Identification and characterization of the PhhR regulon in Pseudomonas putida

Herrera, Carmen and Duque, Estrella and Rodríguez Herva, Jose Juan and Fernandez Escamilla, Ana and Ramos, Juan Luis (2010). Identification and characterization of the PhhR regulon in Pseudomonas putida. "Environmental Microbiology", v. 12 (n. 6); pp. 1427-1438. ISSN 1462-2912. https://doi.org/10.1111/j.1462-2920.2009.02124.x.

Description

Title: Identification and characterization of the PhhR regulon in Pseudomonas putida
Author/s:
  • Herrera, Carmen
  • Duque, Estrella
  • Rodríguez Herva, Jose Juan
  • Fernandez Escamilla, Ana
  • Ramos, Juan Luis
Item Type: Article
Título de Revista/Publicación: Environmental Microbiology
Date: June 2010
ISSN: 1462-2912
Volume: 12
Subjects:
Faculty: E.T.S.I. Agrónomos (UPM) [antigua denominación]
Department: Biotecnologia [hasta 2014]
Creative Commons Licenses: Recognition - No derivative works - Non commercial

Full text

[img]
Preview
PDF - Requires a PDF viewer, such as GSview, Xpdf or Adobe Acrobat Reader
Download (742kB) | Preview

Abstract

Pseudomonas putida is a soil microorganism that utilizes aromatic amino acids present in root exudates as a nitrogen source. We have previously shown that the PhhR transcriptional regulator induces phhAB genes encoding a phenylalanine hydroxylase. In this study we show, using microarray assays and promoter fusions, that PhhR is a global regulator responsible for the activation of genes essential for phenylalanine degradation, phenylalanine homeostasis and other genes of unknown function. Recently, it has been shown that phenylalanine catabolism occurs through more than one pathway. One of these possible pathways involves the metabolism of phenylalanine via tyrosine, p-hydroxyphenylpyruvate, and homogentisate. We identified two genes within this pathway that encode an acyl-CoA transferase involved in the metabolism of acetoacetate. All genes in this pathway were induced in response to phenylalanine in a PhhR-proficient background. The second potential degradative pathway involves the degradation of phenylalanine to produce phenylpyruvate, which seems to be degraded via phenylacetyl-CoA. A number of mutants in the paa genes encoding phenylacetyl-CoA degradation enzymes fail to grow on phenylpyruvate or phenylacetate, further supporting the existence of this second pathway. We found that the PhhR regulon also includes genes involved in the biosynthesis of aromatic amino acids that are repressed in the presence of phenylalanine, suggesting the possibility of feedback at the transcriptional level. In addition, we found that PhhR modulates the level of expression of the broad-substrate-specificity MexEF/OprN efflux pump. Expression from this pump is under the control of mexT gene product because phenylalanine-dependent transcription from the mexE promoter does not occur in a mexT mutant background. These results place PhhR as an important regulator in the control of bacterial responses to aromatic amino acids.

More information

Item ID: 8484
DC Identifier: http://oa.upm.es/8484/
OAI Identifier: oai:oa.upm.es:8484
DOI: 10.1111/j.1462-2920.2009.02124.x
Official URL: http://onlinelibrary.wiley.com/doi/10.1111/j.1462-2920.2009.02124.x/abstract;jsessionid=ADFA6AF069F2D94D70EDB0606A19CF6C.d01t03
Deposited by: Memoria Investigacion
Deposited on: 18 Aug 2011 09:35
Last Modified: 20 Apr 2016 17:15
  • Logo InvestigaM (UPM)
  • Logo GEOUP4
  • Logo Open Access
  • Open Access
  • Logo Sherpa/Romeo
    Check whether the anglo-saxon journal in which you have published an article allows you to also publish it under open access.
  • Logo Dulcinea
    Check whether the spanish journal in which you have published an article allows you to also publish it under open access.
  • Logo de Recolecta
  • Logo del Observatorio I+D+i UPM
  • Logo de OpenCourseWare UPM