, stress adaptation, and light sensitivity were also identified. A significant downregulation in the expression of RcC5-MTase genes (RcCMT1, RcCMT2, RcMET1, RcMET2, RcDRM1, and RcDRM3) were observed under HS, while the heat shock factor RcHsp17.8 was significantly upregulated, contributing to heat tolerance. RcCMT2 expression decreased by 9.8-fold at 6 h, 17.24-fold at 12 h, and 15.88-fold at 24 h under HS. Although RcDRM1 showed non-significant downregulation at 6 and 12 h, a significant decrease of 7.76-fold was observed at 24 h. RcDRM3 consistently showed significant downregulation at all time points, with the highest decrease of 21.79-fold observed at 24 h. Overall, the present investigation provides significant insights into the expression and function of rose C5-MTase-encoding genes. This information will be valuable for future experimental research on the processes of epigenetic control in rose.