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Qiao M, Sun R, Wang Z, Dumack K, Xie X, Dai C, Wang E, Zhou J, Sun B, Peng X, Bonkowski M, Chen Y. Legume rhizodeposition promotes nitrogen fixation by soil microbiota under crop diversification. Nat Commun 2024; 15:2924. [PMID: 38575565 PMCID: PMC10995168 DOI: 10.1038/s41467-024-47159-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 03/22/2024] [Indexed: 04/06/2024] Open
Abstract
Biological nitrogen fixation by free-living bacteria and rhizobial symbiosis with legumes plays a key role in sustainable crop production. Here, we study how different crop combinations influence the interaction between peanut plants and their rhizosphere microbiota via metabolite deposition and functional responses of free-living and symbiotic nitrogen-fixing bacteria. Based on a long-term (8 year) diversified cropping field experiment, we find that peanut co-cultured with maize and oilseed rape lead to specific changes in peanut rhizosphere metabolite profiles and bacterial functions and nodulation. Flavonoids and coumarins accumulate due to the activation of phenylpropanoid biosynthesis pathways in peanuts. These changes enhance the growth and nitrogen fixation activity of free-living bacterial isolates, and root nodulation by symbiotic Bradyrhizobium isolates. Peanut plant root metabolites interact with Bradyrhizobium isolates contributing to initiate nodulation. Our findings demonstrate that tailored intercropping could be used to improve soil nitrogen availability through changes in the rhizosphere microbiome and its functions.
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Affiliation(s)
- Mengjie Qiao
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ruibo Sun
- Anhui Province Key Lab of Farmland Ecological Conservation and Nutrient Utilization, College of Resources and Environment, Anhui Agricultural University, Hefei, 230036, China
| | - Zixuan Wang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
- College of Land Resource and Environment, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Kenneth Dumack
- Terrestrial Ecology, Institute of Zoology, University of Cologne, Zülpicher Str 47b, Cologne, 50674, Germany
| | - Xingguang Xie
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Chuanchao Dai
- College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Ertao Wang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Jizhong Zhou
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, 73019, USA
| | - Bo Sun
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Xinhua Peng
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Michael Bonkowski
- Terrestrial Ecology, Institute of Zoology, University of Cologne, Zülpicher Str 47b, Cologne, 50674, Germany
- Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, 50674, Germany
| | - Yan Chen
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
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Albicoro FJ, Vacca C, Cafiero JH, Draghi WO, Martini MC, Goulian M, Lagares A, Del Papa MF. Comparative Proteomic Analysis Revealing ActJ-Regulated Proteins in Sinorhizobium meliloti. J Proteome Res 2023; 22:1682-1694. [PMID: 37017314 PMCID: PMC10834056 DOI: 10.1021/acs.jproteome.2c00731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023]
Abstract
To adapt to different environmental conditions, Sinorhizobium meliloti relies on finely tuned regulatory networks, most of which are unexplored to date. We recently demonstrated that deletion of the two-component system ActJK renders an acid-vulnerable phenotype in S. meliloti and negatively impacts bacteroid development and nodule occupancy as well. To fully understand the role of ActJ in acid tolerance, S. meliloti wild-type and S. meliloti ΔactJ proteomes were compared in the presence or absence of acid stress by nanoflow ultrahigh-performance liquid chromatography coupled to mass spectrometry. The analysis demonstrated that proteins involved in the synthesis of exopolysaccharides (EPSs) were notably enriched in ΔactJ cells in acid pH. Total EPS quantification further revealed that although EPS production was augmented at pH 5.6 in both the ΔactJ and the parental strain, the lack of ActJ significantly enhanced this difference. Moreover, several efflux pumps were found to be downregulated in the ΔactJ strain. Promoter fusion assays suggested that ActJ positively modulated its own expression in an acid medium but not at under neutral conditions. The results presented here identify several ActJ-regulated genes in S. meliloti, highlighting key components associated with ActJK regulation that will contribute to a better understanding of rhizobia adaptation to acid stress.
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Affiliation(s)
- Francisco Javier Albicoro
- Instituto de Biotecnología y Biologia Molecular -CONICET CCT La Plata - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Carolina Vacca
- Instituto de Biotecnología y Biologia Molecular -CONICET CCT La Plata - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Juan Hilario Cafiero
- Instituto de Biotecnología y Biologia Molecular -CONICET CCT La Plata - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Walter Omar Draghi
- Instituto de Biotecnología y Biologia Molecular -CONICET CCT La Plata - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - María Carla Martini
- Instituto de Biotecnología y Biologia Molecular -CONICET CCT La Plata - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Mark Goulian
- Department of Biology, University of Pennsylvania, Philadelphia, PA. USA
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA. USA
| | - Antonio Lagares
- Instituto de Biotecnología y Biologia Molecular -CONICET CCT La Plata - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - María Florencia Del Papa
- Instituto de Biotecnología y Biologia Molecular -CONICET CCT La Plata - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
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3
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Brito-Santana P, Duque-Pedraza JJ, Bernabéu-Roda LM, Carvia-Hermoso C, Cuéllar V, Fuentes-Romero F, Acosta-Jurado S, Vinardell JM, Soto MJ. Sinorhizobium meliloti DnaJ Is Required for Surface Motility, Stress Tolerance, and for Efficient Nodulation and Symbiotic Nitrogen Fixation. Int J Mol Sci 2023; 24:ijms24065848. [PMID: 36982921 PMCID: PMC10055731 DOI: 10.3390/ijms24065848] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/14/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
Bacterial surface motility is a complex microbial trait that contributes to host colonization. However, the knowledge about regulatory mechanisms that control surface translocation in rhizobia and their role in the establishment of symbiosis with legumes is still limited. Recently, 2-tridecanone (2-TDC) was identified as an infochemical in bacteria that hampers microbial colonization of plants. In the alfalfa symbiont Sinorhizobium meliloti, 2-TDC promotes a mode of surface motility that is mostly independent of flagella. To understand the mechanism of action of 2-TDC in S. meliloti and unveil genes putatively involved in plant colonization, Tn5 transposants derived from a flagellaless strain that were impaired in 2-TDC-induced surface spreading were isolated and genetically characterized. In one of the mutants, the gene coding for the chaperone DnaJ was inactivated. Characterization of this transposant and newly obtained flagella-minus and flagella-plus dnaJ deletion mutants revealed that DnaJ is essential for surface translocation, while it plays a minor role in swimming motility. DnaJ loss-of-function reduces salt and oxidative stress tolerance in S. meliloti and hinders the establishment of efficient symbiosis by affecting nodule formation efficiency, cellular infection, and nitrogen fixation. Intriguingly, the lack of DnaJ causes more severe defects in a flagellaless background. This work highlights the role of DnaJ in the free-living and symbiotic lifestyles of S. meliloti.
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Affiliation(s)
- Paula Brito-Santana
- Estación Experimental del Zaidín, CSIC, Department of Biotechnology and Environmental Protection, 18008 Granada, Spain
| | - Julián J Duque-Pedraza
- Estación Experimental del Zaidín, CSIC, Department of Biotechnology and Environmental Protection, 18008 Granada, Spain
| | - Lydia M Bernabéu-Roda
- Estación Experimental del Zaidín, CSIC, Department of Biotechnology and Environmental Protection, 18008 Granada, Spain
| | - Cristina Carvia-Hermoso
- Estación Experimental del Zaidín, CSIC, Department of Biotechnology and Environmental Protection, 18008 Granada, Spain
| | - Virginia Cuéllar
- Estación Experimental del Zaidín, CSIC, Department of Biotechnology and Environmental Protection, 18008 Granada, Spain
| | - Francisco Fuentes-Romero
- Facultad de Biología, Departamento de Microbiología, Universidad de Sevilla, 41012 Sevilla, Spain
| | - Sebastián Acosta-Jurado
- Centro Andaluz de Biología del Desarrollo, CSIC, Junta de Andalucía, Departamento de Biología Molecular e Ingeniería Bioquímica, Universidad Pablo de Olavide, 41013 Seville, Spain
| | - José-María Vinardell
- Facultad de Biología, Departamento de Microbiología, Universidad de Sevilla, 41012 Sevilla, Spain
| | - María J Soto
- Estación Experimental del Zaidín, CSIC, Department of Biotechnology and Environmental Protection, 18008 Granada, Spain
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M S, N RP, Rajendrasozhan S. Bacterial redox response factors in the management of environmental oxidative stress. World J Microbiol Biotechnol 2022; 39:11. [PMID: 36369499 DOI: 10.1007/s11274-022-03456-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 11/02/2022] [Indexed: 11/13/2022]
Abstract
Bacteria evolved to survive in the available environmental chemosphere via several cellular mechanisms. A rich pool of antioxidants and stress regulators plays a significant role in the survival of bacteria in unfavorable environmental conditions. Most of the microbes exhibit resistant phenomena in toxic environment niches. Naturally, bacteria possess efficient thioredoxin reductase, glutaredoxin, and peroxiredoxin redox systems to handle environmental oxidative stress. Further, an array of transcriptional regulators senses the oxidative stress conditions. Transcription regulators, such as OxyR, SoxRS, PerR, UspA, SsrB, MarA, OhrR, SarZ, etc., sense and transduce bacterial oxidative stress responses. The redox-sensitive transcription regulators continuously recycle the utilized antioxidant enzymes during oxidative stress. These regulators promote the expression of antioxidant enzymes such as superoxide dismutase, catalase, and peroxides that overcome oxidative insults. Therefore, the transcriptional regulations maintain steady-state activities of antioxidant enzymes representing the resistance against host cell/environmental oxidative insults. Further, the redox system provides reducing equivalents to synthesize biomolecules, thereby contributing to cellular repair mechanisms. The inactive transcriptional regulators in the undisturbed cells are activated by oxidative stress. The oxidized transcriptional regulators modulate the expression of antioxidant and cellular repair enzymes to survive in extreme environmental conditions. Therefore, targeting these antioxidant systems and response regulators could alter cellular redox homeostasis. This review presents the mechanisms of different redox systems that favor bacterial survival in extreme environmental oxidative stress conditions.
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Affiliation(s)
- Sudharsan M
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalainagar, Chidambaram, Tamil Nadu, 608 002, India
| | - Rajendra Prasad N
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalainagar, Chidambaram, Tamil Nadu, 608 002, India.
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5
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Minguillón S, Matamoros MA, Duanmu D, Becana M. Signaling by reactive molecules and antioxidants in legume nodules. THE NEW PHYTOLOGIST 2022; 236:815-832. [PMID: 35975700 PMCID: PMC9826421 DOI: 10.1111/nph.18434] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 07/29/2022] [Indexed: 06/15/2023]
Abstract
Legume nodules are symbiotic structures formed as a result of the interaction with rhizobia. Nodules fix atmospheric nitrogen into ammonia that is assimilated by the plant and this process requires strict metabolic regulation and signaling. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are involved as signal molecules at all stages of symbiosis, from rhizobial infection to nodule senescence. Also, reactive sulfur species (RSS) are emerging as important signals for an efficient symbiosis. Homeostasis of reactive molecules is mainly accomplished by antioxidant enzymes and metabolites and is essential to allow redox signaling while preventing oxidative damage. Here, we examine the metabolic pathways of reactive molecules and antioxidants with an emphasis on their functions in signaling and protection of symbiosis. In addition to providing an update of recent findings while paying tribute to original studies, we identify several key questions. These include the need of new methodologies to detect and quantify ROS, RNS, and RSS, avoiding potential artifacts due to their short lifetimes and tissue manipulation; the regulation of redox-active proteins by post-translational modification; the production and exchange of reactive molecules in plastids, peroxisomes, nuclei, and bacteroids; and the unknown but expected crosstalk between ROS, RNS, and RSS in nodules.
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Affiliation(s)
- Samuel Minguillón
- Departamento de BiologíaVegetal, Estación Experimental de Aula DeiConsejo Superior de Investigaciones CientíficasApartado 1303450080ZaragozaSpain
| | - Manuel A. Matamoros
- Departamento de BiologíaVegetal, Estación Experimental de Aula DeiConsejo Superior de Investigaciones CientíficasApartado 1303450080ZaragozaSpain
| | - Deqiang Duanmu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and TechnologyHuazhong Agricultural UniversityWuhan430070China
| | - Manuel Becana
- Departamento de BiologíaVegetal, Estación Experimental de Aula DeiConsejo Superior de Investigaciones CientíficasApartado 1303450080ZaragozaSpain
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6
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Yan J, Liang Q, Chai Z, Duan N, Li X, Liu Y, Yang N, Li M, Jin Y, Bai F, Wu W, Cheng Z. Glutathione Synthesis Regulated by CtrA Protects Ehrlichia chaffeensis From Host Cell Oxidative Stress. Front Microbiol 2022; 13:846488. [PMID: 35432225 PMCID: PMC9005958 DOI: 10.3389/fmicb.2022.846488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 02/08/2022] [Indexed: 11/13/2022] Open
Abstract
Ehrlichia chaffeensis, a small Gram-negative obligatory intracellular bacterium, infects human monocytes or macrophages, and causes human monocytic ehrlichiosis, one of the most prevalent, life-threatening emerging zoonoses. Reactive oxygen species are produced by the host immune cells in response to bacterial infections. The mechanisms exploited by E. chaffeensis to resist oxidative stress have not been comprehensively demonstrated. Here, we found that E. chaffeensis encodes two functional enzymes, GshA and GshB, to synthesize glutathione that confers E. chaffeensis the oxidative stress resistance, and that the expression of gshA and gshB is upregulated by CtrA, a global transcriptional regulator, upon oxidative stress. We found that in E. chaffeensis, the expression of gshA and gshB was upregulated upon oxidative stress using quantitative RT-PCR. Ehrlichia chaffeensis GshA or GshB restored the ability of Pseudomonas aeruginosa GshA or GshB mutant to cope with oxidative stress, respectively. Recombinant E. chaffeensis CtrA directly bound to the promoters of gshA and gshB, determined with electrophoretic mobility shift assay, and activated the expression of gshA and gshB determined with reporter assay. Peptide nucleic acid transfection of E. chaffeensis, which reduced the CtrA protein level, inhibited the oxidative stress-induced upregulation of gshA and gshB. Our findings provide insights into the function and regulation of the two enzymes critical for E. chaffeensis resistance to oxidative stress and may deepen our understanding of E. chaffeensis pathogenesis and adaptation in hosts.
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Affiliation(s)
- Jiaqi Yan
- Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Qi'an Liang
- Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Zhouyi Chai
- Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Nan Duan
- Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Xiaoxiao Li
- Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yajing Liu
- Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Nan Yang
- Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Meifang Li
- Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yongxin Jin
- Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Fang Bai
- Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Weihui Wu
- Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Zhihui Cheng
- Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
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Lantz MA, Boddicker AM, Kain MP, Berg OMC, Wham CD, Mosier AC. Physiology of the Nitrite-Oxidizing Bacterium Candidatus Nitrotoga sp. CP45 Enriched From a Colorado River. Front Microbiol 2021; 12:709371. [PMID: 34484146 PMCID: PMC8415719 DOI: 10.3389/fmicb.2021.709371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/19/2021] [Indexed: 11/13/2022] Open
Abstract
Nitrogen cycling microbes, including nitrite-oxidizing bacteria (NOB), perform critical ecosystem functions that help mitigate anthropogenic stresses and maintain ecosystem health. Activity of these beneficial nitrogen cycling microbes is dictated in part by the microorganisms’ response to physicochemical conditions, such as temperature, pH, and nutrient availability. NOB from the newly described Candidatus Nitrotoga genus have been detected in a wide range of habitats across the globe, yet only a few organisms within the genus have been physiologically characterized. For freshwater systems where NOB are critical for supporting aquatic life, Ca. Nitrotoga have been previously detected but little is known about the physiological potential of these organisms or their response to changing environmental conditions. Here, we determined functional response to environmental change for a representative freshwater species of Ca. Nitrotoga (Ca. Nitrotoga sp. CP45, enriched from a Colorado river). The physiological findings demonstrated that CP45 maintained nitrite oxidation at pH levels of 5–8, at temperatures from 4 to 28°C, and when incubated in the dark. Light exposure and elevated temperature (30°C) completely halted nitrite oxidation. Ca. Nitrotoga sp. CP45 maintained nitrite oxidation upon exposure to four different antibiotics, and potential rates of nitrite oxidation by river sediment communities were also resilient to antibiotic stress. We explored the Ca. Nitrotoga sp. CP45 genome to make predictions about adaptations to enable survival under specific conditions. Overall, these results contribute to our understanding of the versatility of a representative freshwater Ca. Nitrotoga sp. Identifying the specific environmental conditions that maximize NOB metabolic rates may ultimately direct future management decisions aimed at restoring impacted systems.
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Affiliation(s)
- Munira A Lantz
- Department of Integrative Biology, University of Colorado Denver, Denver, CO, United States
| | - Andrew M Boddicker
- Department of Integrative Biology, University of Colorado Denver, Denver, CO, United States
| | - Michael P Kain
- Department of Integrative Biology, University of Colorado Denver, Denver, CO, United States
| | - Owen M C Berg
- Department of Integrative Biology, University of Colorado Denver, Denver, CO, United States
| | - Courtney D Wham
- Department of Integrative Biology, University of Colorado Denver, Denver, CO, United States
| | - Annika C Mosier
- Department of Integrative Biology, University of Colorado Denver, Denver, CO, United States
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The PhoPR two-component system responds to oxygen deficiency and regulates the pathways for energy supply in Corynebacterium glutamicum. World J Microbiol Biotechnol 2021; 37:160. [PMID: 34436681 DOI: 10.1007/s11274-021-03131-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 08/18/2021] [Indexed: 10/20/2022]
Abstract
The PhoPR two-component system, a highly conserved system in corynebacteria and mycobacteria, is involved in the cellular response to environmental stress. When analysing the transcriptomic data of Corynebacterium glutamicum strains under different dissolved oxygen (DO) levels, PhoPR was found to be the most responsive two-component system to DO changes. Here, we systematically investigated the expression of PhoPR in response to different DO levels and its impact on genes related to global regulation and energy metabolism. Using Green fluorescent protein as a reporter, we confirmed that PhoPR was significantly upregulated upon decrease of DO. Through real-time quantitative PCR and electrophoretic mobility shift assay, we found that the effector protein PhoP directly activated glxR (encoding a global regulator), pfk and gapA (encoding the glycolytic enzymes) and ctaD (encoding cytochrome c in the electron transport chain), while downregulated aceE and gltA (encoding the TCA cycle enzymes). Overexpression of phoP or phoR resulted in a decreased intracellular NAD+/NADH ratio and increased intracellular ATP level, consistent with the gene expression changes regulated by PhoP. These results reveal the PhoPR system respond to oxygen deficiency and is responsible for the regulation of pathways involved in the sustainability of the energy levels required under low oxygen conditions. Our findings in this study not only provide new insights into the adaptation pathways of C. glutamicum in response to low oxygen conditions but also identify new possible genetic targets for the construction of the new cell factories aimed toward industrial applications.
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An F, Li N, Zhang L, Zheng W, Xing S, Tang G, Yan J, Yu L, Luo L. Identification of Sinorhizobium meliloti LsrB regulon. Acta Biochim Biophys Sin (Shanghai) 2021; 53:955-957. [PMID: 33871011 DOI: 10.1093/abbs/gmab054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Fang An
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Ningning Li
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Lanya Zhang
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Wenjia Zheng
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Shenghui Xing
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Guirong Tang
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Junhui Yan
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Liangliang Yu
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Li Luo
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, China
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10
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Zhou J, Wang Z, Mao Y, Wang L, Xiao T, Hu Y, Zhang Y, Ma Y. Proteogenomic analysis of pitaya reveals cold stress-related molecular signature. PeerJ 2020; 8:e8540. [PMID: 32095361 PMCID: PMC7020823 DOI: 10.7717/peerj.8540] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 01/09/2020] [Indexed: 11/20/2022] Open
Abstract
Pitayas (Hylocereus spp.) is an attractive, highly nutritious and commercially valuable tropical fruit. However, low-temperature damage limits crop production. Genome of pitaya has not been sequenced yet. In this study, we sequenced the transcriptome of pitaya as the reference and further investigated the proteome under low temperature. By RNAseq technique, approximately 25.3 million reads were obtained, and further trimmed and assembled into 81,252 unigene sequences. The unigenes were searched against UniProt, NR and COGs at NCBI, Pfam, InterPro and Kyoto Encyclopedia of Genes and Genomes (KEGG) database, and 57,905 unigenes were retrieved annotations. Among them, 44,337 coding sequences were predicted by Trandecoder (v2.0.1), which served as the reference database for label-free proteomic analysis study of pitaya. Here, we identified 116 Differentially Abundant Proteins (DAPs) associated with the cold stress in pitaya, of which 18 proteins were up-regulated and 98 proteins were down-regulated. KEGG analysis and other results showed that these DAPs mainly related to chloroplasts and mitochondria metabolism. In summary, chloroplasts and mitochondria metabolism-related proteins may play an important role in response to cold stress in pitayas.
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Affiliation(s)
- Junliang Zhou
- Guizhou Institute of Pomological Sciences, Guizhou Academy of Agricultural Sciences, Guiyang, Guizhou, China
| | - Zhuang Wang
- Guizhou Institute of Pomological Sciences, Guizhou Academy of Agricultural Sciences, Guiyang, Guizhou, China
| | - Yongya Mao
- Guizhou Institute of Pomological Sciences, Guizhou Academy of Agricultural Sciences, Guiyang, Guizhou, China
| | - Lijuan Wang
- Guizhou Institute of Pomological Sciences, Guizhou Academy of Agricultural Sciences, Guiyang, Guizhou, China
| | - Tujian Xiao
- Guizhou Institute of Pomological Sciences, Guizhou Academy of Agricultural Sciences, Guiyang, Guizhou, China
| | - Yang Hu
- Zhejiang Academy of Forestry, Hangzhou, Zhejiang, China.,Zhejiang Provincial Key Laboratory of Biological and Chemical Utilization of Forest Resources, Hangzhou, Zhejiang, China
| | - Yang Zhang
- Fudan University, Institutes of Biomedical Sciences, Shanghai, Shanghai, China
| | - Yuhua Ma
- Guizhou Institute of Pomological Sciences, Guizhou Academy of Agricultural Sciences, Guiyang, Guizhou, China
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Kullapanich C, Dubbs JM, Mongkolsuk S. Inactivation of the Agrobacterium tumefaciens ActSR system affects resistance to multiple stresses with increased H 2O 2 sensitivity due to reduced expression of hemH. MICROBIOLOGY-SGM 2020; 165:1117-1134. [PMID: 31339484 DOI: 10.1099/mic.0.000838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The Agrobacterium tumefaciens ActSR two-component regulatory system is a member of a homologous group of global redox-responsive regulatory systems that adjust the expression of energy-consuming and energy-supplying metabolic pathways in order to maintain cellular redox balance. In this study, the transcriptional organization of the hrpB-actSR locus was determined and the effect of actSR system inactivation on stress resistance was investigated. It was found that hrpB is transcribed as a monocistronic mRNA and actS is transcribed along with actR as a bicistronic mRNA, while actR is also transcribed as a monocistronic message. Each message is initiated from a separate promoter. Inactivation of actR resulted in decreased resistance to membrane stress (sodium dodecyl sulfate), acid stress (pH 5.5), iron starvation (bipyridyl) and iron excess (FeCl3), and antibiotic stress (tetracycline and ciprofloxacin). Resistance to oxidative stress in the form of organic peroxide (cumene hydroperoxide) increased, while resistance to inorganic peroxide (H2O2) decreased. An actR insertion mutant displayed reduced catalase activity, even though transcription of katA and catE remained unchanged. Complementation of the actR inactivation mutant with plasmid-encoded actR or overexpression of hemH, encoding ferrochelatase, restored wild-type catalase activity and H2O2 resistance levels. Gel mobility shift and hemH promoter-lacZ fusion results indicated that ActR is a positive regulator of hemH that binds directly to the hemH promoter region. Thus, inactivation of the A. tumefaciens ActSR system affects resistance to multiple stresses, including reduced resistance to H2O2 resulting from a reduction in catalase activity due to reduced expression of hemH.
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Affiliation(s)
- Chitrasak Kullapanich
- Program in Applied Biological Sciences, Chulabhorn Graduate Institute, Chulabhorn Royal Academy, Bangkok, Thailand
| | - James M Dubbs
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand.,Program in Applied Biological Sciences, Chulabhorn Graduate Institute, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Skorn Mongkolsuk
- Center of Excellence on Environmental Health and Toxicology, EHT Ministry of Education, Bangkok, Thailand.,Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand.,Program in Applied Biological Sciences, Chulabhorn Graduate Institute, Chulabhorn Royal Academy, Bangkok, Thailand
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Novel Genes and Regulators That Influence Production of Cell Surface Exopolysaccharides in Sinorhizobium meliloti. J Bacteriol 2018; 200:JB.00501-17. [PMID: 29158240 DOI: 10.1128/jb.00501-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 11/10/2017] [Indexed: 12/21/2022] Open
Abstract
Sinorhizobium meliloti is a soil-dwelling alphaproteobacterium that engages in a nitrogen-fixing root nodule symbiosis with leguminous plants. Cell surface polysaccharides are important both for adapting to stresses in the soil and for the development of an effective symbiotic interaction. Among the polysaccharides characterized to date, the acidic exopolysaccharides I (EPS-I; succinoglycan) and II (EPS-II; galactoglucan) are particularly important for protection from abiotic stresses, biofilm formation, root colonization, and infection of plant roots. Previous genetic screens discovered mutants with impaired EPS production, allowing the delineation of EPS biosynthetic pathways. Here we report on a genetic screen to isolate mutants with mucoid colonial morphologies that suggest EPS overproduction. Screening with Tn5-110, which allows the recovery of both null and upregulation mutants, yielded 47 mucoid mutants, most of which overproduce EPS-I; among the 30 unique genes and intergenic regions identified, 14 have not been associated with EPS production previously. We identified a new protein-coding gene, emmD, which may be involved in the regulation of EPS-I production as part of the EmmABC three-component regulatory circuit. We also identified a mutant defective in EPS-I production, motility, and symbiosis, where Tn5-110 was not responsible for the mutant phenotypes; these phenotypes result from a missense mutation in rpoA corresponding to the domain of the RNA polymerase alpha subunit known to interact with transcription regulators.IMPORTANCE The alphaproteobacterium Sinorhizobium meliloti converts dinitrogen to ammonium while inhabiting specialized plant organs termed root nodules. The transformation of S. meliloti from a free-living soil bacterium to a nitrogen-fixing plant symbiont is a complex developmental process requiring close interaction between the two partners. As the interface between the bacterium and its environment, the S. meliloti cell surface plays a critical role in adaptation to varied soil environments and in interaction with plant hosts. We isolated and characterized S. meliloti mutants with increased production of exopolysaccharides, key cell surface components. Our diverse set of mutants suggests roles for exopolysaccharide production in growth, metabolism, cell division, envelope homeostasis, biofilm formation, stress response, motility, and symbiosis.
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