Functional and expression analysis of the metal-inducible dmeRF system from Rhizobium legumionosarum bv. viciae


Autoria(s): Rubio Sanz, Laura; Prieto Carbajo, Rosa Isabel; Imperial Ródenas, Juan; Palacios Alberti, Jose Manuel; Brito Lopez, Maria Belen
Data(s)

01/08/2013

Resumo

A gene encoding a homolog to the cation diffusion facilitator protein DmeF from Cupriavidus metallidurans has been identified in the genome of Rhizobium leguminosarum UPM791. The R. leguminosarum dmeF gene is located downstream of an open reading frame (designated dmeR) encoding a protein homologous to the nickel- and cobalt-responsive transcriptional regulator RcnR from Escherichia coli. Analysis of gene expression showed that the R. leguminosarum dmeRF genes are organized as a transcriptional unit whose expression is strongly induced by nickel and cobalt ions, likely by alleviating the repressor activity of DmeR on dmeRF transcription. An R. leguminosarum dmeRF mutant strain displayed increased sensitivity to Co(II) and Ni(II), whereas no alterations of its resistance to Cd(II), Cu(II), or Zn(II) were observed. A decrease of symbiotic performance was observed when pea plants inoculated with an R. leguminosarum dmeRF deletion mutant strain were grown in the presence of high concentrations of nickel and cobalt. The same mutant induced significantly lower activity levels of NiFe hydrogenase in microaerobic cultures. These results indicate that the R. leguminosarum DmeRF system is a metal-responsive efflux mechanism acting as a key element for metal homeostasis in R. leguminosarum under free-living and symbiotic conditions. The presence of similar dmeRF gene clusters in other Rhizobiaceae suggests that the dmeRF system is a conserved mechanism for metal tolerance in legume endosymbiotic bacteria.

Formato

application/pdf

Identificador

http://oa.upm.es/21407/

Idioma(s)

eng

Publicador

E.U.I.T. Agrícola (UPM)

Relação

http://oa.upm.es/21407/1/INVE_MEM_2013_144808.pdf

info:eu-repo/semantics/altIdentifier/doi/10.1128/AEM.01954-13

Direitos

http://creativecommons.org/licenses/by-nc-nd/3.0/es/

info:eu-repo/semantics/openAccess

Fonte

Applied And Environmental Microbiology, ISSN 0099-2240, 2013-08, Vol. 79

Palavras-Chave #Biología
Tipo

info:eu-repo/semantics/article

Artículo

PeerReviewed