Abstract:

A 6-phosphoglueonate dehydrogenase gene named Md6PGDH1（MDP0000279299）was cloned from‘Royal Gala’apple（Malus × domestica Borkh.）. Sequence analysis indicated that the length of Md6PGDH1 gene was 1 047 bp，which encoded 347 amino acids. It was predicted that the molecular mass of this protein was 36.430 kD，and pI was 9.24. Homology analysis showed that there were three other homologous genes；Analysis of functional domain showed that the Md6PGDHs protein included two conserved binding domains；the prediction of subcellular localization showed that there were differences in Md6PGDHs protein. In silico analysis suggested that the promoter sequence contained several cis-acting elements，including abiotic stresses responsive elements and hormone responsive elements. qRT-PCRs were performed to determine the expression levels of apple Md6PGDH1 in different tissues and in  response to abiotic stresses. Prokaryotic expression and activity assay of the Md6PGDH1，which laid a foundation for protein function identification. Overexpression of Md6PGDH1 in apple callus increased the tolerance of transgenic apple callus to high salinity.

Key words: Malus × domestica, Md6PGDH, expression analysis, Md6PGDH1, prokaryotic expression, callus