水分胁迫下小麦TaWSI18基因的电子克隆及生物信息学分析

Identification and characterization of water stress-induced TaWSI18 gene in silico cloning from Triticum aestivum and its bioinformatic analysis

利用电子克隆和RT-PCR技术,从干旱胁迫的小麦叶片中分离出4条新的具有高度同源性的WSI18基因,即TaWSI18-1、TaWSI18-2、TaWSI18-3和TaWSI18-4(Gene Bank登陆号分别为:KP226849、KP226850、KP226851和KP226852);其开放阅读框均为678 bp,编码225个氨基酸。生物信息学分析表明,该类蛋白具有亲水性,存在多个磷酸化位点,无信号肽结构域及剪切位点,定位于细胞质中,无跨膜结构域;二级结构分析表明,该蛋白α螺旋和无规则卷曲的比例达到90%以上;同源性比较及聚类分析表明,小麦TaWSI18蛋白同无芒雀麦(Bromus inermis,BAN15016)WSI18蛋白和二穗短柄草(Brachypodium distachyon,XP 003569641)LEA3蛋白具有高度的同源性,相似性分别为94%和70%。小麦TaWSI18基因编码蛋白的氨基酸序列的N端存在与LEA蛋白的N端区域高度保守的序列。表明小麦TaWSI18蛋白的性质与LEA3蛋白的相似,说明了小麦的TaWSI18蛋白可能与LEA3蛋白存在相同或相似的功能,为进一步研究其在小麦水分胁迫下的功能奠定基础。

WSI18,a water stress- induced genes,plays an important role in plants under water deficit. Silico cloning and RT- PCR were taken to isolate four new highly homologous WSI18 genes： TaWSI18- 1,TaWSI18- 2,TaWSI18- 3 and TaWSI18- 4（ Gen Bank accession number： KP226849,KP226850,KP226851 and KP226852）in wheat,ORFs of which are all 678 bp encoding 225 amino acids. Bioinformatic analysis showed that they are highly hydrophilic and have multiple phosphorylation sites. They are located to cytoplasm and have no transmembrane domain signal peptides,as well as no splicing sites. The proportion of α helix and random coil are over 90%by a secondary structure prediction. Homology comparison and phylogenetic analysis showed that TaWSI18 proteins are highly homologous to WSI18 of Bromus inermis and LEA3 Brachypodium distachyon,sharing 94% and 70%similarities respectively. In addition,TaWSI18 proteins have conserved amino acid sequences common to LEA protein in the N-terminal region. They also have a similar character to LEA3 protein by bioinformatic analysis that TaWSI18 proteins may have the same or similar function to LEA3 protein,which lies a foundation for the future study on its function under water-stress.