Gene prediction and evolutionary characterization of heat shock transcription factors in Salvia miltiorrhiza

Abstract Background Heat shock transcription factors (HSFs) serve as central regulators in plants and enable adaptations to dynamic environmental changes, such as heat stress. Salvia miltiorrhiza is an important medicinal plant model. However, various biotic and abiotic stresses, pathogen infections, and degeneration of elite cultivars limit the yield and quality of S. miltiorrhiza. Therefore, it is important to predict and characterize the stress resistance genes of S. miltiorrhiza and clarify potential molecular mechanisms for genetic improvement. However, the knowledge of HSF genes in S. miltiorrhiza is limited. Methods Thus, we performed a genome-wide analysis of HSF genes in S. miltiorrhiza . Results Using high-quality genome sequences, we predicted 34 HSF genes distributed unevenly across eight chromosomes. Twenty-three genes were segmentally duplicated, suggesting that in S. miltiorrhiza , segmental duplications have significantly contributed to the expansion of the HSF gene family. The predicted genes were divided into 15 phylogenetic groups, among which the sequence characteristics were relatively well conserved. The Ka/Ks ratios indicated that duplicated HSF genes underwent negative selection. Most of the HSF genes displayed different expression characteristics under drought stress and salicylic acid induction. This study provides valuable data that may inform further functional studies of HSF genes in S. miltiorrhiza .