Cloning, expression and antifungal effect of the recombinant chitinase from Streptomyces sampsonii KJ40

ABSTRACT: Streptomyces sampsonii is a kind of biocontrol bacterium with antifungal effects, and chitinase is one of the main antifungal substances. To improve and further study the structure and function of the chitinase gene of S. sampsonii, we amplified the target fragment by PCR, ligated the fragment to the expression vector pET-32a, introduced the resulting plasmid into Escherichia coli BL21 (DE3) and induced expression of the chitinase. Then, the recombinant chitinase was purified by is-labelled protein micro purification kit. A chitinase gene, Sschi61, was cloned from the genome and expressed in a prokaryote. The antifungal effect of the recombinant protein was also studied. Finally, the chitinase gene Sschi61 with a length of 1755 bp was obtained, and the expression of the 82 kDa recombinant chitinase was induced in E. coli by IPTG. The recombinant chitinase could inhibit the black spot pathogen of Eucommia ulmoides (Pestalotiopsis trachicarpicola). After the hyphae of the pathogen of black spot of Eucommia ulmoides (Pestalotiopsis trachicarpicola) were soaked with recombinant chitinase, the hyphae cells expanded, broke, and dissolved.