A wheat NAC transcription factor, TaNAC018-7D, regulates seed dormancy and germination by binding to the GA biosynthesis gene TaGA7ox-A1

Abstract

Pre-harvest sprouting (PHS) reduces grain yield and quality and poses a serious threat to global wheat production. Seed dormancy and germination are closely related to PHS resistance. However, the intricate regulatory processes governing seed dormancy and germination remain largely unknown. Here, we reported that a NAC transcription factor gene (TaNAC018–7D) is highly expressed in weak-dormancy wheat cultivar Jing 411 compared with a strong-dormancy landrace Hongmangchun 21 during seed germination. Germination tests revealed that TaNAC018–7D negatively regulates seed dormancy and positively mediates germination in transgenic lines of Arabidopsis and rice, and wheat mutants induced by ethyl methane sulfonate in the Jing 411 background. Subcellular localization analysis indicated that TaNAC018–7D is located in the nucleus and cytoplasm. Physiological, biochemical, and molecular experiments indicated that TaNAC018–7D interacts with the promoter of the GA biosynthesis gene TaGA7ox-A1 and activates its expression, thereby shortening seed dormancy and promoting germination. In summary, this study provides a new target gene for improving wheat PHS resistance, and improves the understanding of the complex regulatory network of PHS resistance.