黄瓜/酸黄瓜渐渗系抗南方根结线虫的分子机制研究

The occurrence of southern root-knot nematode (RKN, Meloidogyne incognita) result in huge losses to cucumber (C. sativus L., 2n=14) production. As there is no resistance available in cucumber resources and varieties, it is of great significance to explore and utilize the RKN resistance genes for cucumber genetic improvement. In previous studies, an RKN-resistant introgression lines (ILs), which can be used directly in breed improvement, was created, derived from the successful hybrization between cucumber and the wild cucumber (Cucumis hystrix Chakr., 2n=24). However, the molecular mechanism of resistance in the Cucumis-hystrix IL. The applicant constructed a high-density genetic bin-map using an IL10-1. QTL mapping was conducted, as well as candidate resistant genes were predicted based on it. Combining with transcriptome sequencing analysis, the resistance mechanism was preliminary studied. In the current project, we will clone the candidate resistant genes to RKN in this Cucumis-hystrix introgression line IL10-1 based on the basis mentioned above. The functional verification and the temporal and spatial expression patterns analysis of candidate genes will be performed by in situ hybridization, subcellular localization combining genetic transformation and histopathological observation. Furthermore, omics joint analyzing based on iTRAQ and phosphorylated proteomic sequencing will be carried out to clarify the interactions among genes, proteins and phosphorylation sites. The gene regular network will be built, and the molecular resistance mechanism will be uncovered in this Cucumis-hystrix introgression line IL10-1. The proposed research will deal with the challenges of RKN resistance breeding in cucumber, which will also contribute the important molecular basis for the study of RKN resistance.

南方根结线虫(Meloidogyne incognita)的发生给黄瓜生产带来巨大损失。由于现有黄瓜种质资源和栽培品种中缺乏抗性，发掘和利用抗南方根结线虫基因对黄瓜遗传改良具有非常重要的意义。本研究前期通过黄瓜与野生酸黄瓜杂交创制了抗南方根结线虫的黄瓜/酸黄瓜渐渗系，可直接用于品种改良，但其抗性分子机制还不清楚。申请者利用黄瓜/酸黄瓜渐渗系IL10-1构建了bin-map高密度遗传图谱，进行了抗性QTL定位和候选基因预测，结合转录组测序，初步探讨了其抗性机理。本项目拟在此基础上克隆抗南方根结线虫候选基因，利用原位杂交、亚细胞定位、遗传转化等手段进行表达模式分析和功能验证；进一步通过组学联合分析，明确基因、蛋白和磷酸化位点的互作关系，构建抗性调控网络，探明IL10-1抗南方根结线虫的分子机制。研究结果能够突破黄瓜抗南方根结线虫遗传改良的瓶颈，为南方根结线虫抗性机制研究提供重要的分子理论基础。

南方根结线虫(Meloidogyne incognita)的发生给黄瓜生产带来巨大损失。由于现有黄瓜种质资源和栽培品种中缺乏抗性，发掘和利用抗南方根结线虫基因对黄瓜遗传改良具有非常重要的意义。本研究前期通过黄瓜与野生酸黄瓜杂交创制了抗南方根结线虫的黄瓜/酸黄瓜渐渗系，可直接用于品种改良，但其抗性分子机制还不清楚。本项目利用南方根结线虫抗性材料黄瓜-酸黄瓜渐渗系IL10-1与感病对照北京截头CC3构建的重组自交系群体为材料，通过多年多点的人工接种鉴定工作，构建了bin-map高密度遗传图谱，进行了黄瓜-酸黄瓜渐渗系中对南方根结线虫的抗性基因/QTLs定位，筛选获得了候选基因，并开展了部分基因功能验证工作；此外，结合转录组、蛋白组测序以及根系组织病理切片观察等综合分析，绘制了黄瓜-酸黄瓜渐渗系IL10-1对南方根结线虫的抗性基因调控模式图，初步解析了其抗性分子机制，本项目的研究成果为突破黄瓜抗南方根结线虫遗传改良的瓶颈和南方根结线虫抗性机制研究提供重要的分子理论基础。