IncN plasmids mediate UV resistance and error-prone repair in Pseudomonas aeruginosa PAO.
While it seems likely that the ability to induce the expression of recA-controlled genes is nearly universal among the eubacteria, the expression of plasmid-borne ultraviolet (UV-resistance and mutagenesis genes seems to be species-dependent in a complex fashion. Some plasmids encoding UV-resistance and mutagenesis functions only express these phenotypes in a select number of bacterial species. Several UV-resistance plasmids that express these functions in Escherichia coli are either unstable or simply do not express the UV-resistance-mutagenesis phenotype in Pseudomonas aeruginosa. In order to clarify the role of these plasmids in microbial ecology, we have undertaken a study of the ability of the well-characterized UV-resistance IncN plasmids pKM101 and R46 to express the UV-resistance phenotype in P. aeruginosa. In addition, we have examined the IncP plasmids RP4 and R68.45, observed to confer a UV-resistant phenotype upon Myxococcus xanthus, for the ability to express this phenotype in P. aeruginosa. Our experiments reveal that while pKM101 and R46 transfer to P. aeruginosa at a very low frequency, these plasmids, once transferred, are maintained and clearly support the expression of the UV-resistance and mutagenesis phenotype observed in E. coli. Studies of plasmids R68.45 and RP4 in P. aeruginosa revealed that they do not express UV-resistance functions in this species. UV-resistance plasmids may play an important role in the natural ecology of bacterial habitats exposed to solar radiation or to various DNA-damaging natural and man-made chemicals.
Kokjohn
T A
TA
School of Biological Sciences, University of Nebraska-Lincoln 68588-0118.
Miller
R V
RV
D004260:DNA Repair / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D016296:Mutagenesis; D010641:Phenotype; D010957:Plasmids / Q000235:genetics*; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D011836:Radiation Tolerance / Q000235:genetics; D014466:Ultraviolet Rays