MicroRNA397 promotes rice flowering by regulating the photorespiration pathway.

This article investigates the role of microRNA397 (miR397) and its target gene LACCASE-15 (OsLAC15) in regulating flowering time in rice (Oryza sativa) through modulation of the photorespiration pathway. Overexpression of miR397 accelerates flowering, reduces leaf number on the main stem, enhances photosynthetic intensity, and increases carbohydrate accumulation, while overexpression of OsLAC15 delays flowering and prolongs vegetative growth. OsLAC15 is partially localized in peroxisomes where it regulates photorespiration; elevated CO2 levels can rescue the late flowering phenotype caused by OsLAC15 overexpression. These findings reveal a miR397-OsLAC15 regulatory module that influences rice flowering by affecting photorespiration and carbohydrate metabolism, offering potential strategies for breeding early-flowering, high-yield rice varieties.