关键词: 苹果, MdMYB2, 基因克隆, 盐胁迫

Abstract: MdMYB2 gene was cloned from Malus × domestica‘Gala’with homologous cloning using RT-PCR method. Its open reading frame（ORF）contained 873 bp nucleotides，which encodes a predicted protein containing 290 amino acid residues. The predicted protein has a molecular mass of 32.92 kD and a pI value of 4.91. Phylogenetic analysis demonstrated that MdMYB2 showed the highest evolutionary relationship with PbMYBL2 from pear. Expression analysis showed that the MdMYB2 gene was constitutively expressed in different tissues，with rather higher expression levels in fruit and stem than in others. Meanwhile，its expression was noticeably induced by salt stress treatment. Finally，transgenic apple calli and Arabidopsis were obtained with Agrobacterium-mediated genetic transformation. Tolerance assays indicated that overexpression of MdMYB2 remarkably enhanced the tolerance of transgenic apple calli to high salinity，further supporting that MdMYB2 positively regulates salt tolerance in apple. In addition，ectopic expression of MdMYB2 also enhanced salt stress tolerance in Arabidopsis，indicating that MdMYB2 plays an important role in plant salt stress tolerance.

Key words: apple, MdMYB2, gene clone, salt stress