toggle visibility Search & Display Options

Select All    Deselect All
 |   | 
Details
   print
  Records Links
Author (up) Donoso, R.; Leiva-Novoa, P.; Zuniga, A.; Timmermann, T.; Recabarren-Gajardo, G.; Gonzalez, B. pdf  doi
openurl 
  Title Biochemical and Genetic Bases of Indole-3-Acetic Acid (Auxin Phytohormone) Degradation by the Plant-Growth-Promoting Rhizobacterium Paraburkholderia phytofirmans PsJN Type
  Year 2017 Publication Applied And Environmental Microbiology Abbreviated Journal Appl. Environ. Microbiol.  
  Volume 83 Issue 1 Pages 20 pp  
  Keywords indole-3-acetic acid catabolism; iac genes; Paraburkholderia phytofirmans; plant-growth-promoting rhizobacteria  
  Abstract Several bacteria use the plant hormone indole-3-acetic acid (IAA) as a sole carbon and energy source. A cluster of genes (named iac) encoding IAA degradation has been reported in Pseudomonas putida 1290, but the functions of these genes are not completely understood. The plant-growth-promoting rhizobacterium Paraburkholderia phytofirmans PsJN harbors iac gene homologues in its genome, but with a different gene organization and context than those of P. putida 1290. The iac gene functions enable P. phytofirmans to use IAA as a sole carbon and energy source. Employing a heterologous expression system approach, P. phytofirmans iac genes with previously undescribed functions were associated with specific biochemical steps. In addition, two uncharacterized genes, previously unreported in P. putida and found to be related to major facilitator and tautomerase superfamilies, are involved in removal of an IAA metabolite called dioxindole-3-acetate. Similar to the case in strain 1290, IAA degradation proceeds through catechol as intermediate, which is subsequently degraded by ortho-ring cleavage. A putative two-component regulatory system and a LysR-type regulator, which apparently respond to IAA and dioxindole-3-acetate, respectively, are involved in iac gene regulation in P. phytofirmans. These results provide new insights about unknown gene functions and complex regulatory mechanisms in IAA bacterial catabolism. IMPORTANCE This study describes indole-3-acetic acid (auxin phytohormone) degradation in the well-known betaproteobacterium P. phytofirmans PsJN and comprises a complete description of genes, some of them with previously unreported functions, and the general basis of their gene regulation. This work contributes to the understanding of how beneficial bacteria interact with plants, helping them to grow and/or to resist environmental stresses, through a complex set of molecular signals, in this case through degradation of a highly relevant plant hormone.  
  Address [Donoso, Raul; Leiva-Novoa, Pablo; Zuniga, Ana; Timmermann, Tania; Gonzalez, Bernardo] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Santiago, Chile, Email: bernardo.gonzalez@uai.cl  
  Corporate Author Thesis  
  Publisher Amer Soc Microbiology Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0099-2240 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000393205400001 Approved  
  Call Number UAI @ eduardo.moreno @ Serial 699  
Permanent link to this record
 

 
Author (up) Perez-Pantoja, D.; Leiva-Novoa, P.; Donoso, R.A.; Little, C.; Godoy, M.; Pieper, D.H.; Gonzalez, B. pdf  doi
openurl 
  Title Hierarchy of Carbon Source Utilization in Soil Bacteria: Hegemonic Preference for Benzoate in Complex Aromatic Compound Mixtures Degraded by Cupriavidus pinatubonensis Strain JMP134 Type
  Year 2015 Publication Applied And Environmental Microbiology Abbreviated Journal Appl. Environ. Microbiol.  
  Volume 81 Issue 12 Pages 3914-3924  
  Keywords  
  Abstract Cupriavidus pinatubonensis JMP134, like many other environmental bacteria, uses a range of aromatic compounds as carbon sources. Previous reports have shown a preference for benzoate when this bacterium grows on binary mixtures composed of this aromatic compound and 4-hydroxybenzoate or phenol. However, this observation has not been extended to other aromatic mixtures resembling a more archetypal context. We carried out a systematic study on the substrate preference of C. pinatubonensis JMP134 growing on representative aromatic compounds channeled through different catabolic pathways described in aerobic bacteria. Growth tests of nearly the entire set of binary combinations and in mixtures composed of 5 or 6 aromatic components showed that benzoate and phenol were always the preferred and deferred growth substrates, respectively. This pattern was supported by kinetic analyses that showed shorter times to initiate consumption of benzoate in aromatic compound mixtures. Gene expression analysis by real-time reverse transcription-PCR (RT-PCR) showed that, in all mixtures, the repression by benzoate over other catabolic pathways was exerted mainly at the transcriptional level. Additionally, inhibition of benzoate catabolism suggests that its multiple repressive actions are not mediated by a sole mechanism, as suggested by dissimilar requirements of benzoate degradation for effective repression in different aromatic compound mixtures. The hegemonic preference for benzoate over multiple aromatic carbon sources is not explained on the basis of growth rate and/or biomass yield on each single substrate or by obvious chemical or metabolic properties of these aromatic compounds.  
  Address [Leiva-Novoa, Pablo; Donoso, Raul A.; Little, Cedric; Gonzalez, Bernardo] Univ Adolfo Ibanez, Ctr Appl Ecol & Sustainabil, Fac Ingn & Ciencias, Santiago, Chile, Email: bernardo.gonzalez@uai.cl  
  Corporate Author Thesis  
  Publisher Amer Soc Microbiology Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0099-2240 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000354864000002 Approved  
  Call Number UAI @ eduardo.moreno @ Serial 491  
Permanent link to this record
Select All    Deselect All
 |   | 
Details
   print

Save Citations:
Export Records: