条锈菌效应蛋白Pst_Avr1c特异介导Yr1抗性的作用机理

条锈菌无毒基因（Avr）被小麦抗病基因（R）识别产生的抗性是小麦抗条锈病的重要形式。因此，小麦条锈菌Avr基因的克隆及其与对应R基因的互作机制研究将有助于深入揭示条锈菌与小麦的互作机制，加快对条锈菌毒性变异机理的认识。前期，通过在小麦中瞬时表达效应蛋白，获得1个能够在小麦Yr1近等基因系（Yr1NIL）中特异诱导过敏性坏死反应的效应蛋白Pst_Avr1c。为此，本项目拟进一步通过在Yr1 NIL中瞬时表达或在Yr1 NIL与无毒性条锈菌非亲和互作中沉默Pst_Avr1c，明确其无毒性；创制无毒性菌系的自交群体，分析自交后代无毒性与Pst_Avr1c的连锁，解析Pst_Avr1c对Yr1的特异识别；鉴定Pst_Avr1c在Yr1 NIL中的互作靶标，解析互作基因的功能，阐明Pst_Avr1c特异介导的Yr1抗性作用机制。研究结果对揭示小麦与条锈菌“基因对基因”的抗病机理具有重要意义。

Resistance to Puccinia striiformis (Pst) is significantly characterized by a cell death-associated defense response known as the hypersensitive response (HR), which is activated by the recognition of Pst avirulence genes (Avr) and the corresponding wheat resistance genes (R). Pst Avr gene cloning and deciphering the Avr- R interaction mechanism is of great significance in understanding the rapid virulence variation mechanism of Pst, which will further reveal the molecular basis of wheat –Pst interaction. However, due to the genetic complexity and unavailable genetic transformation system for the biotrophic Pst, no avirulence gene has been identified yet. In the preliminary study, through delivery of Pst effectors into wheat cells via bacterial type three secretion system (TTSS), one effector Pst_Avr1c was identified to specifically trigger HR on wheat Yr1 near isogenic line (NIL), exhibiting potential avirulence activity. Therefore, in this research, we plan to further analyze the avirulence role of Pst_Avr1c on Yr1 through transient expression in Yr1 NIL by Agrobacterium meditated infiltration, and knockdown of Pst_Avr1c in the incompatible interaction between Yr1 NIL-and avirulent Pst by host induced gene silencing (HIGS). Meanwhile, analyze the avirulence and Pst_Avr1c SNP marker segregation in a Pst population produced by selfing on a barberry plant to determine the linkage relationship of Pst_Avr1c for avirulence. Furthermore, identify its targets in Yr1 NIL and analyze the function of the targets. The results will reveal the mechanism of Pst_Avr1c in mediating Yr1-specific resistance, and provide in-depth knowledge on the “gene-for-gene” resistance of wheat to stripe rust.