全基因组水平解析甘蓝型油菜硫苷与菌核病抗性的关系

Sclerotinia stem rot caused by Sclerotinia sclerotiorum is one of the most devastating diseases of rapeseed in China. It is know that glucosinolates from Cruciferaes and their degradation products are with antimicrobial effect against pathogens including S. slcerotiorum. Therefore, it is of great importance to identify the crucial glucosinolate-related gene that affect the Sclerotinia stem rot resistance in rapeseed. In our previous study, transcriptome sequencing was conducted in B. oleracea and B. napus before and after inoculation with S. sclerotiorum among the most resistant and the extreme susceptible accessions, and five glucosinolate-biosynthesis-related genes were induced by S. sclerotiorum in all accessions. In this project, we plan to investigate the variations of the five glucosinolate-biosynthesis-related genes by whole genome resequencing of a natural population that containing 500 rapeseed lines, and to identify the candidate gene and its optimal haplotype that contributes greatly to Sclerotinia stem rot resistance via candidate gene association study. Furthermore, the biological function of the candidate gene will be identified via over expression and RNAi, and functional markers will be developed for molecular breeding of rapeseed. This project may reveal the association between glucosinolate-related gene(s) and Sclerotinia stem rot resistance, and will benefit to the breeding practices on improving resistance of rapeseed against S. sclerotiorum.

由核盘菌引起的菌核病是危害我国油菜生产的主要病害之一。油菜等十字花科植物营养体的硫苷及其降解产物对核盘菌等病原微生物具有抗菌作用，因此研究影响菌核病抗性的硫苷基因对于油菜的抗菌核病育种具有重要意义。前期我们分别对甘蓝和油菜极端抗病和感病材料进行了接种核盘菌前后的转录组测序，发现5个硫苷合成相关基因在所有材料中均受核盘菌诱导上调表达。本项目将利用500份油菜自然群体的全基因组重测序数据，对上述5个硫苷合成相关基因进行变异位点的检测，再结合菌核病抗性数据进行候选基因关联分析，挖掘对抗性贡献最大的候选基因及最佳单体型，最后通过超量表达和RNA干扰等实验验证候选基因的功能，并开发功能标记。本项目可一定程度阐明部分硫苷基因与菌核病抗性的关系，对于油菜抗菌核病分子育种有重要的实际意义。

次级代谢产物硫苷在油菜的抗病虫方面起到重要作用，但目前油菜的种子硫苷含量较高，因此研究油菜种子的硫苷含量对抗病虫育种具有重要意义。前期我们对307份不同生态型（春性、冬性和半冬性）的油菜进行全基因组重测序，并对多年多点的种子硫苷含量进行全基因组关联分析，对其中的36份极端种子硫苷含量的材料进行转录组测序。结果显示，在三个生态型油菜中，检测到4个共同和4个特异的单体型块与种子硫苷含量显著相关。进一步的单体型分析、基因组变异分析和候选基因表达分析显示，三个生态型中，鉴定到5个共有的候选基因，在春性材料中，鉴定到3个特定的候选基因与种子硫苷含量显著相关。表达模型说明，候选基因的加性效应可以进一步的降低种子的硫苷含量，该研究对油菜种子低硫苷含量的研究具有重要的指导意义。