Versatile roles of CrRLK1L proteins in crop adaptation to biotic and abiotic stresses

Drastic environmental changes, including diverse biotic and abiotic stresses, pose serious threats to global crop production. To perceive and respond to external stimuli, plants rely on plasma membrane–localized receptor-like kinases (RLKs), which activate downstream signaling pathways mediating stress adaptation. Catharanthus roseus receptor-like kinase 1-like (CrRLK1L) proteins constitute a distinct and widely conserved subfamily of RLKs capable of recognizing rapid alkalinization factor (RALF) peptides. Acting as central signaling hubs, CrRLK1L proteins play essential roles in plant growth, development, reproduction, and responses to both biotic and abiotic stresses. This review summarizes the classification and biological functions of CrRLK1L proteins, with particular emphasis on their regulatory roles and underlying molecular mechanisms in crop responses to biotic and abiotic stresses. In addition, we discuss the potential applications of CrRLK1L genes in enhancing crop stress resistance and promoting agricultural sustainability.