Learn More
Based on the DNA sequence of the symbiotic plasmid of Rhizobium strain NGR234, we predicted potential rearrangements generated by homologous recombination. All predicted rearrangements were identified experimentally by using a PCR-based methodology. Thus, the predicted and the actual dynamic maps of the replicon coincide. By using an approach that does not(More)
Gene conversion is defined as the non-reciprocal transfer of information between homologous sequences. Despite methodological problems to establish non-reciprocity, gene conversion has been demonstrated in a wide variety of bacteria. Besides examples of high-frequency reversion of mutations in repeated genes, gene conversion in bacterial genomes has been(More)
BACKGROUND Symbiotic bacteria known as rhizobia interact with the roots of legumes and induce the formation of nitrogen-fixing nodules. In rhizobia, essential genes for symbiosis are compartmentalized either in symbiotic plasmids or in chromosomal symbiotic islands. To understand the structure and evolution of the symbiotic genome compartments (SGCs), it is(More)
Rhizobium leguminosarum bv. phaseoli CFN42 contains six plasmids (pa to pf), and pd has been shown to be the symbiotic plasmid. To determine the participation of the other plasmids in cellular functions, we used a positive selection scheme to isolate derivatives cured of each plasmid. These were obtained for all except one (pe), of which only deleted(More)
Bacteria belonging to the genus Rhizobium are able to develop two different lifestyles, in symbiotic association with plant roots or through saprophytic growth. The genome of Rhizobium strains is constituted by a chromosome and several large plasmids, one of them containing most of the genes involved in symbiosis (symbiotic plasmid or pSym). Our model(More)
Single-strand gaps (SSGs) and double-strand breaks (DSBs) are the major initiation sites for recombination. In bacteria, the SSGs are repaired by RecFOR, while the DSBs are processed by RecBCD in gram-negative bacteria and AddAB in gram-positive bacteria. Unexpectedly, instead of recBCD genes, the addAB genes were found in members of the(More)
Gene amplification is a common feature of the genome of prokaryotic organisms. In this review, we analyze different instances of gene amplification in a variety of prokaryotes, including their mechanisms of generation and biological role. Growing evidence supports the concept that gene amplification be considered not as a mutation but rather as a dynamic(More)
Replicon architecture in bacteria is commonly comprised of one indispensable chromosome and several dispensable plasmids. This view has been enriched by the discovery of additional chromosomes, identified mainly by localization of rRNA and/or tRNA genes, and also by experimental demonstration of their requirement for cell growth. The genome of Rhizobium(More)
BACKGROUND A traditional concept in bacterial genetics states that housekeeping genes, those involved in basic metabolic functions needed for maintenance of the cell, are encoded in the chromosome, whereas genes required for dealing with challenging environmental conditions are located in plasmids. Exceptions to this rule have emerged from genomic sequence(More)