Strigolactone and gibberellin signaling coordinately regulate metabolic adaptations to changes in nitrogen availability in rice

Modern semi-dwarf rice varieties of the“Green Revolution”require a high supply of nitrogen(N)fertilizer to produce high yields.A better understanding of the interplay between N metabolism and plant developmental processes is required for improved N-use efficiency and agricultural sustainability.Here,we show that strigolactones(SLs)modulate root metabolic and developmental adaptations to low N availability for ensuring efficient uptake and translocation of available N.The key repressor DWARF 53(D53)of the SL signaling pathway interacts with the transcription factor GROWTH-REGULATING FACTOR 4(GRF4)and prevents GRF4 from binding to its target gene promoters.N limitation induces the accumulation of SLs,which in turn promotes SL-mediated degradation of D53,leading to the release of GRF4 and thus promoting the expression of genes associated with N metabolism.N limitation also induces degradation of the DELLA protein SLENDER RICE 1(SLR1)in an D14-and D53-dependent manner,effectively releasing GRF4 from competitive inhibition caused by SLR1.Collectively,our findings reveal a previously unrecognized mechanism underlying SL and gibberellin crosstalk in response to N availability,advancing our understanding of plant growth–metabolic coordination and facilitating the design of the strategies for improving N-use efficiency in high-yield crops.