Knockout of OsWRKY71 impairs Bph15-mediated resistance against brown planthopper in rice

Abstract

The <i>Bph15</i> gene, known for its ability to confer resistance to the brown planthopper (BPH; <i>Nilaparvata lugens</i> Stål), has been extensively employed in rice breeding. However, the molecular mechanism by which <i>Bph15</i> provides resistance against BPH in rice remains poorly understood. In this study, we reported that the transcription factor <i>OsWRKY71</i> was highly responsive to BPH infestation and exhibited early-induced expression in <i>Bph15</i>-NIL (near-isogenic line) plants, and OsWRKY71 was localized in the nucleus of rice protoplasts. The knockout of <i>OsWRKY71</i> in the <i>Bph15</i>-NIL background by CRISPR-Cas9 technology resulted in an impaired <i>Bph15</i>-mediated resistance against BPH. Transcriptome analysis revealed that the transcript profiles responsive to BPH differed between the <i>wrky71</i> mutant and <i>Bph15</i>-NIL, and the knockout of <i>OsWRKY71</i> altered the expression of defense genes. Subsequent quantitative RT-PCR analysis identified three genes, namely sesquiterpene synthase <i>OsSTPS2</i>, EXO70 family gene <i>OsEXO70J1</i>, and disease resistance gene <i>RGA2</i>, which might participate in BPH resistance conferred by <i>OsWRKY71</i> in <i>Bph15</i>-NIL plants. Our investigation demonstrated the pivotal involvement of <i>OsWRKY71</i> in <i>Bph15</i>-mediated resistance and provided new insights into the rice defense mechanisms against BPH.