A new mutation in the pufL gene responsible for the terbutryn resistance phenotype in Rubrivivax gelatinosus.
Rubrivivax gelatinosus is a facultative phototrophic non-sulfur bacterium belonging to the beta subclass of the purple bacteria. A terbutryn-resistant mutant of R. gelatinosus has been isolated and characterized. Increased resistance levels to terbutryn (300-fold), atrazine (6-fold) and o-phenanthroline (3-fold) were observed for the mutant compared with wild type. Sequence analysis of the mutant revealed a new mutation in the pufL gene coding for the L subunit of the reaction centre (RC) at codon 192 leading to an amino-acid substitution from Gly in the wild type to Asp in the mutant. This substitution is located in the D helix of the L subunit, suggesting an interaction between terbutryn and this part of the polypeptide in the RC of R. gelatinosus. This is the first report of a mutation leading to herbicide resistance and affecting the D helix in purple bacteria. Furthermore R. gelatinosus wild type is highly sensitive to o-phenanthroline compared with other purple bacteria (Rhodobacter capsulatus and Rhodobacter sphaeroides). Sequence comparison of the L subunit from six purple bacteria in which o-phenanthroline sensitivity was measured suggests that SerL226 might be responsible for this phenotype.
Ouchane
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CNRS, Centre de Génétique Moléculaire, Gif-sur-Yvette, France.
Picaud
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Astier
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D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D001483:Base Sequence; D017931:DNA Primers; D004269:DNA, Bacterial; D004352:Drug Resistance, Microbial / Q000235:genetics; D005798:Genes, Bacterial; D045342:Light-Harvesting Protein Complexes; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics*; D012244:Rhodospirillaceae / Q000187:drug effects / Q000235:genetics*; D014227:Triazines / Q000494:pharmacology*
D001426:Bacterial Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; C096433:PufL protein, Bacteria; D014227:Triazines; C010347:terbutryne