水稻Os-miR169y参与对核盘菌非寄主抗性的分子机制及油菜菌核病抗性改良

核盘菌引起的菌核病严重危害油菜生产。油菜抗菌核病育种因缺乏抗源陷入瓶颈，利用水稻的非寄主抗性是改良油菜的新思路。前期研究发现水稻Os-miR169y受核盘菌诱导表达，该miRNA可靶向核盘菌核糖体基因SsRPL19；拟南芥、烟草、油菜等寄主叶片涂抹Os-miR169y、拟南芥过表达Os-miR169y、烟草诱导沉默SsRPL19，均可显著减小菌斑面积。我们推测Os-miR169y通过靶向核盘菌SsRPL19抑制菌的核糖体功能，参与水稻对核盘菌的非寄主抗性。本项目拟通过基因工程手段，在水稻中敲除Os-miR169y、在核盘菌中过表达Os-miR169y和敲除SsRPL19，以及在油菜中过表达Os-miR169y和诱导沉默SsRPL19，明确Os-miR169y参与对核盘菌非寄主抗性的分子机制及其对油菜抗性改良的潜力。本项目将拓宽核盘菌抗源范围，对油菜菌核病抗性改良有重要理论和实践意义。

Rapeseed (Brassica napus) suffers heavily from attack by fungal pathogen Sclerotinia sclerotiorum. Due to the lack of resistant resource in B. napus and relative species, the breeding of sclerotinia-resistant rapeseed has been difficult and rather unsuccessful. It is a novel strategy to utilize non-host resistance of rice in the improvement of rapeseed. In our previous study, a rice miRNA, Os-miR169y, was induced by S. sclerotiorum and it was found to target to a S. sclerotiorum ribosome related gene SsRPL19. The in vitro experiments on Arabidopsis, tobacco and rapeseed, the overexpression of Os-miR169y in Arabidopsis, as well as the host induced gene silencing of SsRPL19 in tobacco, significantly reduced the lesion size on these host plants. Therefore, we hypothesize that Os-miR169y plays a role in the non-host resistance of rice to S. sclerotiorum via inhibiting the fungal ribosome gene SsRPL19. This project will confirm the role of Os-miR169y via knocking out of this miRNA from rice, and will further investigate the resistant mechanism of Os-miR169y via overexpressing Os-miR169y and knocking out SsRPL19 from the pathogen. In addition, the role of Os-miR169y in improving sclerotinia-resistance of rapeseed will be investigated via overexpressing Os-miR169y and silencing SsRPL19 in rapeseed. This project will effectively broaden the resistance resources against S. sclerotiorum, and will provide both theoretical and practical significance on improving sclerotinia resistance in rapeseed.