Genome-Wide Characterization and Expression Pattern Analysis Insights into Plant NBS-LRR Gene Family of Salvia miltiorrhiza

The NBS-LRR genes constitute the largest class of resistance (R) proteins in plants, capable of recognizing pathogen-secreted effectors to trigger immune responses. However, systematic studies of NBS-LRR genes in medicinal plants have not yet been reported. In this study, we performed a comprehensive genome-wide identification and analysis of the NBS-LRR gene family in the medicinal plant Salvia miltiorrhiza. A total of 196 NBS-LRR genes were identified, among which 62 possessed complete N-terminal and LRR domains. Multiple NBS-LRR proteins extracted from other model plants can be classified and distinguished on the phylogenetic tree according to subfamilies CNL, TNL, and RNL. Comparative analysis revealed a marked reduction in the number of TNL and RNL subfamily members within the Salvia species. Analysis of the expression patterns of SmNBS-LRR genes with transcriptomes data revealed a close association between SmNBS-LRRs and secondary metabolism. Promoter analysis demonstrated an abundance of cis-acting elements in SmNBS genes related to plant hormones and abiotic stress. Our study enhances the understanding of the NBS-LRR gene family in medicinal plants and provides a foundation for future functional characterization of the NBS-LRR genes in S. miltiorrhiza and its potential application in disease-resistance breeding.