Sequence analysis of the chitinase gene cht1 of Bacillus circulans showed that it contained 2151 nucleotides,which codes the precursor of chitinase CHT1 with 717 amino acid residues.The nucleotide and deduced amino acid sequences of cht1 showed 81% and 95% homology with those of ChiA of B.circulans WL-12,respectively.The cht1 gene was cloned into the Escherichia coli-Bacillus subtilis shuttle vector pSUGV4 and two recombinant plasmids, named pUSCH1 and pUSCH2 which contained 2.9kb and 4.0 kb insert respectively,were obtained.The recombinant plasmids were transformed into B.subtilis DB104 and WB600.Chitinase activity was detected both in transformed E.coli and B.subtilis.The DB104/pUSCH1 strain was found to be effective in the bio-controlling the infection of Magnaporthe grisea under greenhouse condition,which showed 71.67% decrease in rice disease incidence.
