Abstract

MOLECULAR CHARACTERIZATION OF BACILLUS THURINGIENSIS FROM THE SOIL OF OOTY BOTANICAL GARDEN

Amit Sharma* and T. K. Dangar

Abstract

Bacteria, especially Bacillus thuringiensis (Bt) and B. sphaericus (Bs), are the most potent and successful group of organisms for effective control of insect pests and vectors of diseases. Bt is widely known and exploited for δ-endotoxin which is produced in a distinct proteinacious structure known as crystal or insecticidal crystal protein. Soil sample was collected from the fellow area of Ooty Botanical Garden. Different molecular studies were performed viz. SDS-PAGE electrophoresis for crystal proteins, amylase and catalase, agarose gel electrophoresis for plasmid and genomic DNA, UV absorption-temperature profile (Tm) and base (G+C)% composition of genomic DNA, determination of base (A+T)% composition and concentration of genomic DNA, determination renaturation rates (cot value) of genomic DNA to identify and characterize the isolate. Types of crystal proteins produced by the isolates were revealed by SDS-PAGE electrophoresis. The organisms were checked for their plasmid compositions and it has been found that all the organisms contained the megaplasmid of 29.6 kbp size. Both catalase and -amylase enzymes of the organisms produced more than 6 and 10 isozymes respectively which appeared all over the zymogram. However, the isozyme patterns of the organisms differed among themselves. The host spectrum of the isolates needs to be assessed at the native areas for their effective exploitation as biological control agents.

Keywords: Bt, Ooty Botanical Garden, host spectrum, soil, biological control agents.