[Cloning and expression of trehalose synthase genes in Escherchia coli]

Escherichia coli trehalose synthase otsBA genes have been cloned by using transposon Mu in vivo. The cloning frequency was 1.45 x 10(-3)/Kanr transductant. Genetic complements, endonuclase digestion and partial nucleotide sequencing analysis of these clones indicated that otsBA gene was on plasmid Mud5005. Subcloning 2.87 kb DNA fragment onto expression plasmids with higher or lower copy number and transforming into E. coli recipient strain FF4050, which have otsBA genes deleted respectively, the transformed strains obtained ability of growth on medium containing 0.5 mol/L NaCl and increased trehalose synthesis under high osmotic pressure. Production and accumulation of trehalose may play an important role in crop breeding. These studies will lay an important foundation for constructing an expression vector with the otsBA genes and transformation to tobacco mediated by Agrobacterium, and obtaining ability for drought resistance and high osmotic pressure tolerance.