Cry gene profiling of PDKV Bacillus thuringiensis strains for specificity to Pectinophora gossypiella (Saunders)

Abstract

Bacillus thuringiensis (Bt) is a cosmopolitan, antagonistic soil bacterium widely recognized as an eco-friendly alternative to chemical insecticides in pest management. In the present study, ten PDKV Bt strains-SGd-1, SY-4, SA-6, SAk-6, SGn-5, SAk-9, SBn-2, SA-18, SGn-4, and SA-20—known for their toxicity against pink bollworm (Pectinophora gossypiella), along with the standard Btk HD-1 and Bacillus cereus strain were screened for the presence of insecticidal cry genes using four gene-specific primers: cry1, cry1Ac, cry2Ab, and cry9 specific to pink bollworm. PCR analysis revealed that the isolates harboured cry1, cry1Ac, and cry2Ab genes either individually or in combination, whereas the cry9 gene was absent in all strains. Among the screened isolates, cry1 was the most abundant, detected in 90.91% of the strains (HD-1, SA-6, SA-18, SA-20, SAk-6, SAk-9, SGd-1, SGn-4, SGn-5, SBn-2), followed by cry1Ac (54.55%) present in SA-6, SA-20, SAk-6, SAk-9, SGd-1, and SGn-5, and cry2Ab (45.45%) found in HD-1, SY-4, SAk-6, SGn-4, and SGn-5.