Cloning, Sequencing and Characterization of 3-Hydroxybuty- rate Dehydrogenase Encoding Gene (bdh A) in Bradyrhizobium japonicum USDA110 Strain

摘要

The current study describes the molecular characterization of a clone which can restore the ability of bdhA mutant strains NGRPA2 and Rm11107 to utilize 3-hydroxybutyrate as a sole carbon source (Hbu~+ ). This clone was screened out by complementation experiment from Bradyrhizobium japonicum US-DA110 genomic library, and the presence of bdhA. gene in the clone was verified by Bdh assay and Southern blot analysis. Furthermore, the entire sequence of bdhA gene was sequenced and the sequence was deposited in GenBank database under the accession number AY077581. bdhA. gene comprises 789 base pairs and encodes Bdh with 262 amino acid of MW 27.59 kDa. Interposon ΩKm was inserted into the bdhA ORF at EcoR I site and the bdhA mutant was constructed in B. japonicum by homologous recombination. Plant assay result did not show obvious effects of mutation of bdhA gene on nodulation and nitrogen-fixation.