沉默转录因子OsERF7提高水稻对褐飞虱和白背飞虱的抗性
Silencing of OsERF7 enhances the resistance of rice to the brown planthopper Nilaparvata lugens and the white-backed planthopper Sogatella furcifera

为了解植物中特有的转录因子乙烯响应因子（ethylene responsive factor，ERF）在植物诱导抗虫反应中的作用，通过克隆1个水稻ERF转录因子基因OsERF7，并结合分子生物学、反向遗传学及生物测定，探究其在水稻防御褐飞虱Nilaparvata lugens和白背飞虱Sogatella furcifera为害过程中的作用。结果显示，机械损伤处理与褐飞虱产卵雌成虫为害均能在中后期诱导OsERF7的表达。沉默OsERF7能显著降低水稻上褐飞虱及白背飞虱卵的孵化率，并延长褐飞虱卵的发育历期；与野生型水稻相比，褐飞虱和白背飞虱在沉默突变体品系R1和R30上的卵孵化率分别只有野生型水稻上的62.5%~68.3%和68.0%~76.0%，褐飞虱卵的发育历期则延长0.37~0.45 d。沉默OsERF7不影响褐飞虱产卵雌成虫为害诱导的水稻防御相关信号分子—茉莉酸（JA）、水杨酸（SA）、乙烯（ET）和过氧化氢（H2O2）的含量。表明转录因子OsERF7作用于防御相关信号途径的下游，并且负调控水稻对褐飞虱和白背飞虱的抗性。
A kind of plant-specific transcription factors in herbivore-induced plant defenses and a rice ERF gene of OsERF7 was cloned to clarify the role of the ethylene responsive factors (ERFs), and its functions in the resistance of rice to Nilaparvata lugens (rice brown planthopper, BPH) and Sogatella furcifera (white-backed planthopper, WBPH) were explored by combining molecular biology, reverse genetics and bioassays. The results showed that the expression of OsERF7 was induced by mechanical damage and by infestation of gravid BPH females at middle and late stages. Silencing OsERF7 significantly reduced hatching rates of eggs of BPH and WBPH:the hatching rates of BPH and WBPH eggs in lines silencing OsERF7 were 62.5%-68.3% and 68.0%-76.0% of those in wide-type plants. Moreover, silencing OsERF7 also prolonged the developmental duration of BPH eggs by 0.37-0.45 d. Compared to wild-type rice, silencing OsERF7 couldn't affect gravid BPH female-elicited levels of jasmonic acid (JA), salicylic acid (SA), ethylene (ET) and H2O2. The results indicated that OsERF7 functions downstream of defense-related signaling pathways, and negatively regulates the resistance of rice to BPH and WBPH.