ISOLATION AND CHARACTERIZATION OF BACILLUS THURINGIENSIS STRAINS CONTAINING CRYI GENES FROM SOIL SAMPLES OF NEPALPAWAN PARAJULI, NEESHA RANA, SANGITA SHRESTHA, JYOTI MAHARJAN, PRABINA RANA AND JAISHRI SIJAPATIAbstract Bacillus thuringiensis (Bt) based pesticides have become one of the most widely used microbial pesticides. The identification of cry gene variant in Bacillus thuringiensis isolates can be useful in predicting the insecticidal activity of a given strain. Twelve Bacillus thuringiensis isolates were isolated from soils of different geographic regions of Nepal. The characterization of the isolates were based on morphological characteristics of crystal and PCR analysis using seven pairs of primers specific for different cryI gene variant. Eleven Bt isolates out of twelve strains showed the presence of at least one of the cryI gene. The cryIA(c) gene was the most abundant cryI-type gene representing 91.6% of the native Bt isolates. One of the native isolate Bag2C showed the presence of all the cryI –type genes (cryIA, cryIB, cryIC and cryID). Therefore Bag2C can be a promising isolate for developing biological control agent against lepidopteron pests.
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