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Hying ZT, Miller TJ, Loh CY, Bazurto JV. Glycine betaine metabolism is enabled in Methylorubrum extorquens PA1 by alterations to dimethylglycine dehydrogenase. Appl Environ Microbiol 2024:e0209023. [PMID: 38534142 DOI: 10.1128/aem.02090-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 02/22/2024] [Indexed: 03/28/2024] Open
Abstract
Low nutrient availability is a key characteristic of the phyllosphere (the aerial surface of plants). Phyllospheric bacteria utilize a wide array of carbon sources generated by plant hosts. Glycine betaine (GB) is a plant-derived compound that can be metabolized by certain members of the phyllosphere microbiota. Metabolism of glycine betaine generates formaldehyde, an intermediate of methylotrophic metabolism, leading us to investigate how the ubiquitous plant colonizing bacterium Methylorubrum extorquens PA1 might metabolize GB encountered in its native environment. M. extorquens PA1 cannot utilize GB as a sole carbon source. Through suppressor mutation analysis, we show that M. extorquens PA1 encodes a conserved GB utilization pathway that can be activated by single point mutations conferring GB utilization as a carbon source. We identified the gene cluster encoding the GB catabolic enzymes and found that gene expression was induced in the presence of GB. We show that utilization of GB is conserved among representative Methylobacterium species and generates the one-carbon metabolism intermediate formaldehyde, which M. extorquens utilizes as a source of energy. Our results support a model where suppressor mutations in Mext_3745 or ftsH (Mext_4840) prevent the degradation of the dimethylglycine dehydrogenase subunit DgcB by the membrane integral protease FtsH, conferring the ability to utilize GB by either (i) restoring stable membrane topology of DgcB or (ii) decreasing FtsH protease activity, respectively. Both mutations alleviate the bottleneck at the second step of GB degradation catalyzed by DgcAB.IMPORTANCEOvercoming low nutrient availability is a challenge many bacteria encounter in the environment. Facultative methylotrophs are able to utilize one-carbon and multi-carbon compounds as carbon and energy sources. The utilization of plant-derived glycine betaine (GB) represents a possible source of multi-carbon and one-carbon substrates. The metabolism of glycine betaine produces formaldehyde and glycine, which may be used simultaneously by facultative methylotrophs. However, the genes required for the utilization of GB in the ubiquitous plant-associated bacterium Methylorubrum extorquens have yet to be identified or described. Our work identifies and validates the genes required for glycine betaine metabolism in M. extorquens and shows that it directly intersects with methylotrophic metabolism through the production of formaldehyde.
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Affiliation(s)
- Zachary T Hying
- Department of Plant and Microbial Biology, University of Minnesota Twin Cities, St. Paul, Minnesota, USA
- Biotechnology Institute, University of Minnesota Twin Cities, St. Paul, Minnesota, USA
| | - Tyler J Miller
- Department of Plant and Microbial Biology, University of Minnesota Twin Cities, St. Paul, Minnesota, USA
- Biotechnology Institute, University of Minnesota Twin Cities, St. Paul, Minnesota, USA
| | - Chin Yi Loh
- Department of Plant and Microbial Biology, University of Minnesota Twin Cities, St. Paul, Minnesota, USA
- Biotechnology Institute, University of Minnesota Twin Cities, St. Paul, Minnesota, USA
| | - Jannell V Bazurto
- Department of Plant and Microbial Biology, University of Minnesota Twin Cities, St. Paul, Minnesota, USA
- Biotechnology Institute, University of Minnesota Twin Cities, St. Paul, Minnesota, USA
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Palberg D, Kaszecki E, Dhanjal C, Kisiała A, Morrison EN, Stock N, Emery RJN. Impact of glyphosate and glyphosate-based herbicides on phyllospheric Methylobacterium. BMC PLANT BIOLOGY 2024; 24:119. [PMID: 38369476 PMCID: PMC10875822 DOI: 10.1186/s12870-024-04818-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 02/12/2024] [Indexed: 02/20/2024]
Abstract
Symbiotic Methylobacterium comprise a significant portion of the phyllospheric microbiome, and are known to benefit host plant growth, development, and confer tolerance to stress factors. The near ubiquitous use of the broad-spectrum herbicide, glyphosate, in farming operations globally has necessitated a more expansive evaluation of the impacts of the agent itself and formulations containing glyphosate on important components of the plant phyllosphere, including Methylobacterium.This study provides an investigation of the sensitivity of 18 strains of Methylobacterium to glyphosate and two commercially available glyphosate-based herbicides (GBH). Nearly all strains of Methylobacterium showed signs of sensitivity to the popular GBH formulations WeatherMax® and Transorb® in a modified Kirby Bauer experiment. However, exposure to pure forms of glyphosate did not show a significant effect on growth for any strain in both the Kirby Bauer test and in liquid broth, until polysorbate-20 (Tween20) was added as a surfactant. Artificially increasing membrane permeability through the introduction of polysorbate-20 caused a 78-84% reduction in bacterial cell biomass relative to controls containing glyphosate or high levels of surfactant only (0-9% and 6-37% reduction respectively). Concentrations of glyphosate as low as 0.05% w/v (500 µg/L) from both commercial formulations tested, inhibited the culturability of Methylobacterium on fresh nutrient-rich medium.To better understand the compatibility of important phyllospheric bacteria with commercial glyphosate-based herbicides, this study endeavours to characterize sensitivity in multiple strains of Methylobacterium, and explore possible mechanisms by which toxicity may be induced.
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Affiliation(s)
- Daniel Palberg
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada
| | - Emma Kaszecki
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada
| | - Chetan Dhanjal
- Department of Biological Sciences, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA, 15213, USA
| | - Anna Kisiała
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada
| | - Erin N Morrison
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada
| | - Naomi Stock
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada
- Water Quality Centre, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada
| | - R J Neil Emery
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada.
- Department of Biology, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada.
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Klein VJ, Irla M, Gil López M, Brautaset T, Fernandes Brito L. Unravelling Formaldehyde Metabolism in Bacteria: Road towards Synthetic Methylotrophy. Microorganisms 2022; 10:microorganisms10020220. [PMID: 35208673 PMCID: PMC8879981 DOI: 10.3390/microorganisms10020220] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 12/26/2022] Open
Abstract
Formaldehyde metabolism is prevalent in all organisms, where the accumulation of formaldehyde can be prevented through the activity of dissimilation pathways. Furthermore, formaldehyde assimilatory pathways play a fundamental role in many methylotrophs, which are microorganisms able to build biomass and obtain energy from single- and multicarbon compounds with no carbon–carbon bonds. Here, we describe how formaldehyde is formed in the environment, the mechanisms of its toxicity to the cells, and the cell’s strategies to circumvent it. While their importance is unquestionable for cell survival in formaldehyde rich environments, we present examples of how the modification of native formaldehyde dissimilation pathways in nonmethylotrophic bacteria can be applied to redirect carbon flux toward heterologous, synthetic formaldehyde assimilation pathways introduced into their metabolism. Attempts to engineer methylotrophy into nonmethylotrophic hosts have gained interest in the past decade, with only limited successes leading to the creation of autonomous synthetic methylotrophy. Here, we discuss how native formaldehyde assimilation pathways can additionally be employed as a premise to achieving synthetic methylotrophy. Lastly, we discuss how emerging knowledge on regulation of formaldehyde metabolism can contribute to creating synthetic regulatory circuits applied in metabolic engineering strategies.
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Bazurto JV, Nayak DD, Ticak T, Davlieva M, Lee JA, Hellenbrand CN, Lambert LB, Benski OJ, Quates CJ, Johnson JL, Patel JS, Ytreberg FM, Shamoo Y, Marx CJ. EfgA is a conserved formaldehyde sensor that leads to bacterial growth arrest in response to elevated formaldehyde. PLoS Biol 2021; 19:e3001208. [PMID: 34038406 PMCID: PMC8153426 DOI: 10.1371/journal.pbio.3001208] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 03/25/2021] [Indexed: 01/07/2023] Open
Abstract
Normal cellular processes give rise to toxic metabolites that cells must mitigate. Formaldehyde is a universal stressor and potent metabolic toxin that is generated in organisms from bacteria to humans. Methylotrophic bacteria such as Methylorubrum extorquens face an acute challenge due to their production of formaldehyde as an obligate central intermediate of single-carbon metabolism. Mechanisms to sense and respond to formaldehyde were speculated to exist in methylotrophs for decades but had never been discovered. Here, we identify a member of the DUF336 domain family, named efgA for enhanced formaldehyde growth, that plays an important role in endogenous formaldehyde stress response in M. extorquens PA1 and is found almost exclusively in methylotrophic taxa. Our experimental analyses reveal that EfgA is a formaldehyde sensor that rapidly arrests growth in response to elevated levels of formaldehyde. Heterologous expression of EfgA in Escherichia coli increases formaldehyde resistance, indicating that its interaction partners are widespread and conserved. EfgA represents the first example of a formaldehyde stress response system that does not involve enzymatic detoxification. Thus, EfgA comprises a unique stress response mechanism in bacteria, whereby a single protein directly senses elevated levels of a toxic intracellular metabolite and safeguards cells from potential damage.
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Affiliation(s)
- Jannell V. Bazurto
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, Idaho, United States of America
- Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, Minnesota, United States of America
- Microbial and Plant Genomics Institute, University of Minnesota, Twin Cities, Minnesota, United States of America
- Biotechnology Institute, University of Minnesota, Twin Cities, Minnesota, United States of America
- * E-mail: (JVB); (CJM)
| | - Dipti D. Nayak
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America
- Department of Microbiology, University of Illinois, Urbana, Illinois, United States of America
| | - Tomislav Ticak
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, Idaho, United States of America
| | - Milya Davlieva
- Department of Biosciences, Rice University, Houston, Texas, United States of America
| | - Jessica A. Lee
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, Idaho, United States of America
- Space Biosciences Research Branch, NASA Ames Research Center, Moffett Field, California, United States of America
| | - Chandler N. Hellenbrand
- Department of Plant and Microbial Biology, University of Minnesota, Twin Cities, Minnesota, United States of America
| | - Leah B. Lambert
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Olivia J. Benski
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
| | - Caleb J. Quates
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
| | - Jill L. Johnson
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, Idaho, United States of America
| | - Jagdish Suresh Patel
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
| | - F. Marty Ytreberg
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, Idaho, United States of America
- Department of Physics, University of Idaho, Moscow, Idaho, United States of America
| | - Yousif Shamoo
- Department of Biosciences, Rice University, Houston, Texas, United States of America
| | - Christopher J. Marx
- Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America
- Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America
- Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, Idaho, United States of America
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States of America
- * E-mail: (JVB); (CJM)
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