Abstract：Dehydration responsive element binding protein (DREB) belongs to the APETALA2/ethylene response factor (AP2/ERF) family in plants, which is a large group of plant-specific transcription factors. The DREBs widely participate in various abiotic stresses, such as drought, salt, heat, and cold. In order to explore the function of DREB in Malus zumi, a new gene named MzDREB2A (GenBank No. MH992511) was isolated and cloned using the method of rapid amplification of cDNA ends (RACE). The open reading frame of MzDREB2 was 1 197 bp without intron structure, encoding 398 amino acids and containing an AP2 domain with the molecular weight 43.9 kD and the isoelectric point 4.93. Bioinformatic analysis showed that MzDREB2A was a hydrophilic protein and had no transmembrane region, and the secondary structure contained 7.54% α-helix, 4.52% β-sheet, and 87.94% random coils. Homology analysis and phylogenetic analysis showed that MzDREB2A protein had the highest sequence similarity (about 99%) and closest genetic relationship to Malus sieversii. qRT-PCR analysis showed that MzDREB2A exhibited the highest expression level in roots followed by blades, and the lowest expression level in stems. The expression level of MzDREB2A sharply increased under NaCl or PEG-6000 treatment, and MzDREB2A expression reached the maximum when NaCl concentration was 150 mmol/L and PEG-6000 concentration was 20%, respectively. This study successfully cloned the MzDREB2A of AP2/ERF family in Malus zumi, which might provide a reference for further study on the function of MzDREB2A and the molecular mechanism of stress resistance in Malus zumi.
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