棉花抗黄萎病遗传位点发掘及抗病候选基因功能解析

Verticillium wilt is a devastating disease of cotton causing serious impact on yield and quality of fiber. Breeding cotton cultivars possessing genes resistant to Verticillium wilt is the preferable approach to minimize the damage. However, the genomic variations of Verticillium wilt resistance underlying a diverse germplasms as represented by a natural population are unclear. The distribution of elite allele from QTLs linked to resistance in the national population of G. hirsutum is still obscure. And the novel loci or genes associated with the disease resistance are extremely sparse. In addition, the accurate of phenotype identification corresponding to Verticillium wilt resistance should be improved too. To solve these problems, here, we will carry out a systematic study on Verticillium wilt resistance in a core collection (419 accessions) selected from more than 7300 cultivated upland cottons planted in the major global cotton-growing countries. The main contents include that accurate identification of disease resistance phenotype across two different growing environments, analyzing genomic variations as well as associations with Verticillium wilt resistance, investigating the potential novel loci and known QTL as well as their distributions in the core population, identifying important candidate associated genes and studying genes functions as well as molecular mechanisms. This study should credibly provide new molecular markers and important function genes, which helped to deepen the understanding of the molecular mechanism of Verticillium wilt resistance and accelerate the progress of cotton disease resistance breeding.

黄萎病严重影响棉花产量和品质，利用抗病基因进行品种改良是控制该病的根本途径。鉴于陆地棉群体抗黄萎病变异不明确、已有抗病QTL在自然群体中优异等位变异不清晰、新的抗病位点发掘不够、突破性抗病基因缺乏的问题以及黄萎病抗性鉴定精准性有待提高的现状，本研究拟对从国内外不同生态植棉区搜集的7300余份陆地棉资源中筛选出的419份核心种质的黄萎病抗性系统研究：多环境抗病表型精准鉴定，分析群体黄萎病抗性变异特点；结合抗病性鉴定结果，全基因组关联分析寻找抗病显著关联的SNP位点；分析已知抗病QTL在419份核心种质的等位变异及分布，发掘新的抗病位点及SNP标记；结合表达谱测序和已报道的QTL结果，挖掘重要候选基因；对候选基因进行基因功能验证和抗病机理解析。本研究将丰富棉花抗黄萎病遗传基础，增加抗病标记，提供抗病新基因，为棉花抗病分子机理研究及抗病分子育种奠定基础。

黄萎病是棉花生产的主要病害，鉴定陆地棉抗黄萎病遗传变异与关键抗病基因对培育抗病品种、保障棉花生产意义重大。本研究明确了401份棉花核心种质的黄萎病抗性变异，筛选出12份抗病材料；全基因组关联分析获得352个与抗黄萎病显著关联的SNPs，其主要位于Dt11和At10染色体区段；发现被关联的Dt11染色体区段（Dt11:61909252—Dt11:62256064），包含18个在不同环境、不同菌系重复鉴定出的优异等位变异和23个候选基因，表明该染色体区段在棉花黄萎病抗性中发挥主要作用；进一步探明了位于At10关联区段的非脂质转运蛋白GhnsLTPsA10通过调节苯丙烷代谢通路黄酮类与木质素生物合成代谢流分支的重定向，来协调植物抗病虫的分子机制；揭示了硬脂酰去饱和酶基因GhSSI2介导的不饱和脂肪酸调控棉花抗黄萎病的分子机制；构建了基于棉花LncRNA分子介导的lnc_015092-GhLOX3-JA抗病调控网络。上述研究探明了棉花抗黄萎病优异SNP位点及其集聚规律，深化了棉花抗黄萎病分子机制。