Overexpression of ZmSPL12 confers enhanced lodging resistance through transcriptional regulation of D1 in maize

Semidwarf plant architecture contributes to dense planting, improving lodging resistance and production The applications of semidwarf genes such as sd1 and Rht1 involved in the biosynthesis or regulation of GA signaling pathway resulted in the first "green revolution"in rice and wheat. However, biosynthesis genes in maize such as D1 (ZmGA3ox2), that can efficiently reduce plant stature but have severe negative yield traits. Here, we identified ZmSPL12 conferring semidwarf plant stature and logging resistance. ZmSPL12 specifically binds to the promoter of D1 and repressing the transcription of D1. Detailed phenotypic analysis of transgenic materials showed that knocking out ZmSPL12 increased plant height and lengthened internodes, whereas overexpressing ZmSPL12 decreased plant architecture and shortened internodes, caused by decreased cell elongation. Helping explain these observations, we found expression level of D1 and endogenous bioactive GA content decreased significantly in ZmSPL12-OE internodes. Nevertheless, the semidwart phenotype was restored by exogenous application of GA3. ZmSPL12-OE plants enhance high-density maize yields and logging resistance. Introgressing the ZmSPL12 overexpression fragment into modern inbreds and confering logging resistance of maize. Our study reveals a direct functional link between ZmSPL12 and D1 that plants use to manage endogenous GA level and strongly suggests that ZmSPL12 can be harnessed as a elite resource for developing high-density-tolerant crop varieties.