黄灯笼辣椒CcWRKY4基因克隆及表达分析

Cloning and Expression Analysis of CcWRKY4 Gene in Capsicum chinense

WRKY转录因子是植物中最大的转录因子家族之一,在植物生长发育、新陈代谢、生物和非生物胁迫等多种生物学过程中发挥着重要作用。本研究从海南黄灯笼椒(Capsicum chinense)中克隆了CcWRKY4基因,其开放阅读框长1461 bp,编码487个氨基酸,分子量为54.01 kD,理论等电点pI为6.77,为亲水性蛋白;无信号肽,预测其为非分泌蛋白。结构域分析显示该基因属于WRKY基因家族的I类。系统进化树分析表明CcWRKY4与烟草、番茄和马铃薯的同源蛋白亲缘关系最近,其次为AtWRKY3、AtWRKY4。进一步预测该基因启动子区域有水杨酸、脱落酸响应元件以及多个光响应元件。RT-qPCR分析表明,CcWRKY4基因在辣椒的胎座和果肉中均有表达,其表达趋势为花后10~20 d升高,至30 d达到峰值后表达量逐渐降低,与辣椒素合成的趋势相似。该研究结果为CcWRKY4在辣味中的调控功能提供了一定的科学依据。

WRKY transcription factor is one of the largest transcription factor family in plants,which play an important role in plant growth and development,metabolism,biotic and abiotic stress and other biological processes.CcWRKY4 gene was cloned from Capsicum chinense with 1461 bp open reading frame,487 amino acids,54.01 kD molecular weight,and p I 6.77.CcWRKY4 is a hydrophilic and non-secreted protein with no signal peptide predictly.Domain analysis showed that the gene belonged to class I of the WRKY gene family.Phylogenetic tree analysis showed that CcWRKY4 was closely related to homologous proteins of tobacco and potato,followed by AtWRKY3and AtWRKY4.Promoter analysis predicted that the promoter region of this gene had salicylic acid,abscisic acid response elements and multiple light response elements.RT-qPCR analysis showed that CcWRKY4 gene was expressed in placentas and pericarps of pepper,and its expression trend was increased 10~20 d after flowering,and gradually decreased after reaching the peak at 30 d,similar to the trend of capsaicin synthesis.The results of this study provide a certain scientific basis for the function of Cc WRKY4 gene.