Diversity of isolates from Egyptian soils as shown by molecular characterization.

Different techniques were adopted for molecular characterization of several indigenous strains of () previously isolated from Egyptian soil samples. These isolates show different toxicity levels against neonate larvae of both insect species; (Biosduval); and (Hübner). The parasporal crystals among the most potent isolates contained polypeptides of about 127 and 130 kDa. PCR screening for genes encoding different genes was performed. The 1 gene is the most abundant in these isolates (83.33%) among tested -type genes, followed by 1 gene subfamilies ( 1B and 1C) with percentage of 38.88% and 77.77%, respectively. The tested isolates showed the presence of 2A(a,b) gene, but not all of these isolates were positive for 2 gene (55.55%). Only 27.77% and 16.66% of the tested isolates harbor 4 and 3 genes, respectively. All strains were negative in PCR assays for the 3Aa1 gene. Moreover, DNA fingerprinting using RAPD-PCR was performed to detect the genetic similarities and dissimilarities among the different isolates and standard strains. Assessment of diversity based on the combined analysis of their protein and RAPD-PCR banding patterns was performed. This study demonstrates that strains isolated from Egyptian soil samples can be distinguished and identified on the basis of the distribution of -type genes and RAPD fingerprints.