Role of iron and the TonB system in colonization of corn seeds and roots by <i>Pseudomonas putida</i> KT2440

Molina, María Antonia; Godoy, Patricia; Ramos-González, Marı́a Isabel; Muñoz, Nuria Malajovich; Ramos, Juan L.; Espinosa‐Urgel, Manuel

doi:10.1111/j.1462-2920.2005.00720.x

Cited by 41 publications

(36 citation statements)

References 36 publications

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“…Thus, root microbiomes under the condition of low N input may be capable of catabolizing recalcitrant substances in the soil, such as aromatic compounds, as C, N and S sources to alleviate nutrient deficiencies. Abundant genes for Fe acquisition and transport (Table 2) may also accelerate competitive colonization by typical symbiotic bacteria like Pseudomonas putida KT2440 (36) of roots under poor nutrient conditions.…”

Section: Discussionmentioning

confidence: 99%

Low Nitrogen Fertilization Adapts Rice Root Microbiome to Low Nutrient Environment by Changing Biogeochemical Functions

et al. 2014

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Reduced fertilizer usage is one of the objectives of field management in the pursuit of sustainable agriculture. Here, we report on shifts of bacterial communities in paddy rice ecosystems with low (LN), standard (SN), and high (HN) levels of N fertilizer application (0, 30, and 300 kg N ha−1, respectively). The LN field had received no N fertilizer for 5 years prior to the experiment. The LN and HN plants showed a 50% decrease and a 60% increase in biomass compared with the SN plant biomass, respectively. Analyses of 16S rRNA genes suggested shifts of bacterial communities between the LN and SN root microbiomes, which were statistically confirmed by metagenome analyses. The relative abundances of Burkholderia, Bradyrhizobium and Methylosinus were significantly increased in root microbiome of the LN field relative to the SN field. Conversely, the abundance of methanogenic archaea was reduced in the LN field relative to the SN field. The functional genes for methane oxidation (pmo and mmo) and plant association (acdS and iaaMH) were significantly abundant in the LN root microbiome. Quantitative PCR of pmoA/mcrA genes and a 13C methane experiment provided evidence of more active methane oxidation in the rice roots of the LN field. In addition, functional genes for the metabolism of N, S, Fe, and aromatic compounds were more abundant in the LN root microbiome. These results suggest that low-N-fertilizer management is an important factor in shaping the microbial community structure containing key microbes for plant associations and biogeochemical processes in paddy rice ecosystems.

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Section: Discussionmentioning

confidence: 99%

Low Nitrogen Fertilization Adapts Rice Root Microbiome to Low Nutrient Environment by Changing Biogeochemical Functions

et al. 2014

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“…Apart from aromatic utilization, iron has been shown to play a significant role in various physiological attributes of P. putida, including root/seed colonization, motility, biofilm formation, biocontrol and pollutant degradation (Dinkla & Janssen, 2003;Dinkla et al, 2001;Fernández-Piñar et al, 2011;Molina et al, 2005Molina et al, , 2006. Therefore, one can presume that accelerated siderophore secretion will have multidimensionally positive impacts on the survival and proliferation of P. putida in its natural environment.…”

Section: Resultsmentioning

confidence: 99%

Pumping iron to keep fit: modulation of siderophore secretion helps efficient aromatic utilization in Pseudomonas putida KT2440

2014

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Studies of biotechnology applications of Pseudomonas putida KT2440 have been predominantly focused on regulation and expression of the toluene degradation (TOL) pathway. Unfortunately, there is limited information on the role of other physiological factors influencing aromatic utilization. In this report, we demonstrate that P. putida KT2440 increases its siderophore secretion in response to the availability of benzyl alcohol, a model aromatic substrate. It is argued that accelerated siderophore secretion in response to aromatic substrates provides an iron 'boost' which is required for the effective functioning of the iron-dependent oxygenases responsible for ring opening. Direct evidence for the cardinal role of siderophores in aromatic utilization is provided by evaluation of per capita siderophore secretion and comparative growth assessments of wild-type and siderophore-negative mutant strains grown on an alternative carbon source. Accelerated siderophore secretion can be viewed as a compensatory mechanism in P. putida in the context of its inability to secrete more than one type of siderophore (pyoverdine) or to utilize heterologous siderophores. Stimulated siderophore secretion might be a key factor in successful integration and proliferation of this organism as a bio-augmentation agent for aromatic degradation. It not only facilitates efficient aromatic utilization, but also provides better opportunities for iron assimilation amongst diverse microbial communities, thereby ensuring better survival and proliferation.

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“…Not surprisingly, iron is required for bacteria to colonize plants. Pseudomonas putida fails to colonize corn seeds following mutation of its TonB iron uptake system or addition of iron chelators to the corn spermosphere (37). Iron acquisition is a pathogenicity factor for both plant and animal bacterial pathogens (19,38).…”

Section: Discussionmentioning

confidence: 99%

Requirement of Siderophore Biosynthesis for Plant Colonization by Salmonella enterica

Hao

Willis

Andrews‐Polymenis

et al. 2012

Appl Environ Microbiol

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ABSTRACTContaminated fresh produce has become the number one vector of nontyphoidal salmonellosis to humans. However,Salmonella entericagenes essential for the life cycle of the organism outside the mammalian host are for the most part unknown. Screening deletion mutants led to the discovery that anaroAmutant had a significant root colonization defect due to a failure to replicate. AroA is part of the chorismic acid biosynthesis pathway, a central metabolic node involved in aromatic amino acid and siderophore production. Addition of tryptophan or phenylalanine to alfalfa root exudates did not restorearoAmutant replication. However, addition of ferrous sulfate restored replication of thearoAmutant, as well as alfalfa colonization. Tryptophan and phenylalanine auxotrophs had minor plant colonization defects, suggesting that suboptimal concentrations of these amino acids in root exudates were not major limiting factors forSalmonellareplication. AnentBmutant defective in siderophore biosynthesis had colonization and growth defects similar to those of thearoAmutant, and the defective phenotype was complemented by the addition of ferrous sulfate. Biosynthetic genes of eachSalmonellasiderophore, enterobactin and salmochelin, were upregulated in alfalfa root exudates, yet only enterobactin was sufficient for plant survival and persistence. Similar results in lettuce leaves indicate that siderophore biosynthesis is a widespread or perhaps universal plant colonization fitness factor forSalmonella, unlike phytobacterial pathogens, such asPseudomonasandXanthomonas.

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Role of iron and the TonB system in colonization of corn seeds and roots by Pseudomonas putida KT2440

Cited by 41 publications

References 36 publications

Low Nitrogen Fertilization Adapts Rice Root Microbiome to Low Nutrient Environment by Changing Biogeochemical Functions

Low Nitrogen Fertilization Adapts Rice Root Microbiome to Low Nutrient Environment by Changing Biogeochemical Functions

Pumping iron to keep fit: modulation of siderophore secretion helps efficient aromatic utilization in Pseudomonas putida KT2440

Requirement of Siderophore Biosynthesis for Plant Colonization by Salmonella enterica

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