Genome-Wide Identification of the Heat Shock Transcription Factor Gene Family in Rosemary (Salvia rosmarinus)

Rosemary (Salvia rosmarinus) is a world-famous plant frequently subjected to various environmental stresses. Heat Shock Transcription Factor (HSF) has been shown to be essential for plant growth and for resistance to environmental stresses. This study utilized bioinformatics techniques to identify the SrHSF gene family in the rosemary genome. A total of 49 SrHSFs were detected, unevenly distributed across 12 chromosomes. The SrHSF genes were classifiable into 3 subfamilies and contained in 14 subgroups. They were relatively conserved during the evolutionary process based on gene structure and conserved motif analysis. There were 22 kinds of cis-acting elements in the promoter regions of SrHSF genes, mostly related to hormones, stress, growth, and development. The interactions among 16 highly conserved SrHSF proteins were also identified. Gene collinearity analysis showed that 51 segmental duplication events were undergone among 41 SrHSF genes. Ka/Ks ratios were all less than 1, suggesting a purifying selection of SrHSF homologous genes. The expression pattern of SrHSF genes revealed that the majority of them are highly expressed in the secondary stems. After 0.1% MeJA treatment, SrHSF36 and SrHSF11 showed a significant upregulation in leaves. This research provides valuable insights into the functions and regulatory mechanisms of the SrHSF gene family.