A NEW PCR-BASED APPROACH TO A FAST SEARCH OF A WIDE SPECTRUM OF CRY GENES FROM BACILLUS-THURINGIENSIS STRAINS

A pair of highly degenerated primers was adapted to carry out a single -step PCR-detection of any known and probably unknown cry genes of cla sses cry1, cry4 and cry9 encoding for 130 kDa protein delta-endotoxins in the natural Bacillus thuringiensis (BT) strains. The Southern hybr idization of the product has demonstrated that essentially remote cry- genes like cry1Aa and cry9A (cryIG) could be represented in the single amplificate if they are simultaneously present in the genome of the a nalyzed strain. Four genes were detected by the proposed scheme in the BT ssp. galleriae 11-67. One of them, gene cry1Ga1 was originally fou nd and cloned using the PCR-amplification product obtained from the ge nomic DNA of this strain as a probe. The new gene was completely ident ical to one cloned by B. Lambert (unpublished, EMBL accession number Z 22510) and essentially related to cryIM (EMBL accession number Y09326) , renamed according to the new nomenclature as cry1Ga2.