Molecular Screening and Bioactivity of Native Bacillus thuringiensis Isolates

Bacillus thuringiensis strains were isolated from various soil samples collected from different regions of Kahramanmaraş in Turkey and were characterized by their colony morphology, PCR method with cryIAb/Ac, cryID, cry۲ and cyt۲ primers, and SDS-PAGE of crystal proteins with ۱۳۰-۱۴۰ and ۶۰-۷۰ kDa molecular weights. Plasmid profiles of selected isolates were also analyzed. Among the cry genes studied, cry۱Ab/Ac was found to be the most common one (۶۰%) in local isolates. Bioactivity tests were carried out under laboratory conditions to assess the efficacy of isolates against the third instar larvae of the stored product insects; Anagasta kuehniella and Plodia interpunctella. Toxicity values of the isolates varied between ۲۰.۰۰-۵۳.۳۳% for A. kuehniella and ۲۰.۰۰-۵۵.۵۶% for P. interpunctella at ۱,۰۰۰ µg g-۱ concentration. Out of ۵۵ isolates, ST۱۳.۱ was found to be the most effective against A. kuehniella. Also, ST۷.۲, ST۷.۳, and ST۸.۲ isolates yielded remarkable control against P. interpunctella. Further research is recommended to investigate the efficacy of these promising Bt isolates against other pest insect species.

کلیدواژه ها:

Bacillus thuringiensis ، Bioactivity ، Cry gene ، Stored product insects ، toxicity