GA-DELLA-OsMYB48-1 module-mediated regulation of inorganic phosphate uptake in rice

Inorganic phosphate (Pi) is essential for plant growth and development, yet the regulatory role of gibberellic acid (GA) in Pi uptake in rice remains poorly understood. Here, we identified a major quantitative trait locus (QTL) for phosphorus and nitrogen concentrations, which corresponds to an allele of the Green Revolution gene Semi-Dwarf 1 (SD1), encoding GA20-oxidase, a key enzyme in GA biosynthesis. Through functional analyses of near-isogenic lines, genetic complementation, overexpression, and knockout transgenic lines, we demonstrated that SD1 enhances Pi uptake in rice. The DELLA protein SLR1, a negative regulator of GA signaling, was found to interact with OsMYB48-1, a transcription factor whose expression is induced by Pi availability. Biochemical assays revealed that OsMYB48-1 directly binds to the promoters of OsPT2 and OsPT10, two critical genes involved in Pi transport. Further genetic evidence showed that the knockout of OsMYB48-1 significantly reduced Pi uptake in rice plants. Our findings suggest that the GA-DELLA-OsMYB48-1 module constitutes a previously unrecognized regulatory pathway that enhances phosphate uptake in rice. This discovery provides mechanistic insight into hormone-nutrient crosstalk and offers promising avenues for improving nutrient efficiency and crop productivity.