丹参DHAR家族基因的鉴定及表达模式分析

运用生物信息学方法，从丹参（Salvia miltiorrhiza）基因组数据库中鉴定得到5个脱氢抗坏血酸还原酶（Dehydroascorbate reductase，DHAR）家族成员SmDHAR1 ~ SmDHAR5，分析了基因结构特征、编码蛋白的理化性质、亚细胞定位、高级结构、系统进化关系以及启动子顺式作用元件，并考察了其在不同组织及胁迫下的表达模式。结果表明，SmDHAR基因家族成员长度在724 ~ 3 296 bp之间，含有1 ~ 5个外显子不等，编码218 ~ 470个氨基酸；其编码蛋白多为亲水性蛋白，且多不含跨膜结构域。SmDHAR家族成员分布在叶绿体和胞质外。系统进化分析结果显示丹参SmDHAR基因分为2个亚类。上游启动子区域分析发现SmDHAR基因家族成员均含有与植物发育、激素及胁迫响应相关的顺式作用元件。表达模式分析结果显示，SmDHAR5在丹参根中显著高表达，而在其余组织中表达量较低；SmDHAR1、SmDHAR3与SmDHAR4在根、茎、叶中表达量较高，在花组织中表达最低；SmDHAR2表现为组成型高表达。SmDHAR在茉莉酸甲酯、酵母提取物、脱落酸、赤霉素、水杨酸等处理时也表现出不同的响应模式。本研究的结果为深入探索丹参DHAR基因家族在抵抗逆境过程中的功能提供了参考。

Identification and Expression Analysis of Dehydroascorbate Reductase （DHAR）Gene Family in Salvia miltiorrhiza

Dehydroascorbate reductase（DHAR）catalyzes the glutathione（GSH）-dependent reduction of dehydroascorbate and plays a direct role in regenerating ascorbic acid，an essential plant antioxidant vital for defense. Salvia miltiorrhiza is a common traditional medicinal herb in China with abundant pharmacological activity. However，little is known about the DHAR genes in resistance of S. miltiorrhiza. In this study，5 DHAR genes were identified based on S. miltiorrhiza genome database. The characteristics of them were analyzed by bioinformatics method，such as basic properties of encoded proteins，subcellular localization prediction，protein structures，phylogenetic relationships analysis and cis-acting elements in promoter regions. Then，the expression pattern analysis of DHARs in different tissues and phytohormone treatments were tested. The results showed that the sizes of SmDHARs were 724–3 296 bp in length with 1–5 exons，and encoded 218–470 amino acids. Most of their coding proteins are hydrophilic and lack of transmembrane domains. SmDHARs located chloroplast or secreted to outside of cell. SmDHARs were divided into two subgroups based on phylogenetic relationships. Promoter regions of SmDHARs contain many cis-acting elements related to plant development，hormones and stress response. Gene expression analysis results demonstrated that all SmDHARs had vary expression patterns in tissues and under hormone treatments. SmDHAR5 expressed significantly highly in roots，while lowly in other tissues. SmDHAR1，SmDHAR3 and SmDHAR4 genes were highly expressed in roots，stems and leaves，and that is the lowest in flower. SmDHAR2 was constitutively highly expressed. And SmDHARs also showed different response patterns when treated with methyl jasmonate，yeast extract，abscisic acid，gibberellin，and salicylic acid. This study provides a reference for deeply exploring the function of SmDHAR gene family in the process of resisting adversity，and provides ideas for the research of resistance breeding in S. miltiorrhiza.