Genetic identification and evolutionary features research: Genome-wide analysis of heat shock transcription factors in Salvia miltiorrhiza

Salvia miltiorrhiza , a medicinal plant of significant economic and therapeutic importance, particularly in China, is increasingly threatened by environmental stressors and habitat depletion. Heat shock transcription factors (HSFs), which play a crucial role in plant adaptation to environmental stresses, including heat, remain insufficiently studied in this species. In this study, we conducted a genome-wide analysis of HSF genes in S. miltiorrhiza using the recently reannotated high-quality reference genome. Our analysis identified 34 HSF genes unevenly distributed across eight chromosomes. Notably, 20 of these genes exhibited segmental duplication, highlighting its key role in the expansion of the HSF gene family. Phylogenetic classification categorized these genes into 15 distinct groups, all of which shared conserved sequence characteristics. Evidence of purifying selection was observed in duplicated HSF genes, suggesting functional constraints that maintain their roles in stress adaptation. Furthermore, most HSF genes exhibited distinct expression patterns under drought stress and salicylic acid treatment, indicating their active involvement in stress response mechanisms. This study significantly enhances our understanding of the HSF gene family in S. miltiorrhiza and provides a foundation for future functional studies aimed at improving the plant's stress tolerance. • 34 HSF genes in S. miltiorrhiza exhibit an uneven chromosomal distribution. • Fifteen phylogenetic HSF groups under purifying selection were identified. • Thirteen segmental duplication events drive the expansion of the HSF gene family. • Drought and SA induce shifts in HSF expression, implicating stress responses.