SlYL1靶向叶绿体负向调控番茄灰霉病抗性的分子机理

Botrytis cinerea is a necrotrophic pathogen, which is the second serious fungal disease in the world except rice blast. We located and cloned a susceptible candidate gene to gray mold on tomato chromosome 6 using GWAS technology of forward genetics previously. We named it SlYL1, which was localizated in chloroplast and induced by gray mold infection, overexpression of SlYL1 gene in tomato, causing tomato more susceptible to gray mold, indicating that it is a negative regulatory factor. Plant chloroplasts are not only the main source of energy as a plant cell, but also it involves in the production of a variety of defense signaling molecules. Until now, the relationship between plant chloroplast and necrotrophic pathogens is poorly understood. In this project, the genes interacted with SlYL1 and the regulated signal network will be studied by the technologies of yeast one-hybrid, yeast two-hybrid, RNA-seq and so on. Our purpose is to understand the molecular mechanism of how SlYL1 regulate plant susceptibility to gray mold in tomato by using SlYL1 overexpression and knockout plants as materials from the phenotypic, physiological, biochemical and molecular levels. This study will extent the mechanism of necrotrophic pathogens infecting plants and also provide a novel way to improve plant resistance to gray mold disease by knockouting this target of gray mold.

灰霉菌是一种死体营养型病菌，它是全世界范围内除稻瘟病外，危害植物第二严重的真菌病害。前期我们通过正向遗传学，利用全基因组关联（GWAS）的方法，在番茄第六号染色体上定位到一个调控灰霉病感病的基因，我们将其命名为SlYL1。该基因定位在叶绿体中，受灰霉菌侵染诱导，在番茄中超量表达该基因，导致番茄更加感病，说明其是一个负向的调控因子。植物叶绿体不仅是合成细胞能量的主要场所，它还涉及到多种防御信号因子的产生。目前，植物叶绿体与死体营养型病菌侵染的关系知之甚少。本项目将利用酵母单杂交，酵母双杂交，RNA-seq等技术，解析SlYL1的互作基因与调控的信号网络。以SlYL1超量和敲除植株为材料，从表型，生理生化，分子水平揭示其如何通过叶绿体调控植物抗性反应的分子机理。该研究将拓展死体营养型病原菌侵染植物的机制，通过敲除这个靶点，也为植物抗灰霉病提供了一条新的途径。

灰霉菌是一种死体营养型病菌，它是全世界范围内除稻瘟病外，危害植物第二严重的真菌病害。前期我们通过正向遗传学，利用全基因组关联（GWAS）的方法，在番茄第六号染色体上定位到一个调控灰霉病感病的基因，我们将其命名为SlYL1。该基因定位在叶绿体中，受灰霉菌侵染诱导，在番茄中超量表达该基因，导致番茄更加感病，说明其是一个负向调控番茄灰霉病的因子。我们利用酵母双杂交筛库实验，筛选到与SlYL1互作的蛋白RBCS3B。随后利用双分子荧光互补实验（BiFC）、免疫共沉淀实验（Co-IP）和萤火虫荧光素酶互补图像技术（LCI）等方法对互作关系进行验证。进一步对分子机理研究发现SlYL1可以抑制RBCS3B蛋白的积累，超量表达SlYL1后会抑制RuBPCase的活性。在烟草中干涉RBCS3B后，烟草叶片变黄，对灰霉病更加敏感。并且SlYL1蛋白在体内可以多聚泛素化，这种泛素化修饰会影响蛋白的稳定性。植物叶绿体不仅是合成细胞能量的主要场所，它还涉及到多种防御信号因子的产生。目前，植物叶绿体与死体营养型病菌侵染的关系知之甚少。该研究解析了SlYL1通过叶绿体蛋白RBCS3B调控番茄对灰霉病抗性的信号网络，拓展了死体营养型病原菌侵染植物的机制，通过敲除这个靶点，也为植物抗灰霉病提供了一条新的途径。