Molecular Characterization and Overexpression of Erwinia chrysanthemi Strain CSCL006 hrpNCSCL006 Gene, which Encodes An Elicitor of the Hyperdensitive Reaction
TANG Cheng;CUI Ya-ya;WU Bo-ji ;LI Ming-yang
1.Horticulture and Landscape College, Southwest University, Chongqing 400715, China; 2. Life Science and Technology College, Southwest University for Nationalities , Chengdu 610041, China; 3. Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
Abstract：The DNA library of Erwinia chrysanthemi isolation CSCL006 was constructed. The hrpNCSCL006 gene was cloned from the DNA library and the nucleotide sequence was determined. The nucleotide sequence of hrpNCSCL006 revealed a coding region of 1 020 bp which matched well with the size of hrpNCSCL006 transcript determined by Northern blot. Alignment of the deduced amino acid sequence of harpin CSCL006 with harpin sequences of other soft-rot Erwinia species in database demonstrated that harpin CSCL006 shares high homology with harpins of Erwinia chrysanthemi strains EC16 and 3937, but relatively lower homology with harpins of Erwinia carotovora subspcorotovora. hrpNCSCL006 was cloned into a expression vector pET28a(+) and overexpressed in Escherichia coli. The ca. 34 kD overexpressed polypeptide matched well with the size of predicted harpinCSCL006. Using anti-harpinEcc antibodies as probe, Western blotting analysis confirmed that the overexpressed protein was harpinCSCL006. The harpinCSCL006 fractionated from E. coli could elicite the hypersensative reaction in tobacco (Nicotiana tabacum) leaves.
