Objective Involvement of DREB1B in the cold resistance of Fragaria mandschurica Staudt was studied.

Methods Full length cDNA of DREB1B in F. mandschurica was cloned by RT-PCR and analyzed bioinformatically. The sequence of FmDREB1B promoter was cloned with cis-acting elements predicted. GUS vector was constructed to be transiently transformed into tobacco leaves for staining and enzyme activity determination. Relative expression of FmDREB1B was analyzed using RT-qPCR.

Results The cDNA of FmDREB1B (GenBank accession number: MN738503.1) was 690 bp in length encoding 229 amino acids that included a conserved AP2 DNA-binding domain. The amino acids encoded by FmDREB1B had the highest homology with FvDREB1B. The FmDREB1B promoter (GenBank accession number: MN933919.1) contained several cis-acting elements associated with hormones and adversity stress responses. The transformation of pFmDREB1B::GUS into tobacco leaves resulted in the transcriptional activity of the promoter. DREB1B expressed in various tissues of F. mandschurica that peaked to be 22.58 times of 0 h after 6 h at 4 ℃. A 6 h ABA （Abscisic Acid）treatment produced a peak expression 15.28 times the original. In contrast, in F. ananassa Duch, the highest expression of DREB1B was 5.41-folds of that at 0 h under the same treatment at 4 ℃ for 6 h, while the ABA treatment resulted in merely 4.64-folds of 0 h.

Conclusion  The finding that DREB1B is involved in the low-temperature response, combined with its initial identification and functional characterization, lays a foundation for further research into its role in the cold tolerance mechanism of F. mandschurica.