Functional Analysis Of Herbivore Resistance-related Gene OsHRG-7 In Rice

When attacked by herbivores,plants produce defense responses immediately.It has been reported that OsERF3 functions as an important early responsive factor in herbivore-induced plant defense responses,which regulates the resistance in rice to the striped stem borer(SSB,Chilo suppressalis)and brown planthopper(BPH,Nilaparvata lugens)by modulating the biosynthesis of jasmonic acid(JA)and H2O2.Our previous studies identified a protein that interacts with OsERF3;we named the protein-encoding gene as herbivore resistance-related gene 7(OsHRG-7).Through transgenic technology,we obtained rice lines with silencing of OsHRG-7,and explored the function of OsHRG-7 in herbivore-induced rice defenses.Aligning the gene sequence on NCBI revealed that OsHRG-7 locates on chromosome 11 of the rice genome and encodes an unknown protein.The transcript level of OsHRG-7 was significantly up-regulated in response to mechanical wounding and infestation of SSB larva or gravid BPH females,whereas treatment with salicylic acid did not enhance the transcript level of OsHRG-7.Compared with wild type(WT)plants,lines silencing OsHRG-7 significantly increased plant weights.Bioassays revealed that silencing OsHRG-7 increased the feeding preference of BPH at the early stage(<8h),but significantly reduced the preference at the later stage(8-48h).Moreover,silencing OsHRG-7 reduced the oviposition preference and egg hatching rate of BPH and the mass of SSB larvae.Chemical analysis showed silencing OsHRG-7 did not significantly affect BPH-induced levels of jasmonic acid,jasmonic acid-isoleucine,salicylic acid,ethylene,and hydrogen peroxide in rice.In summary,OsHRG-7 gene is a responsive gene in herbivore-induced defense response in rice,and plays a certain role in regulating the resistance of rice to BPH and SSB.Further research should elucidate the mechanisms underlying OsHRG-7-mediated herbivore resistance in rice.