Journal of Pure and Applied MicrobiologyVol. 6 No. 4

Characterization of Bacillus thuringiensis Isolates from Soils of Rice Ecosystem in UKP Area, Karnataka, India

Basavaraj Kalmath*, Venkateshalu, Sushila Nadagouda, Shreedevi Jukthihiremath1 and B.C. Meenakshi2

Department of Entomology, College of Agriculture Bheemarayanagudi, University of Agriculture Sciences, Raichur - 560 065, India. 1Department of Bioinformatics, KSWU, Bijapur, 2Department of Agriculture Microbiology, UAS, Bangalore, India.

Received on 30 April 2012 and accepted on 08 June 2012

 

ABSTRACT

An investigation was conducted to study the diversity of entomopathogenic bacteria Bacillus thuringiensis, in rice ecosystem in UKP area Karnataka, India. Survey was conducted to collect soils from different places and Bacillus thuringiensis were isolated. Totally 72 B. thuringiensis isolates were collected from the survey. The cell sizes of the B.thuringiensis isolates varies from 1.45x0.83 Ám to 3.49x0.63 Ám, where as endospore size varies from 0.83-0.66 Ám to 1.66-0.66 Ám. Among collected bacteria 64 % of the isolates produced bipyramidal crystal shape and 3 % produced triangular shape, 9 % produced bipyramidal and triangular shape, 9% produced spherical, 2 % produced ovoid and 2% produced triangular and bipyramidal shape. The pathogenicity of isolates against 2 nd instars Diamond back moth larvae showed, mortality ranged from 0 to 100 per cent. Bioassay showed that LC50 value was minimum in Thanegundi isolate (1.9x10-4) followed by Karkalli, Yevur and Gogi isolates.

Keywords : Bacillus thuringensis, Bioassay, Crystal protein staining and Rice ecosystem.