条斑病菌调控水稻维生素B6合成机制的研究

利用植物抗病性是最经济有效的病害防治方式。前期围绕在水稻种质中缺乏抗条斑病基因这一科学问题开展研究，从病原致病性入手鉴定到一个条斑病菌关键性效应因子AvrRxo1，其抑制水稻抗病基因介导的抗性和烟草非寄主抗性，在烟草和酵母中表达产生毒性并在条斑病菌致病力中起重要作用。通过酵母双杂交、双分子荧光互补和免疫共沉淀等手段筛选并验证了一个与AvrRxo1互作的水稻蛋白OsPDX1.2，功能预测其参与维生素B6的合成。本项目将深入研究AvrRxo1对OsPDX1蛋白及其复合体功能的影响，阐明AvrRxo1介导的水稻条斑病菌致病分子机制，以及OsPDX1和维生素B6在植物抗病反应中的作用及其机制。该研究有望首次揭示细菌通过效应因子与寄主的PDX1蛋白复合体互作负调控维生素B6水平，而对植物产生毒性和抑制植物的抗性；植物则可以通过上调维生素B6水平，从而激发植物抗病反应的相互作用机制。

The utilization of plant disease resistance is the most economical and effective method of disease control. In preliminary work, the research on why it was difficult to identify the gene resistant to rice bacterial streak disease in rice germplasm was studied; a key effector AvrRxo1 of Xanthomonas oryzae pv. oryzicola was identified, which could inhibit the Xa21-mediated resistance in rice and the non-host resistance in tobacco; AvrRxo1 is toxic to both yeast and tobacco and influences bacterial pathogenicity. By yeast two-hybrid screen, BiFC and CoIP, we identified and confirmed an AvrRxo1-interacting proteins in rice, was named OsPDX1.2, which is a PDX1 homologue, involved in vitamin B6 synthesis. The aims of this project: 1.to explore the effects of this interaction on the function of OsPDX1 and OsPDX1 complex; 2. to find out the pathogenic molecular mechanism of Xanthomonas oryzae pv. oryzicola mediated by AvrRxo1; 3.to clarify The role of OsPDX1 and vitamin B6 in plant disease resistance and its mechanism. The research will reveal that the bacteria negatively regulate the level of vitamin B6 through its effector interacting with the host PDX1 complex, leading to toxicity and inhibition of plant resistance responses, while plants up-regulate the level of vitamin B6, which activate disease resistance in plants.