DNA 甲基转移酶基因的表达分析表明 GhDMT6 触发了棉花对干旱和盐胁迫的反应中的 C5-MTase

DNA methylation is an important epigenetic mode of genomic DNA modification that is an important part of maintaining epigenetic content and regulating gene expression. Cytosine-5 DNA methyltransferases (C5-MTase) are the key enzymes in the process of DNA methylation. From now, there has been no systematic analysis the C5-MTase found in cotton. In this study, the whole genome of cotton C5-MTase coding genes were identified and analyzed using a bioinformatics method based on information from the cotton genome. Thirty-three C5-MTases wereidentified, of which8 belonged to Gossypium raimondii (D genome), 9 belonged to G. arboreum L.(A genome), and 16 belonged to G. hirsutum L.(AD genome). Systematic evolutionary analysis divided the 33 genes into four subfamilies, including 4 MET homologous proteins, 18 CMT homologous proteins, 8 DRM homologous proteins and 3 DNMT2 homologous proteins. After the protein domain alignment of C5-MTases in cotton, there are 6 conserved motifs involved in methylation modification in the C-terminus of 33 proteins, indicating that C5-MTases have basic catalytic methylation function. The N-terminal difference divides proteins into four classes, of which DNMT2 lacks the N-terminal regulatory domain. The expression of C5-MTases in different parts of cotton were different under different stress treatments, indicating the functional diversity of cotton C5-MTase gene family. GhDMT6-silenced by VIGS cotton seedlings under different stress treatments showed significant phenotypic differences. Compared with wild type cotton seedlings, GhDMT6-silenced scotton seedlings showed significant stress resistance. Our results suggest that C5-MTases may be involved in response to abiotic stress in cotton, which lays a foundation for further study on the mechanism of C5-MTases regulating cell cycle under abiotic stress.