CaWRKY39在辣椒响应疫霉菌侵染中的功能分析

Functional Analysis of CaWRKY39 Under Phytophthora capsici Infection in Pepper

以辣椒自交系007EA为材料,克隆了1个WRKY转录因子基因CaWRKY39,其开放阅读框为984 bp,编码327个氨基酸,含有1个WRKY结构域和C2H2型的锌指结构。氨基酸序列比对和进化树分析发现CaWRKY39与茄子SmWRKY7、番茄SlWRKY4和马铃薯StWRKY7同源性较高。基因结构分析显示CaWRKY39含有3个外显子和2个内含子。CaWRKY39启动子中含有W-box,以及响应光信号、ABA、MeJA、SA和生长素的顺式作用元件。亚细胞定位结果显示,CaWRKY39定位于细胞核和细胞质。qRT-PCR结果显示CaWRKY39在辣椒叶片中表达量最高,其次是茎、根等组织;此外其表达量在疫霉菌侵染植株叶片后明显上升。进一步通过VIGS技术沉默CaWRKY39,发现TRV:CaWRKY39植株对疫病的抗性比TRV:00对照明显降低。这些结果表明CaWRKY39可能正调控辣椒对疫病的抗性。

A WRKY transcription factor gene CaWRKY39 was cloned from pepper(Capsicum annuum L.)inbred line 007EA.The open reading frame of CaWRKY39 was 984 bp,encoding a protein of 327 amino acids,which contained a WRKY domain and a C2H2 zinc finger structure.Amino acid sequence alignment and phylogenetic tree analysis showed that CaWRKY39 had the highest homology with SmWRKY7,SlWRKY4 and StWRKY7 and gene structure analysis showed that CaWRKY39 contained three exons and two introns.Promoter analysis showed that CaWRKY39 promoter included W-box,and cis-acting elements responsive to light,ABA,MeJA,SA and auxin.Subcellular localization results showed that CaWRKY39 was located in the nucleus and cytoplasm.qRT-PCR results showed that CaWRKY39 displayed the highest expression in leaf,followed by stem,root,and other tissues,and its expression level was significantly increased after plant leaves infected by Phytophthora capsici.The function of CaWRKY39 was further studied by VIGS technology.TRV:CaWRKY39-silenced pepper plants were much sensitive to P.capsici infection compared with the TRV:00 control plants.These results of this study showed that CaWRKY39 may be involved in the resistance of pepper to phytophthora blight.