Natural variation in TaERF-A1 confers semi-dwarf and lodging-resistant plant architecture in wheat.

The introduction of Reduced height (Rht) genes into wheat varieties has been pivotal in developing semi-dwarf plant architectures, significantly improving lodging resistance and harvest indices. Therefore, identifying new Rht gene resources for breeding semi-dwarf wheat cultivars has been a key strategy for ensuring high and stable grain yields since the 1960s. In this study, we report the map-based cloning of TaERF-A1, which encodes an AP2/ERF (APETALA2/ethylene responsive factor) transcription factor that acts as a positive regulator of wheat stem elongation, as a novel gene that regulates plant height and spike length. The natural variant, TaERF-A1, features a Phe (derived from 'Nongda3338') to Ser (derived from 'Jingdong6') substitution at position 178, which significantly reduces the stability of the TaERF-A1 protein. This substitution leads to partially attenuated transcriptional activation of downstream target genes, including TaPIF4 (Triticum aestivum Phytochrome Interacting Factor 4), thereby restricting stem and spike elongation. Importantly, the introgression of the semi-dwarfing allele TaERF-A1 into wheat can significantly enhance lodging resistance, particularly in dense cropping systems. Therefore, our study identifies TaERF-A1 as a new Rht gene resource for breeding semi-dwarf wheat varieties with increased yield stability.