Dual roles of SmCLE25 peptide in regulating stresses response and leaf senescence

Peptide hormones play crucial roles as signaling regulators in plant development and environmental adaptation. This study identified the Salvia miltiorrhiza CLE peptide SmCLE25, which is involved in regulating leaf senescence and multiple stress responses. SmCLE25 transcription is upregulated by ABA, JA, high salinity, and drought stresses. Application of synthetic SmCLE25 mature peptide significantly enhanced S. miltiorrhiza resistance to salt and drought tolerance. Overexpression of SmCLE25 in Arabidopsis thaliana delayed senescence and enhanced drought resistance. Seed germination assays demonstrated that elevated SmCLE25 expression enhanced germination efficiency under salt and drought conditions. Mechanistic analysis revealed that SmCLE25 peptide reduces reactive oxygen species (ROS) accumulation under stress by downregulating ROS biosynthesis-related genes RbohC and RbohE. This study provides novel insights into the regulatory mechanisms of peptide signaling in leaf senescence and stress adaptation to salinity and drought.