Cloning of chitinase gene from <i style="">Bacillus thuringiensis</i>

Abstract

In the present investigation, 34 <i>Bacillus thuringiensis</i> (<i style="">Bt</i>) isolates of different agroclimatic condition were studied for fungitoxic characters and the principle involved for fungitoxicity was identified in most of the cases as exochitinases. The different <i style="">Bt </i>strains were screened for fungitoxicity and chitin degrading activity employing 4 fungal pathogens. Biochemical assay of the chitinase using glycol chitin as the substrate helped to identify the enzyme as an exochitinase. The antifungal chitinase activity on phyto-pathogenic <i>Fusarium oxysporum </i>f. sp. <i>cubense </i>was investigated <i>in vitro </i>by fluorescent microscopic observation. PCR was employed using chitinase gene specific primers to obtain the corresponding gene from <i style="">Bt</i> isolates. The corresponding gene was cloned and sequenced for one of the isolates and it was determined to be around 1129 bp, encoding a polypeptide of 360 amino acids. This gene was found to be highly homologous to that of chitinase of <i style="">B. cereus </i>strain 28-9.