关键词: 铁十字秋海棠, 叶斑, DNA甲基化转移酶, 植物激素

Abstract: DNA methylation is one of the important epigenetic modifications involved in the regulation of plant genome stability, development and stress responses. DNA methylation transferase is the key enzyme of DNA methylation. In order to investigate the function of DNA methyltransferase in Begonia masoniana, bioinformatics analysis was used to identify the genes encoding DNA methyltransferase, which 5 genes were obtained from the genome of B. masoniana. According to their structural characteristics, they were divided into three categories: CMT, MET and DRM. The gene sequence length and intron number of members in different categories were significantly different, but the gene structure and conserved domains of members in the same category were highly conserved. These proteins are located in the nucleus, and their promoters contain a large number of cis-acting elements such as light response, MYB binding, and plant hormone response elements.  Analysis of hormone response patterns also showed that the gene expression of CMT3 was significantly decreased under GA, SA and NAA, and the gene expression of CMT2 was significantly decreased under MeJA and NAA, while MET and DRM significantly increased respectively gene expression under GA and ABA. In addition, tissue specific analysis showed that the expression levels of BmaCMT2-5 and BmaDRM2-2 in leaves were significantly higher than those of other tissues, while the expressions of these two enzymes and BmaMET1-15 in red part of leaves were significantly higher than that of green part, implying that these three DNA methyltransferases may be involved in regulating the formation of leaf variegation.