OsRCI-1-Mediated GLVs Enhance Rice Resistance to Brown Planthoppers

Green leaf volatiles (GLVs) play pivotal roles in plant anti-herbivore defense. This study investigated whether the rice 13-lipoxygense geneOsRCI-1is involved in GLV production and plant defense in rice. The overexpression ofOsRCI-1(oeRCIlines) in rice resulted in increased wound-induced levels of two prominent GLVs,cis-3-hexen-1-ol andcis-3-hexenal. In a previous study, we found that the overexpression ofOsRCI-1reduced the colonization by the rice brown planthopper (BPH,Nilaparvata lugens) but increased the attractiveness to the egg parasitoidAnagrus nilaparvataecompared to wild-type (WT) plants. This study found that whencis-3-hexen-1-ol, but notcis-3-hexenal, was added to WT plants, it could change the BPH’s colonization preference, i.e., more BPHs preferred to colonize theoeRCIlines. The exogenous application ofcis-3-hexen-1-ol orcis-3-hexenal to BPH-infested WT plants could weaken or overturn the preference ofA. nilaparvataeforoeRCIlines. However, field experiments revealed that onlycis-3-hexenal was attractive to the parasitoid and increased the parasitism rates of BPH eggs. These results indicate thatOsRCI-1is involved in rice GLV production and therefore modulates both direct and indirect defense in rice.