甘薯IbWRKY75的克隆、亚细胞定位及表达特性分析

Cloning, subcellular localization and expression analysis of IbWRKY75 in Ipomoea batatas

本研究从甘薯‘徐薯18号’叶片中克隆获得一个IbWRKY75基因,其开放阅读框(ORF)为597 bp,编码198个氨基酸,含有一个WRKY结构域,锌指结构为C2H2型,属于WRKY转录因子家族。其编码蛋白为碱性不稳定疏水性蛋白,无信号肽,无跨膜结构域,包含37个磷酸化位点。系统进化分析表明该蛋白属于第Ⅱc类WRKY家族成员,与牵牛花InWRKY75亲缘关系最近。亚细胞定位结果显示该基因在细胞核中表达。qRT-PCR结果表明,正常生长条件下,IbWRKY75在甘薯不同组织中的表达量依次为茎>叶>根>叶柄;PEG和NaCl处理后,IbWRKY75在各组织中均上调表达,在根中的上调幅度最显著,推测该基因参与甘薯的抗旱、耐盐过程。另外,随着叶片的自然衰老,IbWRKY75的表达量逐渐增加,推测该基因可能正调控甘薯叶片的衰老。

In this study,the IbWRKY75 gene was cloned from the leaves of Ipomoea batatas cv.‘Xushu-18’.The open reading frame(ORF)length of IbWRKY75 was 597 bp,encoded 198 amino acids.It was a WRKY transcription factor,containing WRKY domain and C2H2 zinc finger domain.The IbWRKY75 was an alkaline unstable hydrophobic protein,without signal peptide and transmembrane domain.Phylogenetic analysis showed that IbWRKY75 belonged to the classⅡc protein of WRKY transcription factor family and had high homology with InWRKY75 of Ipomoea nil.Subcellular localization results suggested that the protein located in the nucleus.The real-time quantitative PCR(qRT-PCR)results showed that IbWRKY75 had highest expression in stem,followed by leaf,root and petiole.The expression of IbWRKY75 was significantly increased after induction by PEG and NaCl treatments,the most significant up-regulation was in roots,indicating that IbWRKY75 might mediate drought resistance and salt tolerance pathways in sweet potato.In addition,the transcriptional level of IbWRKY75 was significantly up-regulated with the natural aging of leaves,indicating that IbWRKY75 might be positively regulating the aging of leaves in sweet potato.