拟南芥Hsp20基因家族的特征及其在干旱和盐胁迫下的表达分析

Characterization of Arabidopsis thaliana Hsp20 Gene Family and Its Expression Analysis Under Drought and Salt Stress

摘要

热激蛋白20 (heat shock protein 20, Hsp20)是植物响应非生物胁迫时广泛合成的一类功能蛋白质, 参与植物的抗逆过程。借助拟南芥基因组数据库, 利用生物信息学方法分析Hsp20基因家族。HMMER搜索和蛋白质的理化性质分析表明, 拟南芥至少含有30个Hsp20基因, 其编码蛋白的分子质量为14.6~41.4 kD, 且均含有α-晶状体蛋白结构域。系统发育分析表明, 在30个拟南芥Hsp20成员中, 22个归属于12个不同的亚家族, 其余8个归于未知分类, 可能为Hsp20类蛋白质(Hsp20-like)。共线性分析表明, 片段复制与串联复制是Hsp20成员的主要扩增事件, 大部分Hsp20不含或只含1个内含子。MEME分析结果表明, 基序1、2、9是Hsp20共有的保守基序。转录组分析提示, 15个Hsp20的表达水平在干旱和(或)盐胁迫后出现了上调, 该结果得到了qRT-PCR实验的验证。以上结果为人们进一步探究Hsp20基因的生物学功能提供了理论依据。

Abstract

Heat shock protein 20 (Hsp20) family contains a kind of functional proteins that are widely syn-thesized in plants in response to abiotic stresses. Herein, the Hsp20 gene family was analyzed by bioinfor-matics using Arabidopsis thaliana genome database. HMMER search and protein physicochemical property analysis showed that there are at least 30 Hsp20 genes in A. thaliana, encoding 14.6~41.4 kD molecular weight proteins, all of which contain an α-crystallin domain (ACD). Phylogenetic analysis showed that 22 of the 30 A. thaliana Hsp20 members belong to 12 different subfamilies, and the remaining 8 belong to un-known taxa, which may be Hsp20-like proteins. Collinearity analysis showed that fragment replication and tandem replication are the main amplification events of Hsp20 members, and most Hsp20 members contain no or only one intron. Analysis using MEME showed that motifs 1, 2, and 9 are common conserved motifs in Hsp20 family. Transcriptome analysis indicated that the expression levels of 15 Hsp20 genes were up-regu-lated after drought and (or) salt stress, which was verified by qRT-PCR assay. These results provide theoreti-cal basis for further investigation of the biological functions of Hsp20 genes.

关键词

拟南芥 / 热激蛋白20 (Hsp20) / 基因家族 / 生物信息学分析 / 非生物胁迫 / 表达分析

Key words

Arabidopsis thaliana / heat shock protein 20 (Hsp20) / gene family / bioinformatics analysis / abiotic stress / expression analysis