水稻OsBDR2基因在稻瘟病抗性中的功能研究

Rice blast disease， the most destructive disease of rice globally, is caused by a filamentous ascomycetous fungus, Magnaporthe oryzae. This disease causes enormous reduction in the yield of rice. Upon pathogens attract, including infection of rice by Magnaporthe oryzae, rice has evolved a sophisticate innate immunity system, which are divided into two layers that is Pathogen-associated molecular pattern-triggered immunity (PTI) and Effectors-triggered immunity (ETI). Recent studies have identified a number of PAMPs and effectors from the blast fungus that trigger rice immune response upon perception. However, more challenges and opportunities in further investigation are coming. We found a new PTI-related gene OsBDR2 which was up regulated in blast infected plants. Otherwise, silencing of OsBDR2 by RNA interference (RNAi) enhanced rice resistance to Magnaporthe oryzae. Here, we will combine genetics, ecology and molecular biology to investigate the molecular mechanism of OsBDR2 in order to promote further study on their interaction and provide reference for rice breeding for blast disease resistance.

稻瘟病是由稻瘟病菌Magnaporthe oryzae引起世界性水稻重要病害，给水稻生产带来了非常严重的损失。在抵御稻瘟等病原菌侵染过程中，水稻已进化形成了复杂的免疫机制，即由病原菌相关分子模式诱导的基础免疫反应（PAMP-triggered immunity, PTI）和稻瘟病效应因子诱导的免疫反应（Effector-triggered immunity, ETI）。目前相关研究已经鉴定出了很多相关抗稻瘟基因，但这方面的研究仍面临着很多挑战和机遇。我们通过前期的研究发现了一个新的PTI相关基因OsBDR2在稻瘟菌侵染后上调。和野生型株系相比，OsBDR2-RNAi株系均表现出对稻瘟病的抗性。因此我将结合遗传学，生态学和分子生物学等技术对该基因在水稻稻瘟病抗性中的作用机理进行详细解析，以期进一步推进水稻与稻瘟病菌互作的分子机理研究，并为水稻的抗病育种提供借鉴。

受体激酶可以通过激活一些信号通路来调控植物发育或者环境胁迫。水稻基因组编码1000多个RLK，但是目前为止功能研究很清晰得还很少。本项目中，我们从11个受稻瘟病诱导得受体激酶中筛选出一个负调控水稻对稻瘟病抗性得基因命名为BDR1，该基因可以在稻瘟病诱导后快速得表达升高。蛋白互作研究发现BDR1可以和MPK3互作，并且可以磷酸化MPK3来负调控对稻瘟病的抗性。转录组分析发现，稻瘟病处理后，bdr1突变体中JA信号途径和萜类合成途径的相关基因显著上调。进一步研究发现除了二萜，单帖芳樟醇以及倍半萜石竹烯可以直接抑制稻瘟病菌的生长，并且调控它们合成的TPS3和TPS29这两个基因被JA正调控，被BDR1和MPK3负调控。这些发现证明了BDR1-MPK3通过调控JA和TPS来负调控水稻对稻瘟病的抗性。