基于SLAF-seq技术的苦瓜白粉病SNP分子标记开发与抗性QTL定位

Bitter gourd (Momordica charantia L.) is a major vegetable in South-China, and bitter gourd production, which most of the product is distributed to the north and northeast part of China in cool season, is an important means for farmers to increase their income in China. Powdery mildew is a major disease which causes vastly economic losses in bitter gourd production; however, breeding programs for resistant varieties are dropped behind. In this project, identification of physiological races of powdery mildew on bittergourd in Guangxi, it could be Confirmed that what was disease races and of which race was the dominantone. Development of SNP Markers for powdery mildew-resistant in Bittergourd by by Specific Length Amplification Fragment Sequencing (SLAF-seq), and transformed into CAPS or D-CAPS marker ,which could be used to develop powdery mildew-resistant bitter gourd. meanwhile,High-density genetic map construction in bitter gourd based on SLAF-seq combined QTL mapping by tightly linked SNP markers were developed and finally the major QTL was fine mapped. In conclusion, clone the powdery mildew-resistant gene and provide techni-cal supports for molecular assisted breeding for dominantone race resistance in Bitter gourd. Therefore, this studyprovides high scientific significance and important application value.

苦瓜在瓜类蔬菜中经济效益较高且价格稳定，对农民增收与农业结构调整有着重要意义。而近年来，苦瓜白粉病发生极为严重，导致严重的经济损失。而我国苦瓜抗白粉病育种技术水平落后，可利用的抗病品种匮乏。本项目在收集到大量种质资源的基础上，开展苦瓜白粉病菌生理小种鉴定，明确中国苦瓜主产区的白粉病菌生理小种和优势生理小种。利用SLAF-seq深度测序技术，筛选出与白粉病抗病性状紧密关联的差异标记，并转化成CAPS或D-CAPS分子标记，对苦瓜育种材料进行分子标记辅助选择，提高抗病育种效率。同时，利用SLAF-seq 开发的SNP 标记构建高密度的遗传连锁图谱，结合抗病鉴定数据对白粉病菌优势生理小种抗性进行QTL 定位。为抗白粉病基因的精细定位和图位克隆，挖掘白粉病抗性候选基因奠定基础。因此，本项研究具有较高的科学意义和应用价值。

苦瓜是广西“南菜北运”的主要蔬菜种类，对农民增收与农业结构调整有着重要意义。目前，白粉病已成为苦瓜生产中最主要的病害，严重影响产量和品质。项目通过明确广西苦瓜主产区的白粉病菌生理小种和优势生理小种。通过高抗白粉病苦瓜（MC18）和高感白粉病苦瓜（MC105、MC402）构建遗传分离群体，利用SLAF-seq和全基因组重测序技术，筛选出与白粉病抗病性状紧密关联的差异标记，对苦瓜育种材料进行分子标记辅助选择。同时构建高密度的遗传连锁图谱，结合田间抗病鉴定对白粉病抗性进行QTL 定位,以及RNA-Seq测序对苦瓜白粉菌侵染过程进行转录调控研究。结果表明：广西苦瓜主产区的白粉病菌生理小种1危害最为严重，获得苦瓜白粉病抗病性状紧密关联的SNP标记5个，CAPS分子标记2个，显著提高抗病育种效率。初步将白粉病主效抗白粉病QTL定位于3号染色体，命名为Pm3.1，遗传距离14 cM，物理距离为2.9Mb，在候选区域开发InDel分子标记3个，获得2个差异表达基因进行功能验证（ID：MC03g_new0423；ID：MC03g0854）。本研究结果为抗白粉病基因的精细定位和图位克隆，挖掘白粉病抗性候选基因奠定了基础。