Identification and characterization of phage‐resistance genes in temperate lactococcal bacteriophages

Abstract

Summary The sie2009 gene, which is situated between the genes encoding the repressor and integrase, on the lysogeny module of the temperate lactococcal bacteriophage Tuc2009, was shown to mediate a phage‐resistance phenotype in Lactococcus lactis against a number of bacteriophages. The Sie2009 protein is associated with the cell membrane and its expression leaves phage adsorption, transfection and plasmid transformation unaffected, but interferes with plasmid transduction, as well as phage replication. These observations indicate that this resistance is as a result of DNA injection blocking, thus representing a novel superinfection exclusion system. A polymerase chain reaction (PCR)‐based strategy was used to screen a number of lactococcal strains for the presence of other prophage‐encoded phage‐resistance systems. This screening resulted in the identification of two such systems, without homology to sie2009, which were shown to mediate a phage‐resistance phenotype similar to that conferred by sie2009. To our knowledge, this is the first description of a phage‐encoded superinfection exclusion/injection blocking mechanism in the genus Lactococcus.

The Dilemma of Phage Taxonomy Illustrated by Comparative Genomics of Sfi21-LikeSiphoviridaein Lactic Acid Bacteria

“…The sie gene is actually the most prominent transcript from the Sfi21 prophage (54). A sie function is not excluded for ORF 22 by the Clostridium link, since the predicted protein showed two membrane-spanning domains, which concurs with the data reported for the sie functions in lactococcal phages encoded at a corresponding genome position (44). ORF 19 without a database match is located between phage lysin and integrase genes.…”

Alterations in phage-typing patterns in vancomycin-intermediate Staphylococcus aureus

“…Phage infection can be prevented in Gram-positive bacteria as a result of adsorption inhibition (Chatterjee, 1969;Tran et al, 1999;Wilkinson & Holmes, 1979), restriction modification systems (Kong & Josephsen, 2002), DNA injectionblocking systems (McGrath et al, 2002), lysogenization (Beard-Pegler & Vickery, 1985) and abortive infection systems (Dai et al, 2001). We showed that the in vitro VISA investigated demonstrated minimal to no alteration in SmaI RFLPs compared with parent strains; however, alterations in phage types were common.…”

Lactic Acid Bacteria Resistance to Bacteriophage and Prevention Techniques to Lower Phage Contamination in Dairy Fermentation

“…It was speculated that the pNP40-encoded protein product might have an impact on the activity, production, or membrane insertion of Pip, thereby affect its biological function and prevent phage DNA entry [29]. The first description of a sie system of Lactococcus was published in 2002 and referred to the P335-type temperate lactococcal bacteriophage Tuc2009 [30]. After integration of the bacteriophage Tuc2009 genome into the lactococcal chromosome, the prophage protein Sie2009 is produced and blocks superinfecting phage DNA entry into the cell.…”

“…The effect of Sie2009 seems to be analogous to the effect of the lysogenic phage repressor (CI) preventing re-infection. In contrast, the presence of the sie2009 gene determines resistance to various phages, also to phages from other species [28,30]. Similarly to lactococci, in lactobacilli prophages are also a common phenomenon [31].…”

“…A superinfection exclusion system was also developed in Lactococcus lactis based on the sie2009 gene from the temperate phage Tuc2009 [30]. When cloned in trans, sie2009 provided resistance only to some 936-type phages used in the study.…”