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Recombination deficient mutants of Rhizobium meliloti 41
Molecular & General Genetics : MGG
|January 1, 1983
Abstract:
Two mutants deficient in homologous genetic recombination have been isolated from Rhizobium meliloti 41 after Tn5 mutagenesis. Both mutants are defective in the induction of temperate phage 16-3 by UV-light, Mytomycin-C or Bleomycin, their UV sensitivity is more pronounced than that of the wild-type strain, and they lack the 'SOS activity' responsible for induced mutations.
Insights
Two Rhizobium meliloti mutants lacking homologous recombination were identified. These mutants show increased UV sensitivity and defects in phage induction and SOS activity.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Homologous genetic recombination is crucial for DNA repair and genome stability in bacteria.
- Rhizobium meliloti is a nitrogen-fixing bacterium important in agriculture.
- Bacteriophages can undergo induction, a process often linked to DNA damage responses.
Purpose of the Study:
- To isolate and characterize mutants of Rhizobium meliloti deficient in homologous genetic recombination.
- To investigate the role of homologous recombination in DNA repair and phage induction in Rhizobium meliloti.
Main Methods:
- Tn5 mutagenesis was used to generate mutants in Rhizobium meliloti 41.
- Mutants were screened for defects in homologous genetic recombination.
- UV sensitivity, phage 16-3 induction, and SOS activity were assessed.
Main Results:
- Two mutants deficient in homologous genetic recombination were isolated.
- These mutants exhibited increased sensitivity to UV light compared to the wild-type strain.
- The mutants showed defective induction of temperate phage 16-3 by UV-light, Mitomycin-C, and Bleomycin, and lacked SOS activity.
Conclusions:
- Homologous genetic recombination is essential for DNA repair and survival under genotoxic stress in Rhizobium meliloti.
- Deficiency in homologous recombination impacts phage induction pathways.
- The identified mutants provide tools for studying DNA repair and mutagenesis in Rhizobium meliloti.