Comprehensive analysis of the SmPIN gene family in Salix matsudana: roles in growth, development, and stress adaptation

Auxin is essential for a wide range of plant growth and developmental processes, including morphogenesis and adaptive responses. It primarily exerts its effects by influencing cell morphogenesis and enhancing stress tolerance. The transmembrane transport of auxin is facilitated by PIN-FORMED (PIN) proteins, which are key in regulating the directional flow of auxin between cells and its accumulation within them. Until now, the role of the PIN gene family in Salix matsudana (SmPIN) morphogenesis and its environmental resilience has not been explored. In this study, we identified 28 SmPINs in the S. matsudana genome and our findings revealed some significant unique features of SmPINs in terms of structure, function, and regulation. Additionally, SmPIN1e, SmPIN1h, and SmPIN3c, identified as differentially expressed genes (DEGs), played crucial roles in salt response, while SmPIN3b and SmPIN3d were vital for adaptation to submergence stress. Moreover, SmPIN2d, SmPIN2c, and SmPIN5b were involved in root generation from callus through the MAPK signaling pathway, highlighting the unique regulatory mechanisms of SmPINs during various developmental processes. Overall, SmPINs are crucial for the growth, development, and stress adaptation of S. matsudana, offering insights into plant morphogenesis and stress responses.