Identification and response to abiotic stress of the alfalfa serine carboxypeptidase-like protein gene family

A class of acyltransferase enzymes known as serine carboxypeptidase-like (SCPL) proteins play a pivotal role in plant growth, development, and responses to stress. While SCPL proteins have been extensively studied in various plants, their biological functions in alfalfa remain largely unexplored. In this study, 39 <italic>SCPL</italic> gene family members were identified in alfalfa and classified into three subgroups (Groups I–III). Their chromosomal structure and homology were also analyzed. Gene transcription levels were analyzed, revealing that six genes were expressed in a few specific tissues, while the remaining 33 <italic>MsSCPL</italic> were expressed throughout the tissues. Additionally, analysis of <italic>cis</italic>-acting elements revealed that the <italic>SCPL</italic> gene family contains components linked to abiotic stress. Meanwhile, transcriptome analysis revealed that 11, 16, and 14 members of <italic>MsSCPL</italic> gene family were found to respond to three stresses, respectively (cold, salt, and drought), in addition to <italic>MsSCPL31/35,</italic> which responded to all stresses at the same time. The transcriptome results were further validated by RT-qPCR. This highlights the role of <italic>MsSCPL31</italic>/<italic>35</italic> in abiotic stress response, suggesting their importance for plant adaptation mechanism. These results could be crucial for understanding the mechanisms behind alfalfa <italic>SCPL</italic> gene function.