Metabolite Profiling of Root Exudates of Common Bean under Phosphorus Deficiency

Tawaraya, Keitaro; Horie, Ryota; Saito, Saki; Wagatsuma, Tadao; Saito, Kazuki; Oikawa, Akira

doi:10.3390/metabo4030599

Cited by 64 publications

(46 citation statements)

References 24 publications

(26 reference statements)

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“…The web-based resource PIFAR allowed the identification of 175 gene products in P. aeruginosa putatively involved in the interaction with plants (Martinez-Garcia et al, 2016) and the TlpQ chemoreceptor was found to mediate chemotaxis toward the plant hormone ethylene (Kim et al, 2007). αKG is present at significant levels in plant root exudates (Tawaraya et al, 2014; Ganie et al, 2015) and chemotaxis to root exudate components was shown to be essential for efficient root colonization (de Weert et al, 2002; Scharf et al, 2016). …”

Section: Resultsmentioning

confidence: 99%

Identification of a Chemoreceptor in Pseudomonas aeruginosa That Specifically Mediates Chemotaxis Toward α-Ketoglutarate

et al. 2016

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Pseudomonas aeruginosa is an ubiquitous pathogen able to infect humans, animals, and plants. Chemotaxis was found to be associated with the virulence of this and other pathogens. Although established as a model for chemotaxis research, the majority of the 26 P. aeruginosa chemoreceptors remain functionally un-annotated. We report here the identification of PA5072 (named McpK) as chemoreceptor for α-ketoglutarate (αKG). High-throughput thermal shift assays and isothermal titration calorimetry studies (ITC) of the recombinant McpK ligand binding domain (LBD) showed that it recognizes exclusively α-ketoglutarate. The ITC analysis indicated that the ligand bound with positive cooperativity (Kd1 = 301 μM, Kd2 = 81 μM). McpK is predicted to possess a helical bimodular (HBM) type of LBD and this and other studies suggest that this domain type may be associated with the recognition of organic acids. Analytical ultracentrifugation (AUC) studies revealed that McpK-LBD is present in monomer-dimer equilibrium. Alpha-KG binding stabilized the dimer and dimer self-dissociation constants of 55 μM and 5.9 μM were derived for ligand-free and αKG-bound forms of McpK-LBD, respectively. Ligand-induced LBD dimer stabilization has been observed for other HBM domain containing receptors and may correspond to a general mechanism of this protein family. Quantitative capillary chemotaxis assays demonstrated that P. aeruginosa showed chemotaxis to a broad range of αKG concentrations with maximal responses at 500 μM. Deletion of the mcpK gene reduced chemotaxis over the entire concentration range to close to background levels and wild type like chemotaxis was recovered following complementation. Real-time PCR studies indicated that the presence of αKG does not modulate mcpK expression. Since αKG is present in plant root exudates it was investigated whether the deletion of mcpK altered maize root colonization. However, no significant changes with respect to the wild type strain were observed. The existence of a chemoreceptor specific for αKG may be due to its central metabolic role as well as to its function as signaling molecule. This work expands the range of known chemoreceptor types and underlines the important physiological role of chemotaxis toward tricarboxylic acid cycle intermediates.

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Section: Resultsmentioning

confidence: 99%

Identification of a Chemoreceptor in Pseudomonas aeruginosa That Specifically Mediates Chemotaxis Toward α-Ketoglutarate

et al. 2016

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“…Subsequent experiments were aimed at elucidating whether McpG-mediated taxis alters colonization of plant roots. Previous studies have shown that significant amounts of GABA are present in root exudates of different plants (Penrose and Glick, 2001;Carvalhais et al, 2011;Badri et al, 2013;Tawaraya et al, 2014). We therefore conducted studies to determine whether GABA is present in root exudates of our model plant, the saladet tomato variety.…”

Section: Mcpg Of P Putida Kt2440r Participates In Attraction To and mentioning

confidence: 99%

Specific gamma‐aminobutyrate chemotaxis in pseudomonads with different lifestyle

Reyes-Darias

García

Rico-Jiménez

et al. 2015

Molecular Microbiology

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SummaryThe PctC chemoreceptor of Pseudomonas aeruginosa mediates chemotaxis with high specificity to gammaaminobutyric acid (GABA). This compound is present everywhere in nature and has multiple functions, including being a human neurotransmitter or plant signaling compound. Because P. aeruginosa is ubiquitously distributed in nature and able to infect and colonize different hosts, the physiological relevance of GABA taxis is unclear, but it has been suggested that bacterial attraction to neurotransmitters may enhance virulence. We report the identification of McpG as a specific GABA chemoreceptor in nonpathogenic Pseudomonas putida KT2440. As with PctC, GABA was found to bind McpG tightly. The analysis of chimeras comprising the PctC and McpG ligand-binding domains fused to the Tar signaling domain showed very high GABA sensitivities. We also show that PctC inactivation does not alter virulence in Caenorhabditis elegans. Significant amounts of GABA were detected in tomato root exudates, and deletion of mcpG reduced root colonization that requires chemotaxis through agar. The C. elegans data and the detection of a GABA receptor in non-pathogenic species indicate that GABA taxis may not be related to virulence in animal systems but may be of importance in the context of colonization and infection of plant roots by soil-dwelling pseudomonads.

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“…Metabolites contained in common bean root exudates have been investigated in presence of different phosphorus concentrations. Organic acids and AA (Orn, Arg, Asp…) levels have been showing higher in the exudates in plants grown in absence of phosphate .…”

Section: Ce‐ms As a Metabolomic Toolmentioning

confidence: 97%

Recent advances in amino acid analysis by capillary electromigration methods, 2013–2015

et al. 2015

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We describe the most important research articles published on amino acid analysis using CE during the period from June 2013 to May 2015, and follows the format of the previous articles published in electrophoresis the new developments in amino acid analysis with CE are mainly describing improvements in detection means and injection methods. Enantiomeric separation developments are still important. Focusing the applications, we describe the neurochemical and clinical works, but also the metabolomic studies for which the publication number increase greatly. Finally, works focused on amino acids in food and agricultural applications are described.

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Metabolite Profiling of Root Exudates of Common Bean under Phosphorus Deficiency

Cited by 64 publications

References 24 publications

Identification of a Chemoreceptor in Pseudomonas aeruginosa That Specifically Mediates Chemotaxis Toward α-Ketoglutarate

Identification of a Chemoreceptor in Pseudomonas aeruginosa That Specifically Mediates Chemotaxis Toward α-Ketoglutarate

Specific gamma‐aminobutyrate chemotaxis in pseudomonads with different lifestyle

Recent advances in amino acid analysis by capillary electromigration methods, 2013–2015

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