The crucial roles of the lipase-like protein enhanced disease susceptibility 1 (EDS1) and phytoalexin deficient 4 (PAD4) in disease resistance in Arabidopsis have been identified. However, their function in rice (Oryza sativa L.) resistance to brown planthopper (BPH, Nilaparvata lugens Stål), the most notorious pest of rice, remains unknown. In this study, the transcript levels of OsEDS1 and OsPAD4 were rapidly altered by BPH infestation. Mutation in either OsPAD4 or OsEDS1 resulted in increased rice susceptibility to BPH, which was associated with increased honeydew excretion and an increased host preference of BPH. Furthermore, mutation in either OsPAD4 or OsEDS1 led to decreased basal levels of salicylic acid (SA) and jasmonic acid (JA) in the absence of BPH, along with the depressed expression of the defense-responsive genes OsPAL, OsICS1, OsPR1a, OsLOX1, OsAOS1 and OsJAZ11 involved in SA and JA biosynthesis and signaling. The BPH infestation-mediated elevation of SA levels and the expression of SA biosynthesis and signaling genes was dampened in eds1 and pad4 plants, whereas BPH infestation-mediated depressions of JA levels and the expression of JA biosynthesis and signaling genes were reversed in eds1 and pad4 plants. Taken together, our findings indicated that both OsPAD4 and OsEDS1 positively regulate rice resistance to BPH.

Keywords: Oryza sativa; OsEDS1; OsPAD4; brown planthopper.

在拟南芥（Arabidopsis）中，类脂肪酶蛋白增强疾病敏感性1（EDS1）和植物杀菌素缺乏4（PAD4）在病害抗性中的关键作用已被确认。然而，在水稻（Oryza sativa L.）对褐飞虱（BPH, Nilaparvata lugens Stål，最著名的稻田害虫）的抗性中，OsEDS1和OsPAD4的功能仍不清楚。在这项研究中，我们发现水稻在遭受褐飞虱侵害时，OsEDS1 和 OsPAD4 的转录水平迅速改变。无论是OsPAD4还是OsEDS1的突变都会导致水稻对BPH的抗性降低，并且与BPH分泌蜜露量增加和寄主偏好度增强有关。此外，无论是在没有BPH侵害的情况下，OsPAD4或OsEDS1的突变均会导致水杨酸（SA）和茉莉酸（JA）的基础水平降低，并且涉及SA和JA生物合成和信号传导的相关防御响应基因OsPAL, OsICS1, OsPR1a, OsLOX1, OsAOS1 和 OsJAZ11 的表达量降低。在和植物中，BPH侵害引起的SA水平升高及相关的生物合成和信号传导基因的表达减弱，而BPH侵害导致的JA水平下降及相关的生物合成和信号传导基因的表达则逆转了。总的来说，我们的研究结果表明OsPAD4和OsEDS1在水稻抵抗褐飞虱中起着积极调控作用。

关键词： 水稻；OsEDS1；OsPAD4；褐飞虱。