Abstract:

A gene named MdDRB1 cloned from Malus × domestica‘Royal Gala’was analyzed. To understand sequence characteristics of the gene，prokaryotic expression and subcellular localization were carried out. In addition，real-time quantitative PCR were performed to determine the expression levels of MdDRB1 in response to various abiotic stresses. Finally，MdDRB1 was genetically transformed into apple seedlings to identify its function. The analysis of gene structure revealed that there were two introns and three exons in genomic sequence of MdDRB1. Subcellular localization showed that MdDRB1 were mainly distributed in the nucleus，a small number distributed in the cytoplasm. Then，the induced protein showed that MdDRB1 fusion protein existed in the form of inclusion body. Furthermore，the miRNA related to resistance expression level raised in antisense transgenic apple callus. In addition，real-time quantitative PCR found that the MdDRB1 gene expression level significantly raised after treated with PEG，NaCl，ABA and 4 ℃. Overexpression of MdDRB1 remarkably increased the tolerance of transgenic apple seedlings to abiotic stresses. These results indicated that MdDRB1 might be involved in the response of apple to abiotic stresses.

Key words: apple, MdDRB1, prokaryotic expression, subcellular localization, stress esponse