In silico genomic characterization, classification, and expression profiling of the LRR-RLK family in Lactuca sativa under stress and developmental conditions

Leucine-rich repeat receptor-like kinases (LRR-RLKs) constitute the largest receptor kinase family in plants and are involved in diverse processes related to development, environmental perception, and signal transduction. Despite their relevance, the LRR-RLK gene family has not been systematically characterized in Lactuca sativa. In this study, a genome-wide identification and integrative characterization of LsLRR-RLK genes was performed using curated bioinformatic pipelines. Phylogenetic relationships, protein architecture, conserved motifs, biochemical properties, gene structure, chromosomal distribution, duplication patterns, syntenic relationships, cis-regulatory elements, and transcriptomic profiles were comprehensively analyzed. A total of 269 high-confidence LRR-RLK genes were identified and classified into established subfamilies, revealing marked subfamily-specific patterns of structural organization, regulatory architecture, and transcriptional behavior. Expression analyses across developmental stages and multiple environmental conditions demonstrated widespread but heterogeneous transcriptional regulation within the family. Collectively, this work provides a detailed genomic and functional overview of the LRR-RLK gene family in L. sativa, establishing a structured reference for comparative and exploratory studies of receptor-like kinases in plants.