PsHB7/12 gene participated in the overwintering process of Pyrus sinkiangensis through negative feedback regulation of ABA.

Pyrus sinkiangensis, a crucial economic fruit tree in Xinjiang, China, experiences winter hardiness that significantly influences its yield and fruit quality. This study aimed to investigate the role of PsHB7/12 in cold resistance of Pyrus sinkiangensis and its regulation of abscisic acid (ABA) signaling. Through physiological assessments and transcriptome analysis, we identified a peak expression of PsHB7/12 in January, which was strongly induced by ABA. We found a correlation between ABA concentrations and changes in water content and soluble protein levels during overwintering process. Further analysis of yeast one-hybrid and the luciferase assay revealed that PsHB7/12 was involved in the negative regulation of ABA signal by inhibiting the expression of PsPYL4. Additionally, the overexpression of the PsHB7/12 may have complex effects on ABA signaling through the modulation of expression of members of the PsPP2Cs family. In summary, PsHB7/12 regulates the ABA signaling pathway through a negative feedback mechanism. These findings reveal the critical role of PsHB7/12 in cold stress adaptation in Pyrus sinkiangensis and provide new molecular markers for breeding stress-resistant fruit trees.