Abstract：Heat shock transcription factors (Hsfs) are important components in response to stress signals. Carnation (Dianthus caryophyllus) variety ‘fancy’ was used as experimental material to clone the complete coding sequence of DcHsfA4 (GenBank No. MN096327). The full length of the sequence was 1 173 bp and encoded 390 amino acid residues. Bioinformatics analysis showed that the molecular formula of DcHsfA4 protein was C1963H3051N577O625S8, the molecular weight was 44.99 kD, the theoretical isoelectric point was 5.48, the fat coefficient was 71.95, and the instability coefficient was 49.72, which was predicted to be unstable protein. Hydrophobic/hydrophilic prediction indicates that the DcHsfA4 protein was a hydrophilic protein. Protein transmembrane analysis revealed that DcHsfA4 was a non-transmembrane protein. Secondary structure predictions showed that the amino acid composition of DcHsfA4 included α-helix (42.56%), extended chain (6.67%), β-sheet (3.08%), and irregular curl (47.69%), which belonged to an irregular structure. Amino acid sequence alignment revealed that DcHsfA4 contained a highly conserved DNA binding domain and, in addition, two hydrophobic hepated repeat, a nuclear localization signal sequence and a C-terminal activation domain. Phylogenetic analysis indicated that DcHsfA4 had the highest homology with Arabidopsis AtHsfA4. The expression characteristics of DcHsfA4 under different abiotic stress treatments were analyzed by real-time quantitative PCR. The results showed that the 42 ℃ stress, ABA and mannitol treatment significantly increased the expression level of DcHsfA4. Moreover, the expression pattern of DcHsfA4 was different at 4 ℃ stress. The transcripts of DcHsfA4 were up-regulated by drought treatment for 24 h and NaCl treatment for 12 h. The results provide a basis for further exploration of the characteristics of carnation heat shock transcription factors and the biological functions in response to stress.
