WRKY转录因子在烟草受CMV侵染和激素处理中的表达模式初步分析

Expression patterns of WRKY transcription factor genes in tobacco plants upon CMV infection and phytohormone treatment

WRKY转录因子在调控植物抵抗病原菌的侵染中发挥重要作用,但是,目前为止还没有WRKY转录因子在烟草抗CMV中调控机理的研究。本研究检测了感病品种‘K326’和抗病品种‘TT8’在接种CMV后其WRKY1、WRKY2、WRKY4和WRKY11的表达情况。结果显示,CMV侵染后‘TT8’中4个WRKY转录因子表达量均有大幅上升;而‘K326’中WRKY2、WRKY4和WRKY11的表达量与CMV侵染前无显著差异,WRKY1表达量则大幅下降。幼苗经外源激素(水杨酸、茉莉素、乙烯)处理后用RT-PCR检测,结果表明,‘K326’和‘TT8’中WRKY转录因子对外源激素的诱导响应比较复杂多样,但总体表现为在‘TT8’中WRKY1、WRKY2和WRKY4会受到乙烯和茉莉酸的诱导,但在‘K326’中转录因子的表达未受明显诱导。

WRKY transcription factors play an important role in the regulation of plant resistance to pathogens.However,there is no report on the mechanism of WRKY transcription factors regulating the resistance of tobacco CMV（Cucumber mosaic virus）.In the present study,the expression patterns of WRKY transcription factor genes WRKY11,WRKY2,WRKY4 and WRKY1 were analyzed between tobacco varieties ’K326’（a CMV susceptible variety）and TT8（a CMV resistant variety）.The results showed that the expression levels of WRKY genes were significantly increased in ’TT8’ after CMV infection,while their expression in ’K326’ was tremendously different.The expression of WRKY2,WRKY4 and WRKY11 were not induced and that of WRKY1 was strikingly decreased in ’K326’.The transcription patterns of these WRKY transcription factor genes were consistent with the CVM resistance of ’TT8’ and ’K326’,as ’TT8’ and ’K326’ are resistant and susceptible to CMV,respectively.Exogenous application of phytohormone salicylic acid,jasmonate and ethylene resulted in a complicated transcription pattern of WRKY transcription factor genes in tobacco varieties ’K326’ and ’TT8’.Meanwhile,the observations suggested that the overall expression levels of WRKY1,WRKY2 and WRKY4 in ’TT8’ were induced byphytohormone salicylic acid,jasmonate and ethylene in ’TT8’,but no obvious induction was observed in ’K326’.The results of this study are valuable for revealing the roles of WRKY transcription factors in regulating tobacco resistance to CMV,and are helpful for investigating the molecular basis of CVM resistance between the tobacco varieties ’K326’ and ’TT8’.