甘薯抗基腐病的遗传解析和抗性等位变异发掘

Sweet potato (Ipomoea batatas L.) is one of the major food crops in China. Foot Rot of sweet potato is a new fungal disease occurring in mainland China, which shows an increasing incidence year by year. It has become one of the important diseases causing severe yield loss of sweet potato in the southeastern coastal areas, and poses a risk to the occurrence in inland areas. However, the genetic law of resistance to foot rot in sweet potato is still unclear, and there is no report on mining of resistance-related genes. Several resistant cultivars were screened by our team from 300 sweet potato cultivars. In this study, we developed a F1 population derived from a cross between a resistant and a susceptible cultivar, and investigated the phenotypic performances of resistance-related traits to reveal the genetic law of resistance to root rot of sweet potato. Bulked segregation analysis (BSA) and specific-locus amplified fragment sequencing (SLAF-seq) were combined to analyze the association between resistance-related traits and allelic variation, and SNP loci which closely linked to resistance genes were identified. Specific molecular markers were developed and validated in a natural population, and molecular markers closely linked to the resistance genes were finally determined. This study will facilitate the use of resistance loci from resistant varieties and provide theoretical basis for the utilization of marker-assisted selection in sweet potato breeding.

甘薯是我国主要的粮食作物之一。甘薯基腐病(Foot Rot)是在我国大陆新发生的一种真菌性病害，呈现出危害逐年加重的趋势，在东南沿海地区已成为影响甘薯产量的重要病害之一，存在向内陆扩散的风险。但迄今为止，甘薯抗基腐病遗传规律尚不清楚，相关抗性基因资源挖掘未见报道。申请人所在团队已从300份甘薯资源中筛选出抗源品种。本项目拟以抗、感品种构建的F1分离群体为材料，通过评价抗病相关性状揭示甘薯基腐病抗性遗传规律。利用群体分离分析法(BSA)和简化基因组测序技术(SLAF-seq)相结合的方法，对甘薯基腐病抗性与等位变异进行关联分析, 获得与抗性基因紧密连锁的SNP位点。利用开发的特异分子标记，结合自然群体验证，最终获得与抗基腐病基因紧密连锁的分子标记，为抗性品种的抗基腐病位点的有效利用和分子标记辅助选择奠定基础。

由间座壳属病原菌（Diaporthe destruens）侵染引起的甘薯基腐病是浙江等东南沿海地区甘薯生产威胁最大的毁灭性病害。种植抗性品种是防治该病最为经济、环保和有效的措施。因此，解析甘薯基腐病抗性遗传规律和等位变异发掘具有较高的实用价值和现实意义。项目组利用前期鉴定的基腐病抗性材料构建F1分离群体，研究了不同抗源的杂种后代的抗性遗传规律，其抗性遗传有明显数量遗传特点，抗性基因具有累加效应，后代亦有超亲分离。通过构建2个极端性状的混合池用于全基因组重测序，鉴定出关联区域主要集中在4号染色体: 14,432,201~14,697,056bp区间（总长为0.26Mb），5号染色体:15,206,079~15,326,365区间（总长为0.12Mb），8号染色体：6,923,941~7,035,684）区间（总长为0.11Mb）。