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Wang P, Lopes LD, Lopez-Guerrero MG, van Dijk K, Alvarez S, Riethoven JJ, Schachtman DP. Natural variation in root exudation of GABA and DIMBOA impacts the maize root endosphere and rhizosphere microbiomes. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:5052-5066. [PMID: 35552399 DOI: 10.1093/jxb/erac202] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
Root exudates are important for shaping root-associated microbiomes. However, studies on a wider range of metabolites in exudates are required for a comprehensive understanding about their influence on microbial communities. We identified maize inbred lines that differ in exudate concentrations of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) and γ-aminobutyric acid (GABA) using a semi-hydroponic system. These lines were grown in the field to determine the changes in microbial diversity and gene expression due to varying concentrations of DIMBOA and GABA in exudates using 16S rRNA amplicon sequencing and metatranscriptomics. Results showed individual and interaction effects of DIMBOA and GABA on the rhizosphere and root endosphere β-diversity, most strongly at the V10 growth stage. The main bacterial families affected by both compounds were Ktedonobacteraceae and Xanthomonadaceae. Higher concentrations of DIMBOA in exudates affected the rhizosphere metatranscriptome, enriching for metabolic pathways associated with plant disease. This study validated the use of natural variation within plant species as a powerful approach for understanding the role of root exudates on microbiome selection. We also showed that a semi-hydroponic system can be used to identify maize genotypes that differ in GABA and DIMBOA exudate concentrations under field conditions. The impact of GABA exudation on root-associated microbiomes is shown for the first time.
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Affiliation(s)
- Peng Wang
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, USA and Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, USA
- Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Lucas Dantas Lopes
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, USA and Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, USA
- Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | | | - Karin van Dijk
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Sophie Alvarez
- Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
- Proteomics and Metabolomics Facility, Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Jean-Jack Riethoven
- Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
- Bioinformatics Core Facility, Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Daniel P Schachtman
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, USA and Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, USA
- Nebraska Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE, USA
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Sun Y, Mehmood A, Battino M, Xiao J, Chen X. Enrichment of Gamma-aminobutyric acid in foods: From conventional methods to innovative technologies. Food Res Int 2022; 162:111801. [DOI: 10.1016/j.foodres.2022.111801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 07/11/2022] [Accepted: 08/18/2022] [Indexed: 11/26/2022]
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Ferreiro MD, Gallegos MT. Distinctive features of the Gac-Rsm pathway in plant-associated Pseudomonas. Environ Microbiol 2021; 23:5670-5689. [PMID: 33939255 DOI: 10.1111/1462-2920.15558] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/29/2021] [Accepted: 05/01/2021] [Indexed: 02/04/2023]
Abstract
Productive plant-bacteria interactions, either beneficial or pathogenic, require that bacteria successfully sense, integrate and respond to continuously changing environmental and plant stimuli. They use complex signal transduction systems that control a vast array of genes and functions. The Gac-Rsm global regulatory pathway plays a key role in controlling fundamental aspects of the apparently different lifestyles of plant beneficial and phytopathogenic Pseudomonas as it coordinates adaptation and survival while either promoting plant health (biocontrol strains) or causing disease (pathogenic strains). Plant-interacting Pseudomonas stand out for possessing multiple Rsm proteins and Rsm RNAs, but the physiological significance of this redundancy is not yet clear. Strikingly, the components of the Gac-Rsm pathway and the controlled genes/pathways are similar, but the outcome of its regulation may be opposite. Therefore, identifying the target mRNAs bound by the Rsm proteins and their mode of action (repression or activation) is essential to explain the resulting phenotype. Some technical considerations to approach the study of this system are also given. Overall, several important features of the Gac-Rsm cascade are now understood in molecular detail, particularly in Pseudomonas protegens CHA0, but further questions remain to be solved in other plant-interacting Pseudomonas.
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Affiliation(s)
- María-Dolores Ferreiro
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ-CSIC), Granada, Spain
| | - María-Trinidad Gallegos
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ-CSIC), Granada, Spain
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Liang F, Zhang B, Yang Q, Zhang Y, Zheng D, Zhang LQ, Yan Q, Wu X. Cyclic-di-GMP Regulates the Quorum-Sensing System and Biocontrol Activity of Pseudomonas fluorescens 2P24 through the RsmA and RsmE Proteins. Appl Environ Microbiol 2020; 86:e02016-20. [PMID: 33036989 PMCID: PMC7688223 DOI: 10.1128/aem.02016-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 10/04/2020] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas fluorescens 2P24 is a rhizosphere bacterium that protects many crop plants against soilborne diseases caused by phytopathogens. The PcoI/PcoR quorum-sensing (QS) system and polyketide antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) are particularly relevant to the strain's biocontrol potential. In this study, we investigated the effects of c-di-GMP on the biocontrol activity of strain 2P24. The expression of the Escherichia coli diguanylate cyclase (YedQ) and phosphodiesterase (YhjH) in P. fluorescens 2P24 significantly increased and decreased the cellular concentration of c-di-GMP, respectively. The production of the QS signals N-acyl homoserine lactones (AHLs) and 2,4-DAPG was negatively regulated by c-di-GMP in 2P24. The regulatory proteins RsmA and RsmE were positively regulated by c-di-GMP. Genomic analysis revealed that 2P24 has 23 predicted proteins that contain c-di-GMP-synthesizing or -degrading domains. Among these proteins, C0J56_12915, C0J56_13325, and C0J56_27925 contributed to the production of c-di-GMP and were also involved in the regulation of the QS signal and antibiotic 2,4-DAPG production in P. fluorescens Overexpression of C0J56_12915, C0J56_13325, and C0J56_27925 in 2P24 impaired its root colonization and biocontrol activities. Taken together, these results demonstrated that c-di-GMP played an important role in fine-tuning the biocontrol traits of P. fluorescensIMPORTANCE In various bacteria, the bacterial second messenger c-di-GMP influences a wide range of cellular processes. However, the function of c-di-GMP on biocontrol traits in the plant-beneficial rhizobacteria remains largely unclear. The present work shows that the QS system and polyketide antibiotic 2,4-DAPG production are regulated by c-di-GMP through RsmA and RsmE proteins in P. fluorescens 2P24. The diguanylate cyclases (DGCs) C0J56_12915, C0J56_13325, and C0J56_27925 are especially involved in regulating the biocontrol traits of 2P24. Our work also demonstrated a connection between the Gac/Rsm cascade and the c-di-GMP signaling pathway in P. fluorescens.
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Affiliation(s)
- Fei Liang
- College of Agriculture, Guangxi University, Nanning, China
| | - Bo Zhang
- College of Agriculture, Guangxi University, Nanning, China
| | - Qingqing Yang
- College of Agriculture, Guangxi University, Nanning, China
| | - Yang Zhang
- College of Agriculture, Guangxi University, Nanning, China
| | - Dehong Zheng
- College of Agriculture, Guangxi University, Nanning, China
| | - Li-Qun Zhang
- College of Plant Protection, China Agricultural University, Beijing, China
| | - Qing Yan
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, Montana, USA
| | - Xiaogang Wu
- College of Agriculture, Guangxi University, Nanning, China
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Latour X. The Evanescent GacS Signal. Microorganisms 2020; 8:microorganisms8111746. [PMID: 33172195 PMCID: PMC7695008 DOI: 10.3390/microorganisms8111746] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 12/18/2022] Open
Abstract
The GacS histidine kinase is the membrane sensor of the major upstream two-component system of the regulatory Gac/Rsm signal transduction pathway. This pathway governs the expression of a wide range of genes in pseudomonads and controls bacterial fitness and motility, tolerance to stress, biofilm formation, and virulence or plant protection. Despite the importance of these roles, the ligands binding to the sensor domain of GacS remain unknown, and their identification is an exciting challenge in this domain. At high population densities, the GacS signal triggers a switch from primary to secondary metabolism and a change in bacterial lifestyle. It has been suggested, based on these observations, that the GacS signal is a marker of the emergence of nutritional stress and competition. Biochemical investigations have yet to characterize the GacS signal fully. However, they portray this cue as a low-molecular weight, relatively simple and moderately apolar metabolite possibly resembling, but nevertheless different, from the aliphatic organic acids acting as quorum-sensing signaling molecules in other Proteobacteria. Significant progress in the development of metabolomic tools and new databases dedicated to Pseudomonas metabolism should help to unlock some of the last remaining secrets of GacS induction, making it possible to control the Gac/Rsm pathway.
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Affiliation(s)
- Xavier Latour
- Laboratory of Microbiology Signals and Microenvironment (LMSM EA 4312), Normandy University (University of Rouen Normandy), 55 rue Saint-Germain, 27000 Evreux, France;
- Research Federation NORVEGE Fed4277, Normandy University, F-76821 Mont-Saint-Aignan, France
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Johanson DM, Goertz JE, Marin IA, Costello J, Overall CC, Gaultier A. Experimental autoimmune encephalomyelitis is associated with changes of the microbiota composition in the gastrointestinal tract. Sci Rep 2020; 10:15183. [PMID: 32938979 PMCID: PMC7494894 DOI: 10.1038/s41598-020-72197-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/26/2020] [Indexed: 02/06/2023] Open
Abstract
The gut microbiome is known to be sensitive to changes in the immune system, especially during autoimmune diseases such as Multiple Sclerosis (MS). Our study examines the changes to the gut microbiome that occur during experimental autoimmune encephalomyelitis (EAE), an animal model for MS. We collected fecal samples at key stages of EAE progression and quantified microbial abundances with 16S V3–V4 amplicon sequencing. Our analysis of the data suggests that the abundance of commensal Lactobacillaceae decreases during EAE while other commensal populations belonging to the Clostridiaceae, Ruminococcaceae, and Peptostreptococcaceae families expand. Community analysis with microbial co-occurrence networks points to these three expanding taxa as potential mediators of gut microbiome dysbiosis. We also employed PICRUSt2 to impute MetaCyc Enzyme Consortium (EC) pathway abundances from the original microbial abundance data. From this analysis, we found that a number of imputed EC pathways responsible for the production of immunomodulatory compounds appear to be enriched in mice undergoing EAE. Our analysis and interpretation of results provides a detailed picture of the changes to the gut microbiome that are occurring throughout the course of EAE disease progression and helps to evaluate EAE as a viable model for gut dysbiosis in MS patients.
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Affiliation(s)
- David M Johanson
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, 22908, USA.,Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Jennifer E Goertz
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, 22908, USA.,Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA.,Dept. of Neuroscience, Cornell University, Ithaca, NY, 14850, USA
| | - Ioana A Marin
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, 22908, USA.,Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA.,Dept. of Neuroscience, Stanford University, Stanford, CA, 94305, USA
| | - John Costello
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, 22908, USA.,Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA
| | - Christopher C Overall
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, 22908, USA.,Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA.,Myriad Genetics, Inc., San Francisco, CA, 94080, USA
| | - Alban Gaultier
- Center for Brain Immunology and Glia, University of Virginia, Charlottesville, VA, 22908, USA. .,Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA, 22908, USA.
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Tarkowski ŁP, Signorelli S, Höfte M. γ-Aminobutyric acid and related amino acids in plant immune responses: Emerging mechanisms of action. PLANT, CELL & ENVIRONMENT 2020; 43:1103-1116. [PMID: 31997381 DOI: 10.1111/pce.13734] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 01/17/2020] [Accepted: 01/22/2020] [Indexed: 06/10/2023]
Abstract
The entanglement between primary metabolism regulation and stress responses is a puzzling and fascinating theme in plant sciences. Among the major metabolites found in plants, γ-aminobutyric acid (GABA) fulfils important roles in connecting C and N metabolic fluxes through the GABA shunt. Activation of GABA metabolism is known since long to occur in plant tissues following biotic stresses, where GABA appears to have substantially different modes of action towards different categories of pathogens and pests. While it can harm insects thanks to its inhibitory effect on the neuronal transmission, its capacity to modulate the hypersensitive response in attacked host cells was proven to be crucial for host defences in several pathosystems. In this review, we discuss how plants can employ GABA's versatility to effectively deal with all the major biotic stressors, and how GABA can shape plant immune responses against pathogens by modulating reactive oxygen species balance in invaded plant tissues. Finally, we discuss the connections between GABA and other stress-related amino acids such as BABA (β-aminobutyric acid), glutamate and proline.
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Affiliation(s)
- Łukasz P Tarkowski
- Seed Metabolism and Stress Team, INRAE Angers, UMR1345 Institut de Recherche en Horticulture et Semences, Bâtiment A, Beaucouzé cedex, France
| | - Santiago Signorelli
- Laboratorio de Bioquímica, Departamento de Biología Vegetal, Facultad de Agronomía, Universidad de la República, Sayago CP, Montevideo, Uruguay
- The School of Molecular Sciences, Faculty of Science, The University of Western Australia, Crawley CP, WA, Australia
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley CP, WA, Australia
| | - Monica Höfte
- Laboratory of Phytopathology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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Tumewu SA, Matsui H, Yamamoto M, Noutoshi Y, Toyoda K, Ichinose Y. Requirement of γ-Aminobutyric Acid Chemotaxis for Virulence of Pseudomonas syringae pv. tabaci 6605. Microbes Environ 2020; 35:ME20114. [PMID: 33162464 PMCID: PMC7734410 DOI: 10.1264/jsme2.me20114] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 09/15/2020] [Indexed: 12/04/2022] Open
Abstract
γ-Aminobutyric acid (GABA) is a widely distributed non-proteinogenic amino acid that accumulates in plants under biotic and abiotic stress conditions. Recent studies suggested that GABA also functions as an intracellular signaling molecule in plants and in signals mediating interactions between plants and phytopathogenic bacteria. However, the molecular mechanisms underlying GABA responses to bacterial pathogens remain unknown. In the present study, a GABA receptor, named McpG, was conserved in the highly motile plant-pathogenic bacteria Pseudomonas syringae pv. tabaci 6605 (Pta6605). We generated a deletion mutant of McpG to further investigate its involvement in GABA chemotaxis using quantitative capillary and qualitative plate assays. The wild-type strain of Pta6605 was attracted to GABA, while the ΔmcpG mutant abolished chemotaxis to 10 mM GABA. However, ΔmcpG retained chemotaxis to proteinogenic amino acids and succinic semialdehyde, a structural analog of GABA. Furthermore, ΔmcpG was unable to effectively induce disease on host tobacco plants in three plant inoculation assays: flood, dip, and infiltration inoculations. These results revealed that the GABA sensing of Pta6605 is important for the interaction of Pta6605 with its host tobacco plant.
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Affiliation(s)
- Stephany Angelia Tumewu
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1–1–1, Kita-ku, Okayama 700–8530, Japan
| | - Hidenori Matsui
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1–1–1, Kita-ku, Okayama 700–8530, Japan
| | - Mikihiro Yamamoto
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1–1–1, Kita-ku, Okayama 700–8530, Japan
| | - Yoshiteru Noutoshi
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1–1–1, Kita-ku, Okayama 700–8530, Japan
| | - Kazuhiro Toyoda
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1–1–1, Kita-ku, Okayama 700–8530, Japan
| | - Yuki Ichinose
- Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1–1–1, Kita-ku, Okayama 700–8530, Japan
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Zhang Y, Zhang B, Wu X, Zhang LQ. Characterization the role of GacA-dependent small RNAs and RsmA family proteins on 2,4-diacetylphloroglucinol production in Pseudomonas fluorescens 2P24. Microbiol Res 2019; 233:126391. [PMID: 31865097 DOI: 10.1016/j.micres.2019.126391] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 11/26/2019] [Accepted: 12/07/2019] [Indexed: 10/25/2022]
Abstract
Pseudomonas fluorescens 2P24 is a plant-beneficial rhizobacteria that controls many root diseases caused by soil-borne pathogens, and the production of the antibiotic compound 2,4-diacetylphloroglucinol (2,4-DAPG) is essential for its biocontrol ability. In the present study, we investigated the regulatory mechanism acting on the production of 2,4-DAPG by the GacA-dependent small non-coding RNAs (sRNAs) and RsmA/E proteins in strain 2P24. Our results showed that the GacS-GacA system regulates the expression of the phlACBD locus, which is responsible for 2,4-DAPG production, by inducing the expression of rsmX, rsmX1, rsmY, and rsmZ. A novel GacA-regulated sRNA, RgsA, was found to negatively regulate 2,4-DAPG production. Activation of the phlACBD locus by the GacS-GacA system is mediated through RsmA and RsmE proteins (but not RsmI), which inhibit phlACBD translation by binding to the putative RsmA/E recognition element in the phlACBD leader. Taken together, our results suggested that in P. fluorescens 2P24, the GacS-GacA system controls the cellular 2,4-DAPG levels in the cell by fine-tuning the function of sRNAs in P. fluorescens.
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Affiliation(s)
- Yang Zhang
- College of Agriculture, Guangxi University, Nanning 530004, China
| | - Bo Zhang
- College of Agriculture, Guangxi University, Nanning 530004, China
| | - Xiaogang Wu
- College of Agriculture, Guangxi University, Nanning 530004, China.
| | - Li-Qun Zhang
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China.
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