The ethylene responsive factor TaERF-2 A activates gibberellin 2-oxidase gene TaGA2ox2-3B expression to enhance seed dormancy in wheat

The plant hormone gibberellin (GA) plays a key role in breaking seed dormancy, but the underlying regulatory mechanism is not fully understood. Here, we reported TraesCS3B02G166100 (named TaGA2ox2-3B), encoding a GA metabolism enzyme GA2ox family member, to be differentially expressed in strong- and weak-dormancy wheat seeds during germination. We confirmed that the ERF transcription factor TaERF-2 A directly bound to the TaGA2ox2-3B promoter and enhanced its transcription. Germination tests indicated that TaERF-2 A positively regulated seed dormancy in wheat. Additionally, 12 mutations were identified within the promoter and coding regions of TaGA2ox2-3B when comparing strong- and weak-dormancy wheat varieties. Six molecular markers were developed to verify correlations between these mutations and seed dormancy. Transgenic experiments verified the potential of the TaGA2ox2-3B^+2246-A allele to enhance seed dormancy. Physiological and biochemical analyses indicated that the TaERF-2 A-TaGA2ox2-3B module modulated seed dormancy by influencing GA metabolism and signaling pathways. Collectively, this study revealed the molecular mechanism of GA regulating seed dormancy, and identified genetic resources and molecular markers to breed wheat varieties with preharvest sprouting resistance.