SmEDS1调控茄子抗青枯病机理

EDS1(Enhanced Disease Susceptibility 1) played a key role in plant biotic and abiotic stress resistance. The eggplant SmEDS1 played positive regulation in bacterial wilt resistance which was identified by VIGS method. To reveal the mechanism of SmEDS1 regulation bacterial wilt resistance, the SmEDS1 was silenced by RNAi in resistance eggplant and over-expressed in susceptible eggplant. Main research content as followed: 1 After inoculation with R. solanacearum, the reactive oxygen species, activities of defense enzyme and endogenous SA content were analyzed to investigate the effected of SmEDS1 on the physiology and Biochemistry; 2 The expresion level of SA, ET and MAPK signal genes which involved in defense response also were analyzed;3 After inoculation with R. solanacearum 48 h，the RNA of root was extracted to construct homogenization yeast two-hybrid library.Using the SmEDS1 as bait, the unknown proteins which interacted with SmEDS1 were screened by yeast-2-hybrid system. Based on the above research，the SmEDS1 function and the mechanism of resistance to bacterial wilt were identified.

EDS1(Enhanced Disease Susceptibility 1)正调控植物防御生物和非生物胁迫反应。在本项目的前期研究中，通过VIGS技术证明SmEDS1正调控茄子抗青枯病的反应。在此基础上，利用RNAi（抗青枯病材料)和超表达（感青枯病材料）实验获得SmEDS1转基因植株，探究SmEDS1正调控茄子抗青枯病机理，具体内容如下：1 接种R. solanacearum后分析活性氧、防御酶活性及内源SA含量，探究SmEDS1对茄子生理生化的影响；2 分析SmEDS1对水杨酸、乙烯和MAPK级联信号途径中基因表达量的变化；3 在茄子抗青枯病材料接种后48 h提取RNA，构建茄子根部酵母双杂均一化cDNA文库，利用SmEDS1为诱饵蛋白，筛选抗病茄子材料中与SmEDS1互作的蛋白。通过上述研究进一步明确SmEDS1调控茄子抗青枯病的功能和其抗病机理。

青枯病是危害茄子产业的主要病害之一，而抗病品种的选育是防控青枯病最有效的手段。但是青枯病病原菌进化快，选育抗病品种的垂直抗性易丧失，因此研究抗病反应中的关键调节因子对于开展茄子的持久抗病育种，提高水平抗性有重要意义。EDS1(Enhanced Disease Susceptibility 1)在植物的抗病反应过程中发挥着重要的作用，我们的前期研究表明茄子的SmEDS1基因可能参与了正调控茄子青枯病抗性，但是其功能和机理尚不清晰。本研究通过遗传学手段证明茄子SmEDS1在正调控茄子的青枯病抗病反应。SA 水杨酸含量在超表达植株中显著上升。SmEDS1沉默后MAPK6、RAR1的表达量上调，而MAPK3、SIPK、PAD4、SGT1、TGA、EDR1、NPR1、ICS1、GLUA、EIL1和HSP90等基因的表达量下调，EBF2和ACO5的表达量不受SmEDS1的调控。为进一步研究其抗病机理，我们构建了一个感染青枯病病原菌R.solanacearum的茄子酵母双杂交文库，并且以pGBK7-SmEDS1为诱饵蛋白对酵母双杂交文库进行筛选，通过两次独立的筛选实验获得了TCP转录因子、DNAJ分子伴侣、SnRK1蛋白α亚基、氰酸酯酶、CIP4蛋白和1个未知蛋白等6个互作蛋白。基于这些蛋白的功能,推测SmEDS1可能通过与本研究筛选到TCP转录因子互作调控水杨酸的合成,进而调控茄子的青枯病抗性。通过Pull-down和BiFC研究结果表明SmEDS1与TCP7蛋白在体外和 体内均发生互作。本研究解析了SmEDS调控茄子抗青枯病机理，为选育持久抗性的抗青枯病品种奠定了良好的基础。