茉莉素调控β-D-葡聚糖介导的水稻褐飞虱抗性的分子机理

Brown planthopper (BPH) is one of the most destructive pest of rice. At present, the molecular regulation mechanism of rice response to BPH stress remains poorly understood. Our preliminary data show that the endogenous contents of Jasmonates (JAs) are significantly Brown planthopper (BPH) is one of the most destructive pest to rice production. At present, molecular mechanisms in regulating response to BPH stress in rice by JAs remains unclear. Our preliminary data show that the endogenous contents of Jasmonates (JAs) are significantly accumulated after BPH treatment, and the deficient mutants in both JAs biosynthesis and signal transduction (oslox2-cas9 and oscoi1a/1b-cas9 lines) are more sensitive to BPH stress. Additionally, metabolomics analysis indicate that β-D-glucan is an important biomarker in regulating the response to BPH stress in rice by JAs signal. Moreover, the results of promoter analysis reveale that the β-D-glucan synthesis genes CsLF2 and CsLF6 are potential target genes of OsMYC2, which is the key transcription factor of JAs signal. These results point to the possibility that JAs may regulate β-D-glucan synthesis through OsMYC2 then mediates BPH resistance of rice. By genetic and biochemical approaches, we further intend to elucidate the mechanism of how OsMYC2 interacts with β-D-glucan synthesis pathway to regulate BPH stress response in rice. It is expected that the research results would have important scientific significance and potential practice application value for deeply understanding the JAs signal pathway and BPH resistance in rice.

褐飞虱是水稻生产中最具毁灭性的害虫之一，目前对茉莉素调控水稻应答褐飞虱胁迫的分子机理还不清楚。申请人前期研究显示，褐飞虱取食显著诱导茉莉素含量的积累，茉莉素合成和信号缺失突变体oslox2-cas9和oscoi1a/1b-cas9植株对褐飞虱耐受性更为敏感。代谢组学分析表明β-D-葡聚糖是茉莉素信号调控水稻应答褐飞虱胁迫的重要代谢标志物。启动子分析结果显示，β-D-葡聚糖合成基因CsLF2和CsLF6是茉莉素信号关键转录因子OsMYC2的潜在靶基因。因此推测，茉莉素信号可能通过OsMYC2调控β-D-葡聚糖合成，从而介导水稻对褐飞虱抗性反应。本项目拟通过遗传学和生物化学等手段，深入解析转录因子OsMYC2参与的水稻应答褐飞虱胁迫与β-D-葡聚糖合成途径相互作用的分子机理。预期研究成果对于深入理解水稻茉莉素信号通路和褐飞虱抗性的分子机理具有重要的科学意义和潜在的实践应用价值。

褐飞虱（Brown planthopper, BPH, Nilaparvata lugens）是对水稻（Oryza sativa）危害最大的害虫，严重影响其产量。目前关于水稻抗褐飞虱的遗传分子机制已经得到深入的解析，但是，对于植物细胞壁主要成分调控水稻对褐飞虱抗性的分子机理仍知之甚少。在本研究中，通过基于质谱的代谢组学分析，发现禾本科特有的细胞壁成分β-D-葡聚糖（β-1,3;1,4-D-glucan, β-D-Glucan）是受茉莉素信号调控参与褐飞虱抗性反应的重要代谢物。在温室和田间条件下，过表达β-D-葡聚糖合成相关的CsLF （Cellulose Synthase-Like F）家族基因OsCslF6均能够提高植株的褐飞虱抗性。水稻茉莉素途径重要转录因子OsMYC2通过直接结合OsCslF6基因的启动子调控其转录水平促进β-D-葡聚糖的积累从而提高水稻植株对褐飞虱的抗性。总的来说，本研究揭示了β-D-葡聚糖合成酶基因OsCslF6基因在调控水稻对褐飞虱抗中的重要作用，深入解析了茉莉素调控β-D-葡聚糖合成介导水稻对褐飞虱抗性反应的分子机理，丰富了水稻对褐飞虱抗性反应的调控网络机制。