Identification of perennial ryegrass CDPK gene family and function exploration of <i>LpCDPK27</i> upon salt stress

Calcium serves as a pivotal second messenger in the response to both abiotic and biotic stresses. Calcium-dependent protein kinase (CDPK) plays a significant role in plant development, growth, and adaptation to environmental stresses. In our research, 28 <i>LpCDPKs</i> were computationally identified in <i>Lolium perenne</i> and divided into Groups I−IV based on phylogenetic relationships. Six genes with promoter regions containing elements related to abiotic stress responsiveness were selected to investigate further whether they were stress-related <i>LpCDPKs</i>. The qRT-PCR analysis revealed that most <i>LpCDPKs</i> responded to various abiotic stresses and phenotypic validation of overexpressed yeast under stress conditions confirmed these findings. Notably, <i>LpCDPK27</i> was strongly induced by salt stress, and its overexpression in Arabidopsis significantly enhanced salt tolerance. <i>LpCDPK27</i> overexpressing lines exhibited lower Na⁺ content, higher K⁺ content, and increased expression of stress-related genes compared to wild-type plants. Collectively, these results provide essential insights into the evolution and function of <i>LpCDPKs</i> and offer a valuable resource for future research on the roles of CDPKs in the growth, development, and stress responses of <i>Lolium perenne</i>.