Brown planthopper (BPH) is the most destructive insect pest to rice that causes tremendous yield loss each year in rice planting Asia and South-East Asia areas. Compared with traditional chemical-based treatment, utilization of plant endogenous resistance is a more effective and environmental-friendly way for BPH control. Accordingly, quite a few quantitative trait loci (QTLs) for BPH resistance were cloned using forward genetics. However, BPH is apt to change quickly into new biotypes to overcome plant resistance, therefore, new resistance resources and genes are continuously needed. miRNAs are important regulators in both plant development and physiological regulation including immunity, and might be used as effective supplements for BPH resistance QTLs. miR159 is an ancient and conserved miRNA. In this study, we found that each OsMIR159 gene in rice responded to BPH feeding very obviously, and genetic function assay proved them to negatively regulate BPH resistance, with STTM159 showing resistance to BPH, and over expression of OsmiR159d susceptible to BPH. One target genes of OsmiR159, OsGAMYBL2, positively regulated BPH resistance. Further biochemical studies revealed that OsGAMYBL2 could directly bind to the promoter of G-protein γ subunit encoding GS3 gene and repress its expression. And genetically, GS3 responded to BPH feeding promptly and negatively regulated BPH resistance, GS3 over expression plants were susceptible to BPH, while GS3 knock-out plants were resistant to BPH. Thus, we identified new function of OsmiR159–OsGAMYBL2 in mediating BPH response, and revealed a new OsmiR159–G protein pathway that mediates BPH resistance in rice.

褐飞虱（BPH）是对水稻最具破坏性的害虫，每年给亚洲和东南亚水稻种植地区造成巨大的产量损失。与传统的化学处理相比，利用植物内源抗性来控制褐飞虱是一种更有效、更环保的方法。因此，使用正向遗传学克隆了相当多的 BPH 抗性数量性状基因座 (QTL)。然而，BPH容易快速转变为新的生物型来克服植物抗性，因此不断需要新的抗性资源和基因。miRNA是植物发育和包括免疫在内的生理调节的重要调节因子，并且可以用作BPH抗性QTL的有效补充。miR159 是一种古老且保守的 miRNA。在这项研究中，我们发现每个水稻中的OsMIR159基因对BPH取食反应非常明显，遗传功能分析证明其对BPH抗性具有负调控作用，其中STTM159表现出对BPH的抗性，而OsmiR159d对BPH易感。OsmiR159 的靶基因之一OsGAMYBL2正向调节 BPH 抵抗。进一步的生化研究表明，OsGAMYBL2可以直接结合编码GS3基因的G蛋白γ亚基的启动子并抑制其表达。并且从遗传上看，GS3对BPH取食反应迅速，并负向调节BPH抗性，GS3过表达植物对BPH敏感，而GS3敲除植物对褐飞虱具有抗性。因此，我们鉴定了OsmiR159-OsGAMYBL2在介导BPH反应中的新功能，并揭示了介导水稻BPH抗性的新OsmiR159-G蛋白途径。