小麦TaSTK蛋白激酶介导的感条锈病机理

Wheat stripe rust caused by Puccinia striiformis f. sp tritici (Pst) is one of the most severe devastating diseases on wheat, which causes serious damage. Planting resistant cultivars is the most effective and friendly way to control this disease. However, the rapid virulence variation of Pst leads to a loss of resistance in currently resistant wheat cultivars, which results in frequent disease epidemics. Therefore, research on the mechanism underlying wheat resistance to Pst is of great significance in developing novel strategy to control the disease. In the preliminary study, a wheat serine-thronine protein kinase TaSTK is responsible for the susceptibility of wheat to Pst by RNAi technology. Yeast two hybrid screening revealed that one secreted protein from Pst and 4 wheat defense related protein could be targeted by TaSTK. Thereby, in this study, we plan to further analyze the manner in which the Pst secreted protein target TaSTK to suppress host immunity, and demonstrate the modulation of TaSTK on the following host targets. The results will reveal the regulation mechanism underlying TaSTK on wheat susceptibility to Pst and clarify the modulation network of TaSTK. Furthermore, we aim to create new resistance materials by genome editing TaSTK, which will provide technical support for genetic improvement of wheat resistance to stripe rust, and lay foundations to develop new strategies for durable and efficient control of stripe rust disease.

条锈病是小麦生产上危害最重的真菌病害之一，合理利用抗病品种是防治小麦条锈病最为有效、经济、环保的措施。然而，小麦品种常因条锈菌的频繁变异而“丧失”抗性，失去利用价值。因而，深入开展小麦抗条锈病机理研究，对开发条锈病防控新策略具有重要意义。在前期研究中，通过RNAi技术鉴定获得了小麦感条锈病基因TaSTK蛋白激酶，酵母双杂交筛选获得了其5个潜在的互作靶标，其中1个为条锈菌分泌蛋白，4个为小麦抗病性相关基因。为此，本项目拟在前期基础上，解析条锈菌分泌蛋白是如何调控小麦TaSTK蛋白激酶抑制寄主的免疫反应，以及TaSTK蛋白激酶如何作用于寄主的抗病靶标基因，以期揭示TaSTK蛋白激酶介导的小麦感条锈病机理，明确TaSTK基因的调控网络，并利用基因编辑技术创制新型抗条锈病材料，为小麦抗条锈病的遗传改良提供资源和技术支撑，为开发新的病害防控策略提供借鉴。

条锈病是小麦生产上危害最重的真菌病害之一，合理利用抗病品种是防治小麦条锈病最为有效的措施。然而，小麦品种常因条锈菌的频繁变异而“丧失”抗性，失去利用价值。修饰寄主感病基因或抗病负调控因子能够赋予植物广谱持久抗性，成为作物抗病性改良的重要途径。为此，本项目围绕小麦抗条锈病负调控因子鉴定、功能及在抗病性中的利用开展研究，取得了重要进展。①鉴定到2个小麦抗条锈病负调控因子，分别为受体蛋白激酶TaSTK与转录因子TaWRKY19；TaSTK-RNAi植株对小麦条锈菌表现显著抗性，TaSTK-OE植株对条锈菌感病性增强；瞬时沉默TaWRKY19显著增强小麦抗病性，稳定过表达TaWRKY19则降低小麦抗病性；②鉴定到上游调控TaSTK的条锈菌分泌蛋白PgSpg1，阐明PgSpg1为条锈菌关键致病因子，通过增强TaSTK自我磷酸化促进TaSTK入核，增强感病性，证实TaSTK为被条锈菌效应蛋白利用的感病基因；在细胞核中，TaSTK与TaCBF1互作并磷酸化TaCBF1，推测通过影响其转录活性干扰小麦抗病性；③阐明TaWRKY19与NADPH 氧化酶TaNOX10启动子区W-BOX元件结合，抑制TaNOX10基因的转录，导致胞间ROS积累减少，负调控小麦对条锈菌抗性；④利用CRISPR-Cas9技术对TaSTK与TaWRKY19基因进行编辑，成功创制了TaSTK-KO、TaWRKY19-KO突变体植株，实现了对所有拷贝的编辑； TaSTK-KO与TaWRKY19-KO植株对条锈菌抗性显著提高，并且TaSTK-KO对田间流行菌系均呈高抗，同时还对叶锈菌呈抗病反应；进一步，通过两年的大田实验证明TaSTK-KO植株在田间条锈菌群体表现良好的抗病性，且不影响小麦产量与生长，具有很强的应用前景。研究首次鉴定到小麦对条锈菌的感病基因，系统揭示了TaSTK介导感病性的PsSpg1-TaSTK-TaCBF1作用通路，并成功利用感病基因与抗病负调控基因创制了具有广谱抗性的小麦材料，为利用基因编辑技术创制新型抗条锈病材料提供技术支撑，为小麦抗条锈病的遗传改良提供了有价值的抗性资源，为开发新的病害防控策略提供借鉴。在本项目资助下，在Plant Cell、Molecular Plant Pathology、 Frontiers in Microbiology 发表SCI论文3篇。