ISOLATION AND CHARACTERIZATION OF NATIVE ISOLATES OF BACILLUS THURINGIENSIS (BERLINER) STRAINS FROM DIFFERENT ECOLOGICAL HABITAT IN INDIA.

Bacillus turingiensis (Berliner) is a Gram positive, rod shaped and spore forming bacterium, which produces crystal proteins (proteinaceous inclusions), called δ-endotoxins, that have insecticidal action. The present investigation was carried out to isolate B. thuringiensis from soil, leaf, compost, leaf litter, diseased larvae and rhizosphere samples collected from the various locations in the states of Uttarakhand, Himachal Pradesh, Kerala, Karnataka and Maharashtra. A total of 300 samples were collected and isolation of the B. thuringiensis strains was carried out. The presence of crystalline inclusions in Bacilli like colonies was observed in 49 samples collected from the state of Uttarakhand, eight samples from Himachal Pradesh, six samples from Kerala, four samples from Karnataka and three samples from Maharashtra. Totally, 70 isolates showed milky white colonies with circular shape and colonies produced serrated margin similar to that of the reference strain HD1. Gram staining revealed that all the 70 isolates were rod-shaped, gram-positive bacteria, which were appeared to be blue or violet in colour under the Phase contrast microscope. Among the 70 isolates, 67 (97.74%) isolates showed bipyramidal type of crystal and the remaining three isolates such as, Bt-21, Bt-37 and Bt-278 showed square, elliptical and spherical crystal shape, respectively. The present study has established the diversity and richness of B. thuringiensis like isolates in soil and leaf samples collected from five selected states of India. [ABSTRACT FROM AUTHOR]