Phage abortive infection of Bacillus licheniformis ATCC 9800; identification of the abiBL11 gene and localisation and sequencing of its promoter region

The virulent bacteriophage BL11 infects almost all Bacillus licheniformis s trains tested, including the industrial bacitracin-producing B. licheniform is 19. B. licheniformis ATCC 9800, however, was virtually insensitive to ph age BL11 infection, and all of the few surviving progeny phages proved to b e mutants. The phage-resistance mechanism was neither inhibition of adsorpt ion, nor restriction or exclusion provided by a resident prophage, but was, instead, of another type. Phage BL11 adsorbed well on to ATCC 9800 cells, its DNA was injected, but replication of phage DNA was inhibited and the in fected cells died. Thus, the mechanism of phage resistance was identified a s abortive infection (AbiBL 11). The so-called abiBL11 gene was identified on the chromosome of strain ATCC 9800 by Tn917PF1 transposon mutagenesis. P art of the abiBL11 gene from the phage-sensitive ATCC 9800::Tn917PFI was cl oned. Gene-disruption analysis, based on Campbell-type integration, showed that a 0.3-kb EcoRI fragment contained the 5' end of abiBL11. The promoter region of abiBL11 was identified using promoter- and terminator-probe plasm ids. The deduced sequence (206 amino acids) of the N-terminal part of abiBL 11 showed no significant homology to known abortive-infection genes, but di d show homology to a Saccharomyces cerevisiae gene coding for a serine/thre onine protein kinase (RCK1).