Abstract
BACKGROUND: Tomatoes are renowned for their popularity and nutritional value across the globe, yet their production and quality face significant challenges from various biotic stresses in their growing environments. Kiwellin (KWL) has been implicated in plant disease resistance. However, our comprehension of this gene family in plants is still remarkably insufficient. METHODS: We conducted a comprehensive genomic analysis of the KWL gene family in tomatoes. The tertiary structures of SlKWLs were predicted by AlphaFold2. EMBOSS was used for codon analysis. RNA-seq and RT-qPCR analysis were performed to explore the expression profile of SlKWLs. RESULTS: Our findings identified 12 distinct SlKWL members distributed across four chromosomes within the tomato genome. By examining their gene structure, conserved motifs, functional domains, and phylogenetic relationships, we elucidated the complex evolutionary relationships and potential functions of these genes. Notably, we identified numerous cis-regulatory elements within the promoter regions of the SlKWL genes which are associated with responses to both abiotic and biotic stresses, as well as hormone signaling pathways. This finding strongly implies that SlKWLs are integral to plant growth and adaptation to diverse stress conditions. Furthermore, RNA-seq and RT-qPCR analysis revealed an upregulation of five SlKWLs expressed subsequent to Phytophthora infestans infection. Particularly, SlKWL2 and SlKWL3 exhibited substantially elevated expression levels, underscoring their active involvement in biotic stress responses. CONCLUSIONS: Collectively, these findings advance our comprehension of the SlKWL gene family and provide a robust foundation for future investigations into the roles of SlKWL genes in tomato stress responses.