Molecular Characterization of Erysiphe necator (powdery mildew) resistance loci from the grapevine cultivar `Regent´ and their signaling network

葡萄品种瑞金特在第15染色体的基因座Ren3上携带对白粉病的抗性。在该位点鉴定出4个候选基因。需要对这些基因的功能进行表征，以确定介导耐药性的基因。它们的转录本将被详细研究（确定RNA的起始和结束，剪接变异体）。编码蛋白将与GFP（绿色荧光蛋白）融合研究其在细胞中的定位。所有这些试验将对接种和未接种的葡萄植株进行比较。在第15染色体上发现了一个抗性位点Ren9。需要对其序列进行分析，以确定其中编码的基因。随后，这些候选基因也必须对其功能进行表征。目前已确定的候选抗性基因根据其分子结构编码受体感知白粉病释放的信号分子（效应器）。受体和效应器之间的相互作用介导超敏反应（感染部位周围的局部细胞死亡）作为防御反应。通过将一个葡萄品种与Regent进行比较的RNA-Seq综合实验，将研究触发植物各种防御途径的信号转导网络。本实验将提供实验接种白粉病孢子或模拟接种后不同时间点的大多数活性基因的信息。差异活性基因应该能够解决有关的信号通路。关键的调控基因将被确定。在标记辅助葡萄育种中，利用分子标记对选育者进行标记后，提高选育者的耐久抗性。

The grapevine cultivar Regent carries resistance to Powdery Mildew on chromosome 15 at locus Ren3. In this locus four candidate genes were identified. These need to be characterized for their function to determine the gene that mediates resistance. Their transcripts will be investigated in detail (determination of start and end of RNA, splice variants). Encoded proteins will be studied in fusion with GFP (green fluorescent protein) in regard to their localization in the cell. All these experiments will be performed in comparison of E. necator inoculated and non-inoculated resistant and susceptible grapevine plants. An additional resistance locus Ren9 was found on chromosome 15. Its sequence needs to be analyzed for the genes encoded there. Subsequently, also these candidate genes have to be characterized for their function. The candidate resistance genes identified so far code for receptors sensing signaling molecules (effectors) released by powdery mildew according to their molecular structure. The interaction between receptor and effector mediates a hypersensitive response (a localized cell death around the infection site) as defense response. The network of signal transduction that triggers various defense pathways of the plant will be studied by a comprehensive RNA-Seq experiment comparing a susceptible grapevine cultivar to Regent. This experiment will deliver information on the majority of genes active at different time points following experimental inoculation with spores of powdery mildew or mock inoculation. Differentially active genes should enable to resolve the signaling pathways concerned. Key regulatory genes will be identified. They should be applicable to improve the breeders selection for durable resistance after tagging them with molecular markers for use in marker-assisted grapevine breeding.