Summary: We examined the role of plasmid-based phage defence in maintaining plasmids, using colicin plasmids in Escherichia coli as a model system. Experimental data indicated that the possession of a colicin plasmid can confer limited protection against bacteriophages. A continuous culture model, using these experimental values, indicated that the observed limited protection alone could selectively maintain colicin plasmids, without requiring a competitive advantage due to colicinogeny. Phage defence might explain the current maintenance of colicin plasmids, given the naturally occurring high levels of resistance to colicins. This model also suggests that many plasmids might be maintained in natural populations, in part, by phage resistance, including ‘cryptic’ plasmids for which no phenotype is known.
BannisterD.,
GloverS.W.1968; Restriction and modification of bacteriophages and R+ strains of Escherichia coli K-12.. Biochem Biophys Res Commrn 30:735–738
CurtisM.D.,
JamesR.,
CoddingtonA.1989; An evolutionary relationship between the ColE5-099 and the ColE9-J plasmids revealed by nucleotide sequencing.. J Gen Microbiol 135:2783–2788
DunnyG.M.,
KrugD.A.,
PanC.,
LedfordR.A.1988; Identification of cell wall antigens associated with a large con- jugative plasmid encoding phage resistance and lactose fermentation ability in lactic streptococci.. Biochimie 70:443–450
GautierM.,
ChopinM.1987; Plasmid-determined systems for restriction and modification activity and abortive infection in Streptococcus cremoris.. Appl Environ Microbiol 53:923–927
LauP.C.K.,
ParsonsM.,
UchimuraT.1992; Molecular evolution of E colicin plasmids with emphasis on the endonuclease types.. In Bacteriocins, Microcins and Lantibiotics pp. 353–378JamesR.
Edited by Berlin & Heidelberg: Springer-Verlag.;
LevinB.R.1986; Restriction modification and the maintenance of genetic diversity in bacterial populations.. In Proceedings of the Conference of Evolutionary Processes and Theory pp. 669–688NevoE.,
KarlinS.
Edited by New York: Academic Press;
LevinB.R.,
LenskiR.E.1983; Coevolution in bacteria and their viruses and their plasmids.. In Coevolution pp. 99–127FutuymaD.,
SlatkinM.
Edited by Sunderland, MA: Sinauer Associates;
LevyS.B.1986; Ecology of antibiotic resistance plasmids.. In Antibiotic Resistance Genes: Ecology, Transfer, and Expression pp. 17–30LevyS.B.
Edited by Cold Spring Harbor, NY: Cold Spring Harbor Laboratory;
LinialM.,
MalamyM.H.1970; Studies with bacteriophage phill. Events following infection of male and female derivatives of Escherichia coli K-12.. J Virol 5:72–78
MurphyE.1989; Transposable elements in gram-positive bacteria.. In Mobile DNA pp. 269–288BergD.E.,
HoweM.M.
Edited by Washington, DC: American Society for Microbiology;
PugsleyA.P.,
OudegaB.1987; Methods for studying colicins and their plasmids.. In Plasmids, a Practical Approach pp. 105–161HardyK.G.
Edited by Oxford: IRL Press;
RileyM.A.,
GordonD.M.1992; A survey of Col plasmids in natural isolates of Escherichia coli and an investigation into the stability of Col-plasmid lineages.. J Gen Microbiol 138:1345–1532
RomeroD.A.,
KlaenhammerT.R.1990; Abortive phage infection and restriction/modification activities directed by pTR2030 determinants are enhanced by recombination with conjugal elements in lactococci.. J Gen Microbiol 136:1817–1824
SandersM.E.,
KlaenhammerT.R.1983; Characterization of phage-sensitive mutants from a phage-insensitive strain Streptococcus lactis-. evidence for a plasmid determinant that prevents phage adsorption.. Appl Environ Microbiol 42:944–950
SingW.D.,
KlaenhammerT.R.1990; Characteristics of phage abortion conferred in lactococci by the conjugal plasmid pTR2030.. J Gen Microbiol 136:1807–1815
SmitE.,
VenneD.,
vanElsasJ.D.1993; Mobilization of a recombinant IncQ plasmid between bacteria on agar and in soil via cotransfer or retrotransfer.. Appl Environ Microbiol 59:2257–2263