辣椒DNA甲基化修饰酶基因的鉴定与表达特征分析

Identification and Expression Analysis of the DNA Methyltransferase and Demethylase Gene Families in Capsicum annuum L.

DNA甲基化与去甲基化是表观遗传修饰中一种保守的分子机制,参与植物生长发育、次生代谢和逆境胁迫响应等多种生物过程,受DNA甲基化修饰酶基因的调控。为了解DNA甲基化修饰酶基因在辣椒基因组中的特征,利用生物信息学手段鉴定出14个辣椒DNA甲基转移酶和去甲基化酶基因,并对其进行系统分析。结果表明:辣椒基因组中含10个DNA甲基转移酶和4个去甲基化酶基因,这些基因编码的氨基酸介于294~2037 aa之间,不均匀分布于除6号和11号染色体外的其余10条染色体上,基因所含的外显子数目在1~21之间,关系较近的基因拥有的保守域基本一致。组织特异性表达结果显示,CaCMT1和CaMET1-like在所有组织的表达量均很低,而CaDRM1-like2和CaROS1-like2在所有组织中表达量均较高。通过qPCR分析基因在高温和盐胁迫下的表达模式,对比高温处理的整个时期,发现处理3 h的材料中甲基化修饰酶基因表达量变化最明显,上调最高的基因分别为CaROS1-like2和CaROS1-like1;盐胁迫诱导下的材料在12 h处理时甲基化修饰酶基因最敏感,有9个基因表达量达到峰值,上调最高的基因分别为CaROS1-like2和CaDRM1-like1。本研究为进一步揭示辣椒DNA甲基化修饰酶基因家族在表观遗传学中的调控作用提供理论参考。

DNA methylation or demethylation is a highly conserved epigenetic modification involved in the regulation of numerous biological processes,including plant growth and development,secondary metabolism,and response to abiotic stresses,which controlled by DNA methyltransferase and demethylase genes.To fully understand the characteristics of DNA methylation modifying enzyme genes in the pepper genome,a total of 10 putative DNA methyltransferase and 4 demethylase genes were identified in pepper in the present study by using bioinformatics methods.The amino acids encoded by the genes were between 294–2037 AA.The genes were located on 10 different chromosomes,the number of exons contained in the 14 genes is between 1 and 21.The conserved motif compositions and exon-intron structures were systematically analyzed,and the results strongly supported the classification.Transcriptome data analysis proved that the expression levels of family member genes in different organs of pepper and different stages of fruit development were different.Among them,CaCMT1 and CaMET1-like showed the lowest expression in all organs,while CaDRM1-like2 and CaROS1-like2 showed the highest.The expression pattern of genes under high temperature and salt stress was analyzed by qPCR.Compared with the whole period of high temperature treatment,it was found that the expression of methylation modifying enzyme gene changed most obviously in materials treated for 3 hours,and the genes with the highest up-regulation were CaROS1-like2 and CaROS1-like1,respectively.The methylation modifying enzyme gene of the materials induced by salt stress was the most sensitive when treated for 12 hours,and the expression of 9 genes reached the peak,and the genes with the highest up-regulation were CaROS1-like2 and CaDRM1-like1.This study would provide a theoretical reference for further revealing the regulatory role of pepper DNA methylation modifying enzyme gene family in epigenetics.