Biochemical and molecular characterization of delta-endotoxins in Bacillus thuringiensis native strain

VIDAL DOMÍNGUEZ ME; SALERNO, GL; BERÓN, CM

Trabzon-Turkey

Congreso; 43th Annual Meeting of the Society for Invertebrate Pathology, 10th International Colloquium on Invertebrate Pathology and Microbial Control; 2010

Society for Invertebrate Pathology

Agriculture is one of the bases of Argentina´s economy. Some lepidopteran and coleopteran species cause significant damage to many agricultural important crops. Anticarsia gemmatalis, Spodoptera frugiperda, Diabrotica speciosa and Anthonomus grandis are currently endangering large areas of soybean, wheat, corn, rice, cotton and forage grasses. We described a Bacillus thuringiensis strain (FCC7) isolated from a soil sample in Argentina. This strain was shown to be toxic against larvae of lepidopterans (Anticarsia gemmatalis and Spodoptera frugiperda) and coleopterans (Diabrotica speciosa, Tenebrio molitor and Anthonomus grandis). It has a rounded crystal protein inclusion and its SDS-PAGE polypeptide pattern showed the presence of two major bands of 50 and 135 kDa. Through an approach based on PCR amplification of DNA fragments with degenerated oligonucleotides, we could retrieve partial cry homologous sequences, and a TAIL-PCR methodology allowed us to obtain a full length cry sequence, after confirmed by primer walking. BLASTp analysis using the deduced amino-acid sequence indicated that this novel sequence is related to proteins of the Cry8Aa type. In order to obtain other coding sequences from FCC7 strain, we used a PCR-DGGE based approach.We found two partial sequences homologous to cry1I genes. These results indicate that a combination of at least two Cry proteins may be responsible for FCC7 toxicity.