黄瓜白粉病抗性主效基因Cspm5.2介导的抗性机制分析

白粉病是黄瓜种植过程中的主要病害之一，严重影响黄瓜的生产，培育抗病黄瓜新品种能有效解决这一问题。黄瓜白粉病抗性是多基因控制的数量性状，除Csmlo1基因外，还受其它基因的控制。克隆并分析新的抗性基因及其抗性机制对黄瓜白粉病抗病育种意义重大。本研究图位克隆了一个新的黄瓜白粉病抗性主效基因Cspm5.2，并通过遗传转化进行了功能互补验证。Cspm5.2在拟南芥和水稻中的同源基因均编码了一个跨膜的无机磷转运蛋白，参与了无机磷的转运。我们认为有两种可能：(1) Cspm5.2基因在黄瓜中通过无机磷的转运介导了黄瓜白粉病的抗性；(2) Cspm5.2基因在黄瓜中可能通过其它未解析的功能参与黄瓜白粉病抗性的形成。本研究将通过生化、细胞与分子生物学手段深入研究黄瓜Cspm5.2基因的功能、该基因对白粉病菌侵染过程的影响以及它参与的白粉病抗性的调控路径，最终揭示黄瓜Cspm5.2基因介导的白粉病抗病机制。

Powdery mildew (PM) is one of the main diseases in cucumber planting, which seriously affects cucumber production. Breeding new disease-resistant cucumber varieties can effectively solved this problem. PM resistance in cucumber is a quantitative trait controlled by multiple genes. Besides Csmlo1, some other genes also control PM resistance. Therefore, the cloning of new resistance genes and the analysis of their resistance mechanisms are of great significance to the breeding of cucumber varieties that resistant to powdery mildew. In this study, a new major gene, Cspm5.2, which control PM resistance in cucumber was cloned by map-based cloning and confirmed by transgenic functional complementation The homologous gene of Cspm5.2 in Arabidopsis and rice encodes an inorganic phosphorus transporter across membranes, which is involved in the transport of inorganic phosphorus. We think there are two possibilities: (1) PM resistance mediated by Cspm5.2 was through the transport of inorganic phosphorus in cucumber; (2) Cspm5.2 may be involved in the formation of PM resistance through other undetermined functions in cucumber. In our research, the function of Cspm5.2, the influence of Cspm5.2 on the infection process of powdery mildew and the regulatory pathway of PM resistance involved by Cspm5.2 were further studied by biochemical, cellular and molecular biological methods, and the mechanism of PM resistance mediated by Cspm5.2 was finally revealed.