Title A Highly Pathogenic Strain of Bacillus thuringiensis serovar kurstaki in Lepidopteran Pests
Author Hatice Kati1*, Kazim Sezen2, Remziye Nalcacioglu2, and Zihni Demirbag2
Address 1Department of Biology, Faculty of Arts and Sciences, Giresun University, Giresun 28049, Turkey, 2Department of Biology, Faculty of Arts and Sciences, Karadeniz Technical University, Trabzon 61080, Turkey
Bibliography Journal of Microbiology, 45(6),553-557, 2007,
DOI
Key Words Bacillus thuringiensis, Balaninus nucum, cry gene, Lymantria dispar, Malacosoma neustria
Abstract In order to detect and identify the most toxic Bacillus thuringiensis strains against pests, we isolated a B. thuringiensis strain (Bn1) from Balaninus nucum (Coleoptera: Curculionidae), the most damaging hazelnut pest. Bn1 was characterized via morphological, biochemical, and molecular techniques. The isolate was serotyped, and the results showed that Bn1 was the B. thuringiensis serovar, kurstaki (H3abc). The scanning electron microscopy indicated that Bn1 has crystals with cubic and bipyramidal shapes. The Polymerase Chain Reactions (PCRs) revealed the presence of the cry1 and cry2 genes. The presence of Cry1 and Cry2 proteins in the Bn1 isolate was confirmed via SDS-PAGE, at approximately 130 kDa and 65 kDa, respectively. The bioassays conducted to determine the insecticidal activity of the Bn1 isolate were conducted with four distinct insects, using spore-crystal mixtures. We noted that Bn1 has higher toxicity as compared with the standard B. thuringiensis subsp. kurstaki (HD-1). The highest observed mortality was 90% against Malacosoma neustria and Lymantria dispar larvae. Our results show that the B. thuringiensis isolate (Bn1) may prove valuable as a significant microbial control agent against lepidopteran pests.
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