黄瓜白粉病mlo抗性相关基因的挖掘与鉴定

Powdery mildew (PM) is one of the most serious diseases in cucumber production, and breeding of PM resistant cultivars is the most effective strategy to control this disease. Mining and identification of genes resistant to PM is therefore critical for development of resistant culivars using molecular breeding methods in cucumbr. However, breeding for resistant cucumber is greatly slowed down due to the little advance in the identification and cloning of resistant genes in cucumber. We have cloned and identified a major resistant gene, Csmlo1, in cucumber previouly. We found that the fucntion of Csmlo1 requries other genes to participate in. Based On this finding, we aim to identify genes required for the function of Csmlo1 in this study. By comparing the difference in the transcriptome and gene expression of the cucumber near-isogenic line with the major PM resistance loci before and after inoculation of PM, the specifically expressed genes related to mlo-mediated resistance will be identified. Meanwhile, the key genes requied for Csmlo1 resistance will be uncovered using genetics, molecular biology and bioinformatics. In addition, easy-testing markers would be developed for marker-assisted breeding of PM resistance in cucumber. The mining and identification of related genes required for the Csmlo1 resistance in this study will provide important theoretical basis for molecular breeding of PM resistance and accelerate the progress of breeding for PM resistance in cucumber.

白粉病是黄瓜生产最严重的病害之一，培育抗病黄瓜品种是解决其危害最有效的途径。白粉病抗性基因的寻找和鉴定对于黄瓜白粉病抗性分子育种具有重要意义。但目前关于黄瓜白粉病抗性基因的克隆和鉴定工作还很薄弱，不能满足抗性育种的需要。我们已经对黄瓜白粉病抗性主效基因进行了图位克隆和鉴定，但发现主效基因Csmlo1抗性的发挥需要其它基因协同参与。本项目拟在此基础上，对Csmlo1抗性所需的相关基因进行挖掘和鉴定。以构建的黄瓜白粉病抗性主效位点的近等基因系为材料，通过接种白粉菌前、后的转录组和差异表达分析，寻找白粉病mlo抗性特异表达基因，并通过遗传学、分子生物学和生物信息学等方法鉴定出黄瓜mlo抗性所需的关键基因，同时开发抗性基因相关的分子标记，可用于白粉病抗性育种的分子标记辅助选择。本研究对Csmlo1抗性相关基因的挖掘和鉴定，将为黄瓜白粉病抗性分子育种提供重要的理论依据，加快黄瓜白粉病抗性育种的进程。

白粉病是黄瓜生产中最严重的病害之一，培育抗病的黄瓜品种是解决其危害最有效的途径。白粉病抗性基因的寻找和鉴定对于黄瓜白粉病抗性分子育种具有重要意义。但目前关于黄瓜白粉病抗性基因的克隆和鉴定工作还很薄弱，不能满足抗性育种的需要。我们已经对黄瓜白粉病抗性主效基因进行了图位克隆和鉴定，但发现主效基因Csmlo1抗性的发挥需要其它基因协同发挥作用。本项目拟在此基础上，对Csmlo1抗性所需的相关基因进行挖掘和鉴定。以构建的黄瓜白粉病抗性主效位点的近等基因系为材料，通过接种白粉菌前、后的转录组和差异表达分析，寻找白粉病mlo抗性特异表达基因lncRNA与mRNA。我们共鉴定到12903 个lncRNAs 和 25598 mRNAs，其中差异表达分析得到119 lncRNAs 和 136 mRNAs是白粉病的抗性特异表达基因，响应了白粉病抗性。功能分析显示这些差异的lncRNA 与差异的mRNAs 同时与苯丙素的生物合成，苯丙氨酸代谢，泛醌与其它萜类化合物-醌的生物合成，内吞作用显著关联。特别的是，两个lncRNA LNC_006805 与LNC_012667 可能在白粉病抗性中起到很重要的作用。另外，我们预测了成熟的miRNA和可能参与白粉病抗性的竞争性ceRNA lncRNA–miRNA–mRNA网络。其中, 有49个差异表达lncRNAs可能作为106个miRNAs的靶标类似物。本研究对Csmlo1抗性相关遗传因子的挖掘和鉴定，将为黄瓜白粉病抗性分子育种提供重要的理论依据，加快黄瓜白粉病抗性育种的进程。