烟草JAZ1基因的克隆和功能分析

Cloning and function analysis of JAZ1 gene from Nicotiana tabacum

JAZ(Jasmonate ZIM-domain)蛋白作为E3泛素连接蛋白降解复合体SCFCOI1受体的靶蛋白,是茉莉酸信号转导途径的关键组分。为了明确JAZ基因在烟草中的功能和调控方式,通过同源克隆技术从烟草中克隆到1个JAZ1基因,并结合生物信息学和基因表达模式分析进一步预测其生物学功能。结果表明:NtJAZ1基因cDNA序列长720 bp,具有完整的开放阅读框,编码239个氨基酸。NtJAZ1蛋白含有TIFY和CCT-2(Jas结构域)两个保守结构域,其二级结构由α-螺旋、延伸链和无规则卷曲组成,其三级结构具有TIFY超家族蛋白的结构特征。进化分析表明,NtJAZ1和番茄SlJAZ1同属1个分支,亲缘关系较近。在被黑胫病侵染发病的烟草根部,NtJAZ1的表达量最高,其次是茎和叶,推测NtJAZ1的高表达抑制了JA响应基因的表达,从而引发烟草黑胫病。

JAZ(Jasmonate ZIM-domain) protein, as a target protein of E3 ubiquitin ligase degradation SCFCOI1 complex receptor, is a key component in jasmonic acid signal transduction pathway. To identify the function and regulation mechanism of JAZ gene in tobacco, NtJAZ1 was cloned by homologous cloning strategy, and NtJAZ1 function was analyzed by bioinformatics and gene expression patterns. The results showed that NtJAZ1 encoded 239 amino acids with the cDNA sequence of 720 bp. NtJAZ1 protein contained two conserved domains: TIFY and CCT-2(also known as Jas domain). The secondary structure of NtJAZ1 consisted ofα-helix, extended chain and random coil, and its tertiary structure had the structural characteristics of TIFY superfamily protein. Phylogenetic analysis indicated that NtJAZ1 and SlJAZ1 belonged to the same branch and had a close genetic relationship. The expression level of NtJAZ1 was the highest in root treated by Phytophthora parasitica var. nicotianae, followed by stem and leaf. It was speculated that the high expression of NtJAZ1 inhibited the expression of JA response genes, which resulted in the occurrence of tobacco black shank.