Emergence of phenotypic variants upon mismatch repair disruption in Pseudomonas aeruginosa

SMANIA AM; SEGURA I; PEZZA R.J; BECERRA C; ALBESA I; ARGARAÑA CE

SOC GENERAL MICROBIOLOGY

Año: 2004 vol. 150 p. 1327 - 1327

utS is part of the bacterial mismatch repair system that corrects point mutations and small insertions/deletions that fail to be proof-read by DNA polymerase activity. In this work it is shown that the disruption of the P. aeruginosa mutS gene generates the emergence of diverse colony morphologies in contrast with its parental wild-type strain that displayed monomorphic colonies. Interestingly, two of the mutS morphotypes emerged at a high frequency and in a reproducible way and were selected for subsequent characterization. One of them displayed a nearly wild-type morphology while the other notably showed, compared with the wild-type strain, increased production of pyocyanin and pyoverdin, lower excretion of LasB protease and novel motilitycharacteristics, mainly related to swarming. Furthermore, it was reproducibly observed that, afterprolonged incubation in liquid culture, the pigmented variant consistently emerged from themutS wild-type-like variant displaying a reproducible event