Isolation and Screening of cry and parasporin Genes of Native Bacillus thuringiensis from Cherry Gardens in Izmir

Bacillus thuringiensis (Bt), which produces various proteins, is a versatile microorganism. In this study, we performed Bt isolation from cherry orchards in İzmir (Türkiye) and characterization of cry and parasporin (ps) genes related to the proteins that are insecticidal and cytotoxic, respectively. Forty-one soil samples were collected, and 314 Bt-like colonies were obtained from these samples. According to phase contrast microscopy examination, 80 colonies showing crystal formation were identified as ‘Bt’. Polymerase chain reaction (PCR) was performed to determine the cry and ps gene profiles of the isolates. It was found that 66 out of the 80 samples carried cry1, cry2, or cry3 genes. The most common of these genes was the cry1 (68%). In the case of parasporin gene screening, the existence of ps1, ps2, ps3, ps4, ps5, and ps6 genes was investigated. Seventeen of the 80 isolates were found positive for ps genes. Among these, the ps6 gene showed the highest frequency with 29%, followed by the ps3 gene (24%). Partial DNA sequence analysis of seven ps-positive isolates showed that 5.4, 5.7, 5.10, 7.1, and 7.3 showed 99% identity with ps6, and the other isolates 2.1 and 40.4, matched with 98% and 97% identity with ps1 and ps2, respectively. In conclusion, this study reports a new Bt collection from Türkiye. The native Bt isolates carrying cry and/or ps genes will help us select potential ones with insecticidal and cytotoxic effects that will form the basis for the production of recombinant parasporal proteins planned in future studies.