IDENTIFICATION AND MOLECULAR GENETIC CHARACTERIZATION OF SOMEBACILLUS THURINGIENSIS EGYPTIAN ISOLATES

Abstract

The discovery of a highly toxic isolates reveals the usefulness of screening studies for novelBt strains.Bacterial samples were isolated from soil of sixteen Egyptian governorates.Different treatments were followed to select spore-forming bacteria from global bacterial flora.Bacillus thuringiensiswas selected according to colony morphology (round, about 3-5 mm in diameter, raised or flat slightly shiny, grayish white opaque with entire edge and having a granular surface.The microscopic examination showed that the Bacillus isolates are Gram-positive rod shaped bacteria.SDS-PAGE analysis detected 3 bands with MWs at 130, 65 and 35 KDa. All Bacillus strains exert a percentage of mortality comparing to the control (0%), strains number 9 and 15 showed appreciable mortality of 100% and 96.6%, respectively. Strain number 9 amplified a single fragment of about 490 bp belong to cryIgene family using PCR analysis.Electron microscope for crystal protein morphologyinstrainnumber 9 produced bipyramidal crystal proteins, consistent with the presence of Cry1 protein, strain number 14 from sharkia produced spherical shaped crystals.16S rRNA gene from strains number 9 and 15 was sequenced.Resultsshowed 99% and98%of identity with the sequence from Bacillus thuringiensisBt 407 andATCC 10792, respectively, on database. Key words:B. thuringiensis, crystal proteins, 16SrRNA,cryI, cryIII and cryIV.