Distribution of icry/iand icyt/iGenes among Indigenous iBacillus thuringiensis/iIsolates with Mosquitocidal Activity

摘要

Bacillus thuringiensis strains isolated from Madurai, TamilNadu, India were evaluated for their mosquitocidal activity, as well as cry and cyt genes diversity. It revealed that 99% of the parasporal crystal morphology of these isolates was spherical in nature and a variable percentage (0% - 100%) of toxicity was observed against Culex quinquefasciatus and Aedes aegypti. PCR analysis revealed that 53% of the isolates were positive for the various cry and cyt genes tested, whereas 47% did not produce any PCR product for the cry gene analyzed. Diverse pattern of cry and cyt genes distribution was observed even in the isolates from the same sample. B. thuringienis subsp. LDC-9 showed three-fold higher toxicity against Culex quinquefasciatus than that of B. thuringiensis var israelensis which might be used as a potential strain to control mosquitoes in near future after field evaluation.