A natural allele of TaSCE1-A1 confers drought resistance in wheat

Drought stress threatens global wheat productivity, yet the genetic and molecular mechanisms underlying drought resilience remain incompletely understood. Here we identify TaSCE1-A1, which encodes a SUMO-conjugating enzyme, as a positive regulator of drought resistance through genome-wide association studies. In arid regions, an evolutionary G-to-A transition in the promoter confers elevated TaSCE1-A1 expression through disruption of TaBPC1-mediated transcriptional repression. Prime-edited and near-isogenic lines harbouring elite alleles show improved drought resilience, confirming its functional significance. Moreover, TaSCE1-A1 mediates SUMOylation of TaBAP1/2, thereby enhancing its protein stability, which in turn modulates the ABA pathway to facilitate stomatal closure under drought conditions. Evolutionarily, this adaptive allele originated in tetraploid wheat and underwent positive selection during hexaploid wheat domestication. Our findings reveal a drought resistance pathway shaped by evolutionary selection, offering molecular targets for breeding drought-resilient wheat varieties.