OsNLP3/4-OsRFL module regulates nitrogen-promoted panicle architecture in rice

Abstract

Rice panicles, a major component of yield, are regulated by phytohormones and nutrients. How mineral nutrients promote panicle architecture remains largely unknown. Here, we report that NIN-LIKE PROTEIN3 and 4 (OsNLP3/4) are crucial positive regulators of rice panicle architecture in response to nitrogen (N). Loss-of- function mutants of either OsNLP3 or OsNLP4 produced smaller panicles with reduced primary and secondary branches and fewer grains compared with wild type, whereas their overexpression plants showed the opposite phenotypes. Notably, the OsNLP3/4-regulated panicle architecture was positively correlated with N availability. OsNLP3/4 directly bind to the promoter of OsRFL and activate its expression to promote inflorescence meristem development. Furthermore, OsRFL activates OsMOC1 expression by binding to its promoter. Our findings reveal the novel N- responsive OsNLP3/4-OsRFL-OsMOC1 module that integrates N availability to regulate panicle architecture, shedding light on how nutrient signals regulate panicle architecture and providing candidate targets for the improvement of crop yield.