OsEDS1 and OsPAD4 Are Involved in Brown Planthopper Resistance in Rice

The crucial roles of the lipase-like protein enhanced disease susceptibility 1 (EDS1) and phytoalexin deficient 4 (PAD4) in disease resistance in <i>Arabidopsis</i> have been identified. However, their function in rice (<i>Oryza sativa</i> L.) resistance to brown planthopper (BPH, <i>Nilaparvata lugens</i> Stål), the most notorious pest of rice, remains unknown. In this study, the transcript levels of <i>OsEDS1</i> and <i>OsPAD4</i> were rapidly altered by BPH infestation. Mutation in either <i>OsPAD4</i> or <i>OsEDS1</i> 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 <i>OsPAD4</i> or <i>OsEDS1</i> 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 <i>OsPAL</i>, <i>OsICS1</i>, <i>OsPR1a</i>, <i>OsLOX1</i>, <i>OsAOS1</i> and <i>OsJAZ11</i> 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 <i>eds1</i> and <i>pad4</i> plants, whereas BPH infestation-mediated depressions of JA levels and the expression of JA biosynthesis and signaling genes were reversed in <i>eds1</i> and <i>pad4</i> plants. Taken together, our findings indicated that both OsPAD4 and OsEDS1 positively regulate rice resistance to BPH.