Life in an arsenic-containing gold mine: genome and physiology of the autotrophic arsenite-oxidizing bacterium Rhizobium sp. NT-26

20 páginas: 2 tablas, 7 figuras. -- PMID: 23589360 [PubMed - in process]. -- PMCID: PMC3673622

Arsenic is widespread in the environment and its presence is a result of natural or anthropogenic activities. Microbes have developed different mechanisms to deal with toxic compounds such as arsenic and this is to resist or metabolize the compound. Here, we present the first reference set of genomic, transcriptomic and proteomic data of an Alphaproteobacterium isolated from an arsenic-containing goldmine: Rhizobium sp. NT-26. Although phylogenetically related to the plant-associated bacteria, this organism has lost the major colonizing capabilities needed for symbiosis with legumes. In contrast, the genome of Rhizobium sp. NT-26 comprises a megaplasmid containing the various genes, which enable it to metabolize arsenite. Remarkably, although the genes required for arsenite oxidation and flagellar motility/biofilm formation are carried by the megaplasmid and the chromosome, respectively, a coordinate regulation of these two mechanisms was observed. Taken together, these processes illustrate the impact environmental pressure can have on the evolution of bacterial genomes, improving the fitness of bacterial strains by the acquisition of novel functions.

This work was supported by the Universite´ de Strasbourg (UdS), the Consortium National de Recherche en Genomique (CNRG), the Centre National de la Recherche Scientifique (CNRS), the Australian Research Council (DP034305), the French Ministere de l’Enseignement Superieur et de la Recherche to J.A. and J.C.-A., the Direction Generale del’Armement to L.G., a studentship from the Agence Nationale de la Recherche (ANR) COBIAS project (PRECODD 2007) to M.M., and the Ecole Normale Superieure (ENS) of Lyon to F.L. The authors thank Mathieu Erhardt for the TEM observations and Ashleigh Clarke for her work on arsenic resistance in strain NT-26. This work was done in part in the frame of the Groupement de Recherche—Metabolisme del’Arsenic chez les Microorganismes (GDR2909-CNRS).

Peer reviewed