Transcription factors (TFs) play essential roles in transcriptional reprogramming during activation of plant immune responses to pathogens. OsSPL10 (SQUAMOSA promoter binding protein-like10) is an important TF regulating trichome development and salt tolerance in rice. Here we report that knockout of OsSPL10 reduces whereas its overexpression enhances rice resistance to blast disease. OsSPL10 positively regulates chitin-induced immune responses including reactive oxygen species (ROS) burst and callose deposition. We show that OsSPL10 physically associates with OsJAmyb, an important TF involved in jasmonic acid (JA) signaling, and positively regulates its protein stability. We then prove that OsJAmyb positively regulates resistance to blast. Our results reveal a molecular module consisting of OsSPL10 and OsJAmyb that positively regulates blast resistance.

Plant trichomes are a specialized cellular tissue that functions in resistance to biotic and abiotic stresses. In rice, three transcription-factor genes: OsWOX3B, HL6, and OsSPL10, have been found to control trichome development. Although studies have shown interactions between the three genes, their full relationship in trichome development is unclear. We found that the expression levels of OsWOX3B and HL6 were both reduced in OsSPL10-knockout plants but increased in OsSPL10-overexpression plants, suggesting that OsSPL10 positively regulates their expression. Physical interaction between OsSPL10 and OsWOX3B was found both in vivo and in vitro and attenuated their abilities to bind to the promoter of HL6 to activate its transcription. This mechanism may regulate trichome length by adjusting the expression of HL6. A rice gene network regulating trichome development is proposed.