摘要：AbstractThe present study was conducted to isolateBacillus thuringiensis(B.t.) strains from different ecological regions of Pakistan and determined the mosquitocidal activity ofcry4Acrystal protein gene against the dipteran insects. Out of 25B.t. isolates, 5 isolates were selected on the basis of toxicity and 4 were identified asBacillus thuringiensisGCU-DAB-TK-04 (MN922746), GCU-DAB-TK-06 (MT032397), GCU-DAB-TK-09 (MN922747), and GCU-DAB-TK-13 (MT032398). GCU-DAB-TK-04 was found to be the most toxic strain against the 3rd instar larvae ofAedes aegypti. The presence of Cry 4A protein was confirmed by the amplification ofcry4Agene (accession number MT001910) from GCU-DAB-TK-04. The highest spores toxicity was shown by GCU-DAB-TK-04 (LC50 = 104 μg/ml) while LC50values of other strains were GCU-DAB-TK-13 (LC50 = 602 ± 0.43 μg/ml) GCU-DAB-TK-06 (LC50 = 812 ± 0.63 μg/ml), GCU-DAB-TK-12 (LC50 = 1230 ± 1.14 μg/ml), and GCU-DAB-TK-09 (LC50 = 7585 ± 1.17 μg/ml). Similarly, the highest toxicity of total cell protein was also shown by GCU-DAB-TK-04 (LC50=676 ± 0.53 μg/ml while LC50values of other strains were GCU-DAB-TK-13 (LC50 = 724 ± 1.12 μg/ml), GCU-DAB-TK-06 (LC50 = 741 ± 0.64 μg/ml), GCU-DAB-TK-12 (LC50 = 912 ± 0.65 μg/ml), and GCU-DAB-TK-09 (LC50 = 1621 ± 1.13 μg/ml). The order of toxicity ofB.t. strains was GCU-DAB-TK-04 > GCU-DAB-TK-13 > GCU-DAB-TK-06 > GCU-DAB-TK-12 > GCU-DAB-TK-09.Protein analysis showed that 130 kDa (probably Cry4A, B), 70 kDa (Cry4C, D) and 20 kDa (Cyt enhancer protein of Cry4) proteins were present in allB.t. strains. TheseB.t. strains have found great potential to grow into bio-insecticidal formulation for the eco-friendly control of mosquitoes.
关键词：KeywordsB.t. strainsCry4AgeneCry 4A proteinBiotoxicityAedes aegypti
