OsWRKY113 undermines jasmonic acid-dependent immune responses to Fusarium fujikuroi.

Abstract

Main conclusion: OsWRKY113 functions as a negative regulator of rice immunity against Fusarium fujikuroi by attenuating jasmonic acid-mediated immune responses, unveiling its previously uncharacterized role within the OsWRKY transcription factor family. The fungal pathogen Fusarium fujikuroi is a major causal agent of bakanae disease in rice (Oryza sativa), a globally important staple crop. WRKY transcription factors are key regulators in the interaction between rice and this pathogen. However, the specific OsWRKY genes that contribute to rice susceptibility to F. fujikuroi remain uncharacterized. In this study, we identify OsWRKY113 as a negative regulator of resistance to F. fujikuroi. OsWRKY113 was localized exclusively in the nucleus, and its expression was induced following F. fujikuroi infection. Transgenic rice lines constitutively expressing OsWRKY113 exhibited impaired jasmonic acid (JA) biosynthesis and signaling upon F. fujikuroi challenge, accompanied by a significant downregulation of JA-responsive pathogenesis-related (PR) genes, including OsPR9. Notably, exogenous application of methyl jasmonate reversed this enhanced susceptibility and restored the expression of JA-associated defense genes in the OsWRKY113-expressing plants. Collectively, these findings show that OsWRKY113 increases rice susceptibility to F. fujikuroi by suppressing JA-mediated immune responses.