GENOMIC ORGANIZATION OF THE ENTOMOPATHOGENIC BACTERIUM BACILLUS-THURINGIENSIS SUBSP BERLINER 1715

A physical and genetic map of the Bacillus thuringiensis subsp, berlin er 1715 (serotype 1) chromosome was constructed by pulsed field gel el ectrophoresis using three restriction enzymes, Asci, Notl and Sfil. A total of 24 restriction enzyme sites and 28 probes were located on the map. The chromosome size was 5.7 Mb. Consistent with previous mapping of Bacillus cereus chromosomes, the genes were nonrandomly distribute d. Genes which are often plasmid-encoded were located on one half of t he chromosome, whereas the other half contained rRNA genes and the ori gin region. Hybridization with macro-restriction fragments showed that the region containing rRNA genes and the origin was similar to that o f the B. cereus type strain, ATCC 14579, and confirmed that the region was conserved between the B. cereus and B. thuringiensis chromosomes. The insecticidal toxin probe crylA or the transposon probe Tn4430 hyb ridized to six extrachromosomal elements of 60, 60, 100, 130, 270 and 600 kb, indicating that the genome size was at least 6.9 Mb.