STUDY OF THE DELTA-ENDOTOXINS PRODUCED BY 3 RECENTLY ISOLATED STRAINSOF BACILLUS-THURINGIENSIS

Three different strains of Bacillus thuringiensis, subsp. toumanoffi, sotto and kurstaki, producing parasporal inclusion crystals, have rece ntly been isolated in Tunisia. The delta-endotoxins produced by the di fferent strains gave distinct patterns on sodium dodecyl sulfate-polya crylamide gel electrophoresis. Polymerase chain reaction screening of these three strains, using oligonucleotides specific for the genes cry IA, cryIII and cryIV, did not generate amplified fragment profiles cha racteristic of these genes. For each of the strains, the presence of o ne or more delta-endotoxin coding genes having partial sequence simila rities to one or more genes of these three groups was found.