Genome-wide identification and expression analysis of HSF gene family in response to salt stress in Cyclocarya paliurus

To investigate the regulatory mechanism of HSF transcription factors in Cyclocarya paliurus under salt stress, and provide genetic targets for enhancing stress resistance.

A genome-wide identification of HSF gene family members was performed using C. paliurus genomic data, followed by analysis of their physicochemical properties, gene structures, and phylogenetic relationships. Four salt concentration treatments were applied, and transcriptomic analysis was conducted to investigate CpHSF expression patterns under salt stress.

Thirty CpHSF members were identified, distributed across 14 chromosomes. The encoded proteins ranged in length from 197 to 611 amino acids (aa), with molecular weights of 21.6-68.1 kDa and hydrophilicity coefficients from -0.936 to -0.424. Subcellular localization predicted nuclear localization. Promoter analysis revealed 13 cis-acting elements, including gibberellin-response elements, auxin-response elements, and MYB-binding sites associated with flavonoid biosynthesis regulation. Transcriptomic data showed upregulation of most CpHSF under salt stress, with 13 genes (e.g., CpHSF5, CpHSF6, CpHSF11, CpHSF12) exhibiting higher expression levels at 30 days than at 15 days. Conversely, CpHSF11 and CpHSF28 were downregulated. Protein-protein interaction analysis identified associations between CpHSF22/CpHSF28/CpHSF30 and stress-related proteins (SPH18, HSBP, HSP22, CLPB1).

The CpHSF family members predominantly act as positive regulators of salt stress adaptation, while CpHSF11 and CpHSF28 play a negative regulatory role in this process.