The role of multiple C2 domain and transmembrane region proteins in mediating tomato development

Multiple C2 domain and transmembrane region proteins (MCTPs) are an evolutionarily conserved family involved in protein trafficking and signal transduction. Although several investigations have demonstrated that MCTPs play crucial roles in plant growth and development, their specific biological functions within tomatoes (Solanum lycopersicum L.) remain predominantly mysterious. In this study, we identify and characterize 14 SlMCTP genes derived from tomatoes. Chromosome mapping, gene structure, phylogenetic connections, and subcellular localization are presented herein. Meanwhile, the varied expression patterns of SlMCTPs within different tissues and under diverse hormonal and NaCl treatment conditions are revealed. Moreover, we find that SlMCTP10, SlMCTP11, and SlMCTP12, which belong to the same clade, display high expression levels at the main stem apex, suggesting their potential functions in shoot development. Furthermore, we knock out the SlMCTP10 gene in tomato using CRISPR-Cas9. The Slmctp10 seedlings exhibit defects in shoot meristem development, manifested by abnormal cotyledons and shorter internodes. Together, our findings offer fundamental insights into the SlMCTP family and uncover the role of SlMCTP proteins in regulating shoot meristem development in tomato plants.