Environmental Microbiology (2002) 4, 703-712

Keiichi Hosokawa, Nyun-Ho Park, Takashi Inaoka, Yoshifumi Itoh and Kozo Ochi (2002)
Streptomycin-resistant (rpsL) or rifampicin-resistant (rpoB) mutation in Pseudomonas putida KH146-2 confers enhanced tolerance to organic chemicals
Environmental Microbiology 4 (11), 703-712
Abstract: We found that certain Str-, Gen- or Rif- mutants derived from Pseudomonas putida KH146-2, which are resistant to streptomycin, gentamicin or rifampicin, respectively, are tolerant to the aromatic compound 4-hydroxybenzoate (4HBA). The minimum inhibitory concentration (MIC) of 4HBA as the sole carbon source for the wild-type strain was 1%, whereas the MIC for the mutants was 1.7%. Frequency of 4HBA-tolerant mutants among spontaneous Str-, Gen- and Rif- mutants was 5-15%, 3-5%, and 3% respectively. These 4HBA-tolerant mutants also tolerated to a variety of organic chemicals such as 3-hydroxybenzoate, aliphatic and heterocyclic compounds, chlorobenzoates, as well as organic solvents toluene and m-xylene. The Str mutants had a point mutation in the rpsL gene, which produces the ribosomal protein S12. The Rif mutants were found to have a point mutation in the rpoB gene, which encodes the RNA polymerase ß-subunit. Mutation points in Gen mutants still remain unknown. Str-, Gen- and Rif-phenotypes occurred in spontaneous 4HBA-tolerant mutants which had been selected by successively increasing concentrations (from 0.8% to 5%) of 4HBA. Complementation experiments with one of the Str mutants demonstrated a causal relationship between a rpsL mutation (str-1) and 4HBA tolerance. Uptake experiments using [¹⁴C]-4HBA revealed that apparent ability of 4HBA to be taken up by the membrane transport system was reduced two to threefold in the mutants compared to the wild-type strain, accounting at least partly for the enhanced tolerance to 4HBA. Our approaches thus could be effective in improvement of tolerance to aromatic compounds of bacteria applicable for bioremediation.
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Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
Pseudomonas putida (antagonist)