Genome-wide analysis of KCS genes in tomato and functional characterization of SlKCS8 and SlKCS10 in drought tolerance

KCS, an endogenous cellular enzyme, catalyzes the elongation of fatty acid chains and plays a crucial role in the biosynthesis of plant epidermal wax. Through processes such as transfer, decarboxylation, and fixation, it contributes to plant growth and adaptation to abiotic and biotic stresses. However, the mechanism by which KCS genes participate in the response of tomato plants to driught remains unclear. In this study, 15 SlKCS gene family members were identified in tomato using bioinformatics methods. Comprehensive analyses were conducted on their amino acid sequences, conserved motifs, cis-elements, phylogenetic relationships, duplication events, and collinearity. Transcriptome and qRT-PCR analysis revealed diverse expression patterns of SlKCS genes under abiotic stresses, with SlKCS8 and SlKCS10 displaying significant upregulation during drought conditions. The two genes were localized to the plasma membrane and exhibit tissue-specific expression. Functional studies demonstrated that silencing SlKCS8 and SlKCS10 reduced drought tolerance in tomato by disrupting stomatal closure. Further analysis revealed that the silencing of KCS compromised the drought tolerance of tomato by reducing its capacity to scavenge reactive oxygen species. These findings provide critical insights into the regulatory functions of SlKCS genes, particularly SlKCS8 and SlKCS10, in drought resistance. Additionally, this research offers important genetic resources for developing drought-tolerant tomato cultivars.