番茄抗虫传病毒病害的关键调控因子的发掘和功能解析

Eighty percent of plant viruses are exclusively transmitted by insect vectors. Due to the lack of efficient resistance genes, the loss of resistance and host dependent mutualism, it has caused huge economic losses. Whitefly-transmitted geminivirus diseases are one of most important viral diseases in tomato (Solanum lycopersicum) in China. The research has revealed that geminivirus, which interacted with MYC2 transcription factor in host jasmonic acid (JA) pathway, inhibited the expression of genes which positively regulated by MYC2, resulting in geminivirus and whitefly shared host plant to establish an indirect mutualistic relationship. It also showed that geminivirus could attenuate the expression of genes which negatively regulated by MYC2 factor. This indicates that the mechanism of how plant JA pathway defenses against geminivirus is complex. With geminivirus effector as a probe, yeast two hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) will be employed to screen the interaction of viral protein and host protein. The new transcriptional regulator in JA pathway will be found out, and the defense mechanism of how JA pathway mediates resistance against vector-borne viral diseases will be further studied. Single plant mutants and multiple mutants crossing with myc2 mutant will be obtained by gene editing technique. The differences of resistance against viruses and vectors in various genetic materials will be tested. The molecular mechanism of how the new regulator of JA pathway blocks the interaction between geminivirus and whitefly, leading to improve host double defenses against viruses and vectors, will be analyzed. The researches on the new regulator of JA resistance pathway and its regulatory mechanism will help to provide theoretical reference for the new strategy of green plant protection.

近80%的植物病毒都是经介体昆虫来传播的，由于缺乏高效的抗病基因、抗性易丢失、病毒与介体昆虫互惠共生等特点，造成巨大的经济损失。烟粉虱传的双生病毒病是我国番茄生产中最重要病害之一，研究表明双生病毒与茉莉酸途径MYC2因子互作抑制其正调控的基因表达，同烟粉虱依赖寄主间接互惠共生。此外，MYC2负调控的基因也被双生病毒抑制，说明双生病毒干扰植物茉莉酸途径的作用机制是复杂的。因此本项目拟以病毒因子为探针，通过Y2H、BiFC等手段筛选寄主互作因子，发掘番茄茉莉酸途径中抗虫传病毒病害的关键调控因子，研究新的调控因子防御虫传病毒病害的分子机制。拟通过基因组编辑等手段获得植物单突变体和同myc2的多突变体，研究多种遗传学材料对病毒和介体昆虫抗性的差异，阐明茉莉酸途径新的调控节点阻断病毒-介体昆虫依赖寄主间接互惠共生，提高寄主对病毒和介体昆虫的双重防御能力的作用机制，为绿色植保新的策略提供理论参考。

近80%的植物病毒都是经介体昆虫来传播的，植物病毒与媒介昆虫依赖寄主植物的互惠共生现象，导致病害的流行往往伴随虫害的爆发，对农作物的生产带来了极大的威胁，由于缺乏高效的抗病基因、抗性易丢失等特点，造成巨大的经济损失。烟粉虱传的双生病毒病是我国番茄生产中最重要病害之一，我们课题组前期的研究表明双生病毒与茉莉酸途径关键调控因子MYC2互作抑制萜烯类化合物的合成，同烟粉虱依赖寄主间接互惠共生。因此本项目以烟粉虱传双生病毒为模式系统，以病毒编码的致病因子βC1为探针，通过酵母双杂交筛选与寄主互作的因子，发掘番茄茉莉酸途径中抗虫传病毒病害的关键调控因子，解析虫媒病毒的多元互作机制。我们最近的研究揭示了双生病毒通过调控宿主植物WRKY20介导的多种抗性途径，影响植物-媒介昆虫以及与非媒介昆虫等生态因子的互作关系，进一步促进了双生病毒与烟粉虱的互惠共生。我们还发现红光能够促进双生病毒对烟粉虱的吸引和病毒蛋白的累积，从而促进病毒和媒介的互惠共生，而远红光能够破坏病毒在植物体内的稳定性，降低病毒感染植物对烟粉虱的吸引作用，减少病毒的有效传播，为物理防治（如使用远红光的LED灯）植物虫媒病毒病害提供了很好的理论基础。通过对病毒-媒介昆虫-植物作用机制的解析，我们获得了防御植物虫媒病毒病害的新基因资源以及物理防控新策略。