1
|
Gonçalves R, Wamelink GWW, van der Putten P, Evers JB. Intercropping on Mars: A promising system to optimise fresh food production in future martian colonies. PLoS One 2024; 19:e0302149. [PMID: 38691526 PMCID: PMC11062560 DOI: 10.1371/journal.pone.0302149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 03/28/2024] [Indexed: 05/03/2024] Open
Abstract
Future colonists on Mars will need to produce fresh food locally to acquire key nutrients lost in food dehydration, the primary technique for sending food to space. In this study we aimed to test the viability and prospect of applying an intercropping system as a method for soil-based food production in Martian colonies. This novel approach to Martian agriculture adds valuable insight into how we can optimise resource use and enhance colony self-sustainability, since Martian colonies will operate under very limited space, energy, and Earth supplies. A likely early Martian agricultural setting was simulated using small pots, a controlled greenhouse environment, and species compliant with space mission requirements. Pea (Pisum sativum), carrot (Daucus carota) and tomato (Solanum lycopersicum) were grown in three soil types ("MMS-1" Mars regolith simulant, potting soil and sand), planted either mixed (intercropping) or separate (monocropping). Rhizobia bacteria (Rhizobium leguminosarum) were added as the pea symbiont for Nitrogen-fixing. Plant performance was measured as above-ground biomass (g), yield (g), harvest index (%), and Nitrogen/Phosphorus/Potassium content in yield (g/kg). The overall intercropping system performance was calculated as total relative yield (RYT). Intercropping had clear effects on plant performance in Mars regolith, being beneficial for tomato but mostly detrimental for pea and carrot, ultimately giving an overall yield disadvantage compared to monocropping (RYT = 0.93). This effect likely resulted from the observed absence of Rhizobia nodulation in Mars regolith, negating Nitrogen-fixation and preventing intercropped plants from leveraging their complementarity. Adverse regolith conditions-high pH, elevated compactness and nutrient deficiencies-presumably restricted Rhizobia survival/nodulation. In sand, where more favourable soil conditions promoted effective nodulation, intercropping significantly outperformed monocropping (RYT = 1.32). Given this, we suggest that with simple regolith improvements, enhancing conditions for nodulation, intercropping shows promise as a method for optimising food production in Martian colonies. Specific regolith ameliorations are proposed for future research.
Collapse
Affiliation(s)
- Rebeca Gonçalves
- Centre for Crop System Analysis, Wageningen University & Research, Wageningen, The Netherlands
| | - G. W. Wieger Wamelink
- Wageningen Environmental Research, Wageningen University & Research, Wageningen, The Netherlands
| | - Peter van der Putten
- Centre for Crop System Analysis, Wageningen University & Research, Wageningen, The Netherlands
| | - Jochem B. Evers
- Centre for Crop System Analysis, Wageningen University & Research, Wageningen, The Netherlands
| |
Collapse
|
2
|
Aroney STN, Pini F, Kessler C, Poole PS, Sánchez-Cañizares C. The motility and chemosensory systems of Rhizobium leguminosarum, their role in symbiosis, and link to PTS Ntr regulation. Environ Microbiol 2024; 26:e16570. [PMID: 38216524 DOI: 10.1111/1462-2920.16570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 12/13/2023] [Indexed: 01/14/2024]
Abstract
Motility and chemotaxis are crucial processes for soil bacteria and plant-microbe interactions. This applies to the symbiotic bacterium Rhizobium leguminosarum, where motility is driven by flagella rotation controlled by two chemotaxis systems, Che1 and Che2. The Che1 cluster is particularly important in free-living motility prior to the establishment of the symbiosis, with a che1 mutant delayed in nodulation and reduced in nodulation competitiveness. The Che2 system alters bacteroid development and nodule maturation. In this work, we also identified 27 putative chemoreceptors encoded in the R. leguminosarum bv. viciae 3841 genome and characterized its motility in different growth conditions. We describe a metabolism-based taxis system in rhizobia that acts at high concentrations of dicarboxylates to halt motility independent of chemotaxis. Finally, we show how PTSNtr influences cell motility, with PTSNtr mutants exhibiting reduced swimming in different media. Motility is restored by the active forms of the PTSNtr output regulatory proteins, unphosphorylated ManX and phosphorylated PtsN. Overall, this work shows how rhizobia typify soil bacteria by having a high number of chemoreceptors and highlights the importance of the motility and chemotaxis mechanisms in a free-living cell in the rhizosphere, and at different stages of the symbiosis.
Collapse
Affiliation(s)
| | | | - Celia Kessler
- Department of Biology, University of Oxford, Oxford, UK
| | | | | |
Collapse
|
3
|
Li X, Li Z. What determines symbiotic nitrogen fixation efficiency in rhizobium: recent insights into Rhizobium leguminosarum. Arch Microbiol 2023; 205:300. [PMID: 37542687 DOI: 10.1007/s00203-023-03640-7] [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: 06/01/2023] [Revised: 07/21/2023] [Accepted: 07/24/2023] [Indexed: 08/07/2023]
Abstract
Symbiotic nitrogen fixation (SNF) by rhizobium, a Gram-negative soil bacterium, is an essential component in the nitrogen cycle and is a sustainable green way to maintain soil fertility without chemical energy consumption. SNF, which results from the processes of nodulation, rhizobial infection, bacteroid differentiation and nitrogen-fixing reaction, requires the expression of various genes from both symbionts with adaptation to the changing environment. To achieve successful nitrogen fixation, rhizobia and their hosts cooperate closely for precise regulation of symbiotic genes, metabolic processes and internal environment homeostasis. Many researches have progressed to reveal the ample information about regulatory aspects of SNF during recent decades, but the major bottlenecks regarding improvement of nitrogen-fixing efficiency has proven to be complex. In this mini-review, we summarize recent advances that have contributed to understanding the rhizobial regulatory aspects that determine SNF efficiency, focusing on the coordinated regulatory mechanism of symbiotic genes, oxygen, carbon metabolism, amino acid metabolism, combined nitrogen, non-coding RNAs and internal environment homeostasis. Unraveling regulatory determinants of SNF in the nitrogen-fixing protagonist rhizobium is expected to promote an improvement of nitrogen-fixing efficiency in crop production.
Collapse
Affiliation(s)
- Xiaofang Li
- Institute of Biopharmaceuticals, Taizhou University, 1139 Shifu Avenue, Taizhou, 318000, China.
- School of Pharmaceutical Sciences, Taizhou University, 1139 Shifu Avenue, Taizhou, 318000, China.
| | - Zhangqun Li
- School of Pharmaceutical Sciences, Taizhou University, 1139 Shifu Avenue, Taizhou, 318000, China
| |
Collapse
|
4
|
Gómez-Godínez LJ, Aguirre-Noyola JL, Martínez-Romero E, Arteaga-Garibay RI, Ireta-Moreno J, Ruvalcaba-Gómez JM. A Look at Plant-Growth-Promoting Bacteria. PLANTS (BASEL, SWITZERLAND) 2023; 12:1668. [PMID: 37111891 PMCID: PMC10145503 DOI: 10.3390/plants12081668] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/06/2023] [Accepted: 03/23/2023] [Indexed: 06/19/2023]
Abstract
Bacteria have been used to increase crop yields. For their application on crops, bacteria are provided in inoculant formulations that are continuously changing, with liquid- and solid-based products. Bacteria for inoculants are mainly selected from natural isolates. In nature, microorganisms that favor plants exhibit various strategies to succeed and prevail in the rhizosphere, such as biological nitrogen fixation, phosphorus solubilization, and siderophore production. On the other hand, plants have strategies to maintain beneficial microorganisms, such as the exudation of chemoattractanst for specific microorganisms and signaling pathways that regulate plant-bacteria interactions. Transcriptomic approaches are helpful in attempting to elucidate plant-microorganism interactions. Here, we present a review of these issues.
Collapse
Affiliation(s)
- Lorena Jacqueline Gómez-Godínez
- Centro Nacional de Recursos Genéticos, Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, Tepatitlán de Morelos 47600, Jalisco, Mexico
| | - José Luis Aguirre-Noyola
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Av. Universidad s/n, Cuernavaca 62210, Morelos, Mexico
| | - Esperanza Martínez-Romero
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Av. Universidad s/n, Cuernavaca 62210, Morelos, Mexico
| | - Ramón Ignacio Arteaga-Garibay
- Centro Nacional de Recursos Genéticos, Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, Tepatitlán de Morelos 47600, Jalisco, Mexico
| | - Javier Ireta-Moreno
- Centro de Investigación Regional Pacífico Centro, Centro Altos Jalisco, Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, Tepatitlán de Morelos 2470, Jalisco, Mexico
| | - José Martín Ruvalcaba-Gómez
- Centro Nacional de Recursos Genéticos, Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, Tepatitlán de Morelos 47600, Jalisco, Mexico
| |
Collapse
|
5
|
Chaudhary S, Sindhu SS, Dhanker R, Kumari A. Microbes-mediated sulphur cycling in soil: Impact on soil fertility, crop production and environmental sustainability. Microbiol Res 2023; 271:127340. [PMID: 36889205 DOI: 10.1016/j.micres.2023.127340] [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: 11/24/2022] [Revised: 02/06/2023] [Accepted: 02/18/2023] [Indexed: 03/08/2023]
Abstract
Reduction in soil fertility and depletion of natural resources due to current intensive agricultural practices along with climate changes are the major constraints for crop productivity and global food security. Diverse microbial populations' inhabiting the soil and rhizosphere participate in biogeochemical cycling of nutrients and thereby, improve soil fertility and plant health, and reduce the adverse impact of synthetic fertilizers on the environment. Sulphur is 4th most common crucial macronutrient required by all organisms including plants, animals, humans and microorganisms. Effective strategies are required to enhance sulphur content in crops for minimizing adverse effects of sulphur deficiency on plants and humans. Various microorganisms are involved in sulphur cycling in soil through oxidation, reduction, mineralization, and immobilization, and volatalization processes of diverse sulphur compounds. Some microorganisms possess the unique ability to oxidize sulphur compounds into plant utilizable sulphate (SO42-) form. Considering the importance of sulphur as a nutrient for crops, many bacteria and fungi involved in sulphur cycling have been characterized from soil and rhizosphere. Some of these microbes have been found to positively affect plant growth and crop yield through multiple mechanisms including the enhanced mobilization of nutrients in soils (i.e., sulphate, phosphorus and nitrogen), production of growth-promoting hormones, inhibition of phytopathogens, protection against oxidative damage and mitigation of abiotic stresses. Application of these beneficial microbes as biofertilizers may reduce the conventional fertilizer application in soils. However, large-scale, well-designed, and long-term field trials are necessary to recommend the use of these microbes for increasing nutrient availability for growth and yield of crop plants. This review discusses the current knowledge regarding sulphur deficiency symptoms in plants, biogeochemical cycling of sulphur and inoculation effects of sulphur oxidizing microbes in improving plant biomass and crop yield in different crops.
Collapse
Affiliation(s)
- Suman Chaudhary
- Research Associate, EBL Laboratory, ICAR-Central Institute of Research on Buffaloes, Hisar 125001, Haryana, India.
| | - Satyavir Singh Sindhu
- Department of Microbiology, CCS Haryana Agricultural University, Hisar 125004, Haryana, India.
| | - Rinku Dhanker
- International Institute of Veterinary, Education & Research, Bahuakbarpur, Rohtak 124001, Haryana, India.
| | - Anju Kumari
- Center of Food Science and Technology, CCS Haryana Agricultural University, Hisar 125004, Haryana, India.
| |
Collapse
|
6
|
Zhang Y, Gallant É, Park JD, Seyedsayamdost MR. The Small-Molecule Language of Dynamic Microbial Interactions. Annu Rev Microbiol 2022; 76:641-660. [PMID: 35679616 PMCID: PMC10171915 DOI: 10.1146/annurev-micro-042722-091052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although microbes are routinely grown in monocultures in the laboratory, they are almost never encountered as single species in the wild. Our ability to detect and identify new microorganisms has advanced significantly in recent years, but our understanding of the mechanisms that mediate microbial interactions has lagged behind. What makes this task more challenging is that microbial alliances can be dynamic, consisting of multiple phases. The transitions between phases, and the interactions in general, are often mediated by a chemical language consisting of small molecules, also referred to as secondary metabolites or natural products. In this microbial lexicon, the molecules are like words and through their effects on recipient cells they convey meaning. The current review highlights three dynamic microbial interactions in which some of the words and their meanings have been characterized, especially those that mediate transitions in selected multiphasic associations. These systems provide insights into the principles that govern microbial symbioses and a playbook for interrogating similar associations in diverse ecological niches. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Yifan Zhang
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA; ,
| | - Étienne Gallant
- Department of Chemistry, Princeton University, Princeton, New Jersey, USA; ,
| | - Jong-Duk Park
- Department of Chemistry, Princeton University, Princeton, New Jersey, USA; ,
| | - Mohammad R Seyedsayamdost
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA; , .,Department of Chemistry, Princeton University, Princeton, New Jersey, USA; ,
| |
Collapse
|
7
|
Pardo-Diaz J, Beguerisse-Díaz M, Poole PS, Deane CM, Reinert G. Extracting Information from Gene Coexpression Networks of Rhizobium leguminosarum. J Comput Biol 2022; 29:752-768. [PMID: 35588362 DOI: 10.1089/cmb.2021.0600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Nitrogen uptake in legumes is facilitated by bacteria such as Rhizobium leguminosarum. For this bacterium, gene expression data are available, but functional gene annotation is less well developed than for other model organisms. More annotations could lead to a better understanding of the pathways for growth, plant colonization, and nitrogen fixation in R. leguminosarum. In this study, we present a pipeline that combines novel scores from gene coexpression network analysis in a principled way to identify the genes that are associated with certain growth conditions or highly coexpressed with a predefined set of genes of interest. This association may lead to putative functional annotation or to a prioritized list of genes for further study.
Collapse
Affiliation(s)
- Javier Pardo-Diaz
- Department of Statistics, University of Oxford, Oxford, United Kingdom.,Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | | | - Philip S Poole
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Charlotte M Deane
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Gesine Reinert
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
8
|
Abstract
Inoculation of cereals with diazotrophic (N2-fixing) bacteria offers a sustainable alternative to the application of nitrogen fertilizers in agriculture. While natural diazotrophs have evolved multilayered regulatory mechanisms that couple N2 fixation with assimilation of the product NH3 and prevent release to plants, genetic modifications can permit excess production and excretion of NH3. However, a lack of stringent host-specificity for root colonization by the bacteria would allow growth promotion of target and nontarget plants species alike. Here, we exploit synthetic transkingdom signaling to establish plant host-specific control of the N2-fixation catalyst nitrogenase in Azorhizobium caulinodans occupying barley roots. This work demonstrates how partner-specific interactions can be established to avoid potential growth promotion of nontarget plants. Engineering N2-fixing symbioses between cereals and diazotrophic bacteria represents a promising strategy to sustainably deliver biologically fixed nitrogen (N) in agriculture. We previously developed novel transkingdom signaling between plants and bacteria, through plant production of the bacterial signal rhizopine, allowing control of bacterial gene expression in association with the plant. Here, we have developed both a homozygous rhizopine producing (RhiP) barley line and a hybrid rhizopine uptake system that conveys upon our model bacterium Azorhizobium caulinodans ORS571 (Ac) 103-fold improved sensitivity for rhizopine perception. Using this improved genetic circuitry, we established tight rhizopine-dependent transcriptional control of the nitrogenase master regulator nifA and the N metabolism σ-factor rpoN, which drove nitrogenase expression and activity in vitro and in situ by bacteria colonizing RhiP barley roots. Although in situ nitrogenase activity was suboptimally effective relative to the wild-type strain, activation was specific to RhiP barley and was not observed on the roots of wild-type plants. This work represents a key milestone toward the development of a synthetic plant-controlled symbiosis in which the bacteria fix N2 only when in contact with the desired host plant and are prevented from interaction with nontarget plant species.
Collapse
|
9
|
NoiD, a DedA membrane protein required for homeostasis maintaining of Rhizobium leguminosarum biovar viciae during symbiosis with Pisum sativum. Symbiosis 2022. [DOI: 10.1007/s13199-021-00827-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
10
|
Abstract
Biological nitrogen fixation in rhizobium-legume symbioses is of major importance for sustainable agricultural practices. To establish a mutualistic relationship with their plant host, rhizobia transition from free-living bacteria in soil to growth down infection threads inside plant roots and finally differentiate into nitrogen-fixing bacteroids. We reconstructed a genome-scale metabolic model for Rhizobium leguminosarum and integrated the model with transcriptome, proteome, metabolome, and gene essentiality data to investigate nutrient uptake and metabolic fluxes characteristic of these different lifestyles. Synthesis of leucine, polyphosphate, and AICAR is predicted to be important in the rhizosphere, while myo-inositol catabolism is active in undifferentiated nodule bacteria in agreement with experimental evidence. The model indicates that bacteroids utilize xylose and glycolate in addition to dicarboxylates, which could explain previously described gene expression patterns. Histidine is predicted to be actively synthesized in bacteroids, consistent with transcriptome and proteome data for several rhizobial species. These results provide the basis for targeted experimental investigation of metabolic processes specific to the different stages of the rhizobium-legume symbioses. IMPORTANCE Rhizobia are soil bacteria that induce nodule formation on plant roots and differentiate into nitrogen-fixing bacteroids. A detailed understanding of this complex symbiosis is essential for advancing ongoing efforts to engineer novel symbioses with cereal crops for sustainable agriculture. Here, we reconstruct and validate a genome-scale metabolic model for Rhizobium leguminosarum bv. viciae 3841. By integrating the model with various experimental data sets specific to different stages of symbiosis formation, we elucidate the metabolic characteristics of rhizosphere bacteria, undifferentiated bacteria inside root nodules, and nitrogen-fixing bacteroids. Our model predicts metabolic flux patterns for these three distinct lifestyles, thus providing a framework for the interpretation of genome-scale experimental data sets and identifying targets for future experimental studies.
Collapse
|
11
|
Abstract
This article comments on: Tian L, Liu L, Xu S, Deng R, Wu P, Jiang H, Wu G, Chen Y. 2022. A d-pinitol transporter, LjPLT11, regulates plant growth and nodule development in Lotus japonicus. Journal of Experimental Botany 73, 351–365.
Collapse
Affiliation(s)
- Philip S Poole
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - Raphael Ledermann
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| |
Collapse
|
12
|
Webb IUC, Xu J, Sánchez-Cañizares C, Karunakaran R, Ramachandran VK, Rutten PJ, East AK, Huang WE, Watmough NJ, Poole PS. Regulation and Characterization of Mutants of fixABCX in Rhizobium leguminosarum. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1167-1180. [PMID: 34110256 DOI: 10.1094/mpmi-02-21-0037-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Symbiosis between Rhizobium leguminosarum and Pisum sativum requires tight control of redox balance in order to maintain respiration under the microaerobic conditions required for nitrogenase while still producing the eight electrons and sixteen molecules of ATP needed for nitrogen fixation. FixABCX, a cluster of electron transfer flavoproteins essential for nitrogen fixation, is encoded on the Sym plasmid (pRL10), immediately upstream of nifA, which encodes the general transcriptional regulator of nitrogen fixation. There is a symbiotically regulated NifA-dependent promoter upstream of fixA (PnifA1), as well as an additional basal constitutive promoter driving background expression of nifA (PnifA2). These were confirmed by 5'-end mapping of transcription start sites using differential RNA-seq. Complementation of polar fixAB and fixX mutants (Fix- strains) confirmed expression of nifA from PnifA1 in symbiosis. Electron microscopy combined with single-cell Raman microspectroscopy characterization of fixAB mutants revealed previously unknown heterogeneity in bacteroid morphology within a single nodule. Two morphotypes of mutant fixAB bacteroids were observed. One was larger than wild-type bacteroids and contained high levels of polyhydroxy-3-butyrate, a complex energy/reductant storage product. A second bacteroid phenotype was morphologically and compositionally different and resembled wild-type infection thread cells. From these two characteristic fixAB mutant bacteroid morphotypes, inferences can be drawn on the metabolism of wild-type nitrogen-fixing bacteroids.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
Collapse
Affiliation(s)
- Isabel U C Webb
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, U.K
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, U.K
| | - Jiabao Xu
- Department of Engineering, University of Oxford, Parks Road, Oxford OX1 3PJ, U.K
| | | | - Ramakrishnan Karunakaran
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, U.K
| | - Vinoy K Ramachandran
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, U.K
| | - Paul J Rutten
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, U.K
| | - Alison K East
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, U.K
| | - Wei E Huang
- Department of Engineering, University of Oxford, Parks Road, Oxford OX1 3PJ, U.K
| | - Nicholas J Watmough
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, U.K
| | - Philip S Poole
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, U.K
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, U.K
| |
Collapse
|
13
|
Schulte CCM, Borah K, Wheatley RM, Terpolilli JJ, Saalbach G, Crang N, de Groot DH, Ratcliffe RG, Kruger NJ, Papachristodoulou A, Poole PS. Metabolic control of nitrogen fixation in rhizobium-legume symbioses. SCIENCE ADVANCES 2021; 7:7/31/eabh2433. [PMID: 34330708 PMCID: PMC8324050 DOI: 10.1126/sciadv.abh2433] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 06/14/2021] [Indexed: 05/16/2023]
Abstract
Rhizobia induce nodule formation on legume roots and differentiate into bacteroids, which catabolize plant-derived dicarboxylates to reduce atmospheric N2 into ammonia. Despite the agricultural importance of this symbiosis, the mechanisms that govern carbon and nitrogen allocation in bacteroids and promote ammonia secretion to the plant are largely unknown. Using a metabolic model derived from genome-scale datasets, we show that carbon polymer synthesis and alanine secretion by bacteroids facilitate redox balance in microaerobic nodules. Catabolism of dicarboxylates induces not only a higher oxygen demand but also a higher NADH/NAD+ ratio than sugars. Modeling and 13C metabolic flux analysis indicate that oxygen limitation restricts the decarboxylating arm of the tricarboxylic acid cycle, which limits ammonia assimilation into glutamate. By tightly controlling oxygen supply and providing dicarboxylates as the energy and electron source donors for N2 fixation, legumes promote ammonia secretion by bacteroids. This is a defining feature of rhizobium-legume symbioses.
Collapse
Affiliation(s)
- Carolin C M Schulte
- Department of Plant Sciences, University of Oxford, Oxford, UK
- Department of Engineering Science, University of Oxford, Oxford, UK
| | - Khushboo Borah
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | | | | | | | - Nick Crang
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Daan H de Groot
- Systems Biology Lab, AIMMS, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | | | | | | | - Philip S Poole
- Department of Plant Sciences, University of Oxford, Oxford, UK.
- John Innes Centre, Norwich Research Park, Norwich, UK
| |
Collapse
|
14
|
Multiple sensors provide spatiotemporal oxygen regulation of gene expression in a Rhizobium-legume symbiosis. PLoS Genet 2021; 17:e1009099. [PMID: 33539353 PMCID: PMC7888657 DOI: 10.1371/journal.pgen.1009099] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 02/17/2021] [Accepted: 12/04/2020] [Indexed: 01/04/2023] Open
Abstract
Regulation by oxygen (O2) in rhizobia is essential for their symbioses with plants and involves multiple O2 sensing proteins. Three sensors exist in the pea microsymbiont Rhizobium leguminosarum Rlv3841: hFixL, FnrN and NifA. At low O2 concentrations (1%) hFixL signals via FxkR to induce expression of the FixK transcription factor, which activates transcription of downstream genes. These include fixNOQP, encoding the high-affinity cbb3-type terminal oxidase used in symbiosis. In free-living Rlv3841, the hFixL-FxkR-FixK pathway was active at 1% O2, and confocal microscopy showed hFixL-FxkR-FixK activity in the earliest stages of Rlv3841 differentiation in nodules (zones I and II). Work on Rlv3841 inside and outside nodules showed that the hFixL-FxkR-FixK pathway also induces transcription of fnrN at 1% O2 and in the earliest stages of Rlv3841 differentiation in nodules. We confirmed past findings suggesting a role for FnrN in fixNOQP expression. However, unlike hFixL-FxkR-FixK, Rlv3841 FnrN was only active in the near-anaerobic zones III and IV of pea nodules. Quantification of fixNOQP expression in nodules showed this was driven primarily by FnrN, with minimal direct hFixL-FxkR-FixK induction. Thus, FnrN is key for full symbiotic expression of fixNOQP. Without FnrN, nitrogen fixation was reduced by 85% in Rlv3841, while eliminating hFixL only reduced fixation by 25%. The hFixL-FxkR-FixK pathway effectively primes the O2 response by increasing fnrN expression in early differentiation (zones I-II). In zone III of mature nodules, near-anaerobic conditions activate FnrN, which induces fixNOQP transcription to the level required for wild-type nitrogen fixation activity. Modelling and transcriptional analysis indicates that the different O2 sensitivities of hFixL and FnrN lead to a nuanced spatiotemporal pattern of gene regulation in different nodule zones in response to changing O2 concentration. Multi-sensor O2 regulation is prevalent in rhizobia, suggesting the fine-tuned control this enables is common and maximizes the effectiveness of the symbioses. Rhizobia are soil bacteria that form a symbiosis with legume plants. In exchange for shelter from the plant, rhizobia provide nitrogen fertilizer, produced by nitrogen fixation. Fixation is catalysed by the nitrogenase enzyme, which is inactivated by oxygen. To prevent this, plants house rhizobia in root nodules, which create a low oxygen environment. However, rhizobia need oxygen, and must adapt to survive the low oxygen concentration in the nodule. Key to this is regulating their genes based on oxygen concentration. We studied one Rhizobium species which uses three different protein sensors of oxygen, each turning on at a different oxygen concentration. As the bacteria get deeper inside the plant nodule and the oxygen concentration drops, each sensor switches on in turn. Our results also show that the first sensor to turn on, hFixL, primes the second sensor, FnrN. This prepares the rhizobia for the core region of the nodule where oxygen concentration is lowest and most nitrogen fixation takes place. If both sensors are removed, the bacteria cannot fix nitrogen. Many rhizobia have several oxygen sensing proteins, so using multiple sensors is likely a common strategy enabling rhizobia to adapt to low oxygen precisely and in stages during symbiosis.
Collapse
|
15
|
Abstract
Rhizobia are a phylogenetically diverse group of soil bacteria that engage in mutualistic interactions with legume plants. Although specifics of the symbioses differ between strains and plants, all symbioses ultimately result in the formation of specialized root nodule organs which host the nitrogen-fixing microsymbionts called bacteroids. Inside nodules, bacteroids encounter unique conditions that necessitate global reprogramming of physiological processes and rerouting of their metabolism. Decades of research have addressed these questions using genetics, omics approaches, and more recently computational modelling. Here we discuss the common adaptations of rhizobia to the nodule environment that define the core principles of bacteroid functioning. All bacteroids are growth-arrested and perform energy-intensive nitrogen fixation fueled by plant-provided C4-dicarboxylates at nanomolar oxygen levels. At the same time, bacteroids are subject to host control and sanctioning that ultimately determine their fitness and have fundamental importance for the evolution of a stable mutualistic relationship.
Collapse
|
16
|
Pardo-Diaz J, Bozhilova LV, Beguerisse-Díaz M, Poole PS, Deane CM, Reinert G. Robust gene coexpression networks using signed distance correlation. Bioinformatics 2021; 37:btab041. [PMID: 33523234 PMCID: PMC8557847 DOI: 10.1093/bioinformatics/btab041] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 11/30/2020] [Accepted: 01/21/2021] [Indexed: 12/30/2022] Open
Abstract
MOTIVATION Even within well studied organisms, many genes lack useful functional annotations. One way to generate such functional information is to infer biological relationships between genes/proteins, using a network of gene coexpression data that includes functional annotations. However, the lack of trustworthy functional annotations can impede the validation of such networks. Hence, there is a need for a principled method to construct gene coexpression networks that capture biological information and are structurally stable even in the absence of functional information. RESULTS We introduce the concept of signed distance correlation as a measure of dependency between two variables, and apply it to generate gene coexpression networks. Distance correlation offers a more intuitive approach to network construction than commonly used methods such as Pearson correlation and mutual information. We propose a framework to generate self-consistent networks using signed distance correlation purely from gene expression data, with no additional information. We analyse data from three different organisms to illustrate how networks generated with our method are more stable and capture more biological information compared to networks obtained from Pearson correlation or mutual information. SUPPLEMENTARY INFORMATION Supplementary Information and code are available at Bioinformatics and https://github.com/javier-pardodiaz/sdcorGCN online.
Collapse
Affiliation(s)
- Javier Pardo-Diaz
- Department of Statistics, University of Oxford, Oxford OX1 3LB, UK
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
| | | | | | - Philip S Poole
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
| | | | - Gesine Reinert
- Department of Statistics, University of Oxford, Oxford OX1 3LB, UK
| |
Collapse
|
17
|
Antioxidant ability of glutaredoxins and their role in symbiotic nitrogen fixation in Rhizobium leguminosarum bv. viciae 3841. Appl Environ Microbiol 2021; 87:AEM.01956-20. [PMID: 33277272 PMCID: PMC7851698 DOI: 10.1128/aem.01956-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Glutaredoxins (Grx) are redoxin family proteins that reduce disulfides and mixed disulfides between glutathione and proteins. Rhizobium leguminosarum bv. Viciae 3841 contains three genes coding for glutaredoxins: RL4289 (grxA) codes for a dithiolic glutaredoxin, RL2615 (grxB) codes for a monothiol glutaredoxin, while RL4261 (grxC) codes for a glutaredoxin-like NrdH protein. We generated mutants interrupted in one, two, or three glutaredoxin genes. These mutants had no obvious differences in growth phenotypes from the wild type RL3841. However, while a mutant of grxC did not affect the antioxidant or symbiotic capacities of R. leguminosarum, grxA-derived or grxB mutants decreased antioxidant and nitrogen fixation capacities. Furthermore, grxA mutants were severely impaired in rhizosphere colonization, and formed smaller nodules with defects of bacteroid differentiation, whereas nodules induced by grxB mutants contained abnormally thick cortices and prematurely senescent bacteroids. The grx triple mutant had the greatest defect in antioxidant and symbiotic capacities of R. leguminosarum and quantitative proteomics revealed it had 56 up-regulated and 81 down-regulated proteins relative to wildtype. Of these proteins, twenty-eight are involved in transporter activity, twenty are related to stress response and virulence, and sixteen are involved in amino acid metabolism. Overall, R. leguminosarum glutaredoxins behave as antioxidant proteins mediating root nodule symbiosis.IMPORTANCE Glutaredoxin catalyzes glutathionylation/deglutathionylation reactions, protects SH-groups from oxidation and restores functionally active thiols. Three glutaredoxins exist in R. leguminosarum and their properties were investigated in free-living bacteria and during nitrogen-fixing symbiosis. All the glutaredoxins were necessary for oxidative stress defense. Dithiol GrxA affects nodulation and nitrogen fixation of bacteroids by altering deglutathionylation reactions, monothiol GrxB is involved in symbiotic nitrogen fixation by regulating Fe-S cluster biogenesis, and GrxC may participate in symbiosis by an unknown mechanism. Proteome analysis provides clues to explain the differences between the grx triple mutant and wild-type nodules.
Collapse
|
18
|
Rodríguez S, Correa-Galeote D, Sánchez-Pérez M, Ramírez M, Isidra-Arellano MC, Reyero-Saavedra MDR, Zamorano-Sánchez D, Hernández G, Valdés-López O, Girard L. A Novel OmpR-Type Response Regulator Controls Multiple Stages of the Rhizobium etli - Phaseolus vulgaris N 2-Fixing Symbiosis. Front Microbiol 2021; 11:615775. [PMID: 33384681 PMCID: PMC7769827 DOI: 10.3389/fmicb.2020.615775] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 11/26/2020] [Indexed: 11/22/2022] Open
Abstract
OmpR, is one of the best characterized response regulators families, which includes transcriptional regulators with a variety of physiological roles including the control of symbiotic nitrogen fixation (SNF). The Rhizobium etli CE3 genome encodes 18 OmpR-type regulators; the function of the majority of these regulators during the SNF in common bean, remains elusive. In this work, we demonstrated that a R. etli mutant strain lacking the OmpR-type regulator RetPC57 (ΔRetPC57), formed less nodules when used as inoculum for common bean. Furthermore, we observed reduced expression level of bacterial genes involved in Nod Factors production (nodA and nodB) and of plant early-nodulation genes (NSP2, NIN, NF-YA and ENOD40), in plants inoculated with ΔRetPC57. RetPC57 also contributes to the appropriate expression of genes which products are part of the multidrug efflux pumps family (MDR). Interestingly, nodules elicited by ΔRetPC57 showed increased expression of genes relevant for Carbon/Nitrogen nodule metabolism (PEPC and GOGAT) and ΔRetPC57 bacteroids showed higher nitrogen fixation activity as well as increased expression of key genes directly involved in SNF (hfixL, fixKf, fnrN, fixN, nifA and nifH). Taken together, our data show that the previously uncharacterized regulator RetPC57 is a key player in the development of the R. etli - P. vulgaris symbiosis.
Collapse
Affiliation(s)
- Susana Rodríguez
- Programa de Biología de Sistemas y Biología Sintética, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - David Correa-Galeote
- Programa de Biología de Sistemas y Biología Sintética, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Mishael Sánchez-Pérez
- Programa de Biología de Sistemas y Biología Sintética, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico.,Programa de Genómica Computacional, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Mario Ramírez
- Programa de Genómica Funcional de Eucariontes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Mariel C Isidra-Arellano
- Laboratorio de Genómica Funcional de Leguminosas, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla de Baz, Mexico
| | - María Del Rocío Reyero-Saavedra
- Laboratorio de Genómica Funcional de Leguminosas, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla de Baz, Mexico
| | - David Zamorano-Sánchez
- Programa de Biología de Sistemas y Biología Sintética, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Georgina Hernández
- Programa de Genómica Funcional de Eucariontes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Oswaldo Valdés-López
- Laboratorio de Genómica Funcional de Leguminosas, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla de Baz, Mexico
| | - Lourdes Girard
- Programa de Biología de Sistemas y Biología Sintética, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| |
Collapse
|
19
|
Aroney STN, Poole PS, Sánchez-Cañizares C. Rhizobial Chemotaxis and Motility Systems at Work in the Soil. FRONTIERS IN PLANT SCIENCE 2021; 12:725338. [PMID: 34512702 PMCID: PMC8429497 DOI: 10.3389/fpls.2021.725338] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/06/2021] [Indexed: 05/17/2023]
Abstract
Bacteria navigate their way often as individual cells through their chemical and biological environment in aqueous medium or across solid surfaces. They swim when starved or in response to physical and chemical stimuli. Flagella-driven chemotaxis in bacteria has emerged as a paradigm for both signal transduction and cellular decision-making. By altering motility, bacteria swim toward nutrient-rich environments, movement modulated by their chemotaxis systems with the addition of pili for surface movement. The numbers and types of chemoreceptors reflect the bacterial niche and lifestyle, with those adapted to complex environments having diverse metabolic capabilities, encoding far more chemoreceptors in their genomes. The Alpha-proteobacteria typify the latter case, with soil bacteria such as rhizobia, endosymbionts of legume plants, where motility and chemotaxis are essential for competitive symbiosis initiation, among other processes. This review describes the current knowledge of motility and chemotaxis in six model soil bacteria: Sinorhizobium meliloti, Agrobacterium fabacearum, Rhizobium leguminosarum, Azorhizobium caulinodans, Azospirillum brasilense, and Bradyrhizobium diazoefficiens. Although motility and chemotaxis systems have a conserved core, rhizobia possess several modifications that optimize their movements in soil and root surface environments. The soil provides a unique challenge for microbial mobility, since water pathways through particles are not always continuous, especially in drier conditions. The effectiveness of symbiont inoculants in a field context relies on their mobility and dispersal through the soil, often assisted by water percolation or macroorganism movement or networks. Thus, this review summarizes the factors that make it essential to consider and test rhizobial motility and chemotaxis for any potential inoculant.
Collapse
|
20
|
Durán D, Albareda M, García C, Marina AI, Ruiz-Argüeso T, Palacios JM. Proteome Analysis Reveals a Significant Host-Specific Response in Rhizobium leguminosarum bv. viciae Endosymbiotic Cells. Mol Cell Proteomics 2020; 20:100009. [PMID: 33214187 PMCID: PMC7950203 DOI: 10.1074/mcp.ra120.002276] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/15/2020] [Accepted: 11/19/2020] [Indexed: 11/06/2022] Open
Abstract
The Rhizobium-legume symbiosis is a beneficial interaction in which the bacterium converts atmospheric nitrogen into ammonia and delivers it to the plant in exchange for carbon compounds. This symbiosis implies the adaptation of bacteria to live inside host plant cells. In this work, we apply RP-LC-MS/MS and isobaric tags as relative and absolute quantitation techniques to study the proteomic profile of endosymbiotic cells (bacteroids) induced by Rhizobium leguminosarum bv viciae strain UPM791 in legume nodules. Nitrogenase subunits, tricarboxylic acid cycle enzymes, and stress-response proteins are among the most abundant from over 1000 rhizobial proteins identified in pea (Pisum sativum) bacteroids. Comparative analysis of bacteroids induced in pea and in lentil (Lens culinaris) nodules revealed the existence of a significant host-specific differential response affecting dozens of bacterial proteins, including stress-related proteins, transcriptional regulators, and proteins involved in the carbon and nitrogen metabolisms. A mutant affected in one of these proteins, homologous to a GntR-like transcriptional regulator, showed a symbiotic performance significantly impaired in symbiosis with pea but not with lentil plants. Analysis of the proteomes of bacteroids isolated from both hosts also revealed the presence of different sets of plant-derived nodule-specific cysteine-rich peptides, indicating that the endosymbiotic bacteria find a host-specific cocktail of chemical stressors inside the nodule. By studying variations of the bacterial response to different plant cell environments, we will be able to identify specific limitations imposed by the host that might give us clues for the improvement of rhizobial performance.
Collapse
Affiliation(s)
- David Durán
- Centro de Biotecnología y Genómica de Plantas (C.B.G.P.) UPM-INIA, Campus de Montegancedo, Universidad Politécnica de Madrid, Madrid, Spain; Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Madrid, Spain
| | - Marta Albareda
- Centro de Biotecnología y Genómica de Plantas (C.B.G.P.) UPM-INIA, Campus de Montegancedo, Universidad Politécnica de Madrid, Madrid, Spain; Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Madrid, Spain
| | - Carlos García
- Servicio de Proteómica, Centro de Biología Molecular Severo Ochoa (CBMSO), CSIC Campus Cantoblanco, Madrid, Spain
| | - Ana-Isabel Marina
- Servicio de Proteómica, Centro de Biología Molecular Severo Ochoa (CBMSO), CSIC Campus Cantoblanco, Madrid, Spain
| | - Tomás Ruiz-Argüeso
- Centro de Biotecnología y Genómica de Plantas (C.B.G.P.) UPM-INIA, Campus de Montegancedo, Universidad Politécnica de Madrid, Madrid, Spain; Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Madrid, Spain
| | - Jose-Manuel Palacios
- Centro de Biotecnología y Genómica de Plantas (C.B.G.P.) UPM-INIA, Campus de Montegancedo, Universidad Politécnica de Madrid, Madrid, Spain; Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Madrid, Spain.
| |
Collapse
|
21
|
Salehi B, Abu-Reidah IM, Sharopov F, Karazhan N, Sharifi-Rad J, Akram M, Daniyal M, Khan FS, Abbaass W, Zainab R, Carbone K, Fahmy NM, Al-Sayed E, El-Shazly M, Lucarini M, Durazzo A, Santini A, Martorell M, Pezzani R. Vicia plants-A comprehensive review on chemical composition and phytopharmacology. Phytother Res 2020; 35:790-809. [PMID: 32930444 DOI: 10.1002/ptr.6863] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 08/10/2020] [Accepted: 08/13/2020] [Indexed: 12/28/2022]
Abstract
The plants belonging to the genus Vicia are of great interest as a source of many bioactive compounds and micronutrients. A snapshot of their cultivation, habitat, main components, from which essential oils can be obtained, is given. The traditional medicinal uses of Vicia plants are also reported, as well as the wide spectrum of the main biological activities attributed to Vicia plants is discussed regarding potential health beneficial properties, in particular anti-Parkinson, anticholinesterase, antidepressant, anticonvulsant, antimicrobial, cytotoxic, antioxidant, antiinflammatory and antinociceptive, antidiabetic, antihemolytic, anticoagulant, estrogenic, diuretic, antihypoxic activities.
Collapse
Affiliation(s)
- Bahare Salehi
- Noncommunicable Diseases Research Center, Bam University of Medical Sciences, Bam, Iran, Bam, Iran.,Student Research Committee, School of Medicine, Bam University of Medical Sciences, Bam, Iran
| | - Ibrahim M Abu-Reidah
- Department of Environmental Science/Boreal Ecosystem Research Initiative, Memorial University of Newfoundland, Corner Brook, Newfoundland and Labrador, Canada
| | - Farukh Sharopov
- Department of Pharmaceutical Technology, Avicenna Tajik State Medical University, Dushanbe, Tajikistan
| | - Natallia Karazhan
- Department of Pharmacognosy, Pharmaceutical Faculty of the EE VSMU, Vitebsk, Republic of Belarus
| | - Javad Sharifi-Rad
- Phytochemistry Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Muhammad Akram
- Department of Eastern Medicine, Government College University Faisalabad, Faisalabad, Pakistan
| | - Muhammad Daniyal
- TCM and Ethnomedicine Innovation & Development International Laboratory, Innovative Drug Research Institute, School of Pharmacy, Hunan University of Chinese Medicine, Changsha, China
| | - Fahad Said Khan
- Department of Eastern Medicine, University of Poonch, Rawalakot, Pakistan
| | - Wafa Abbaass
- Department of Eastern Medicine, Government College University Faisalabad, Faisalabad, Pakistan
| | - Rida Zainab
- Department of Eastern Medicine, Government College University Faisalabad, Faisalabad, Pakistan
| | - Katya Carbone
- CREA, Research Centre for Olive, Citrus and Tree Fruit, Rome, Italy
| | - Nouran M Fahmy
- Department of Pharmacognosy, Faculty of Pharmacy, Ain-Shams University, Cairo, Egypt
| | - Eman Al-Sayed
- Department of Pharmacognosy, Faculty of Pharmacy, Ain-Shams University, Cairo, Egypt
| | - Mohamed El-Shazly
- Department of Pharmacognosy, Faculty of Pharmacy, Ain-Shams University, Cairo, Egypt.,Department of Pharmaceutical Biology, Faculty of Pharmacy and Biotechnology, German University in Cairo, Cairo, Egypt
| | | | | | - Antonello Santini
- Department of Pharmacy, University of Napoli Federico II, Naples, Italy
| | - Miquel Martorell
- Department of Nutrition and Dietetics, Faculty of Pharmacy, University of Concepcion, Concepcion, Chile.,Universidad de Concepción, Unidad de Desarrollo Tecnológico, UDT, Concepcion, Chile
| | - Raffaele Pezzani
- Department of Medicine (DIMED), OU Endocrinology, University of Padova, Padova, Italy.,AIROB, Associazione Italiana per la Ricerca Oncologica di Base, Padova, Italy
| |
Collapse
|
22
|
Abstract
By analyzing successive lifestyle stages of a model Rhizobium-legume symbiosis using mariner-based transposon insertion sequencing (INSeq), we have defined the genes required for rhizosphere growth, root colonization, bacterial infection, N2-fixing bacteroids, and release from legume (pea) nodules. While only 27 genes are annotated as nif and fix in Rhizobium leguminosarum, we show 603 genetic regions (593 genes, 5 transfer RNAs, and 5 RNA features) are required for the competitive ability to nodulate pea and fix N2 Of these, 146 are common to rhizosphere growth through to bacteroids. This large number of genes, defined as rhizosphere-progressive, highlights how critical successful competition in the rhizosphere is to subsequent infection and nodulation. As expected, there is also a large group (211) specific for nodule bacteria and bacteroid function. Nodule infection and bacteroid formation require genes for motility, cell envelope restructuring, nodulation signaling, N2 fixation, and metabolic adaptation. Metabolic adaptation includes urea, erythritol and aldehyde metabolism, glycogen synthesis, dicarboxylate metabolism, and glutamine synthesis (GlnII). There are 17 separate lifestyle adaptations specific to rhizosphere growth and 23 to root colonization, distinct from infection and nodule formation. These results dramatically highlight the importance of competition at multiple stages of a Rhizobium-legume symbiosis.
Collapse
|
23
|
Zou Q, Luo S, Wu H, He D, Li X, Cheng G. A GMC Oxidoreductase GmcA Is Required for Symbiotic Nitrogen Fixation in Rhizobium leguminosarum bv. viciae. Front Microbiol 2020; 11:394. [PMID: 32265862 PMCID: PMC7105596 DOI: 10.3389/fmicb.2020.00394] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/26/2020] [Indexed: 11/13/2022] Open
Abstract
GmcA is a FAD-containing enzyme belonging to the GMC (glucose-methanol-choline oxidase) family of oxidoreductases. A mutation in the Rhizobium leguminosarum gmcA gene was generated by homologous recombination. The mutation in gmcA did not affect the growth of R. leguminosarum, but it displayed decreased antioxidative capacity at H2O2 conditions higher than 5 mM. The gmcA mutant strain displayed no difference of glutathione reductase activity, but significantly lower level of the glutathione peroxidase activity than the wild type. Although the gmcA mutant was able to induce the formation of nodules, the symbiotic ability was severely impaired, which led to an abnormal nodulation phenotype coupled to a 30% reduction in the nitrogen fixation capacity. The observation on ultrastructure of 4-week pea nodules showed that the mutant bacteroids tended to start senescence earlier and accumulate poly-β-hydroxybutyrate (PHB) granules. In addition, the gmcA mutant was severely impaired in rhizosphere colonization. Real-time quantitative PCR showed that the gmcA gene expression was significantly up-regulated in all the detected stages of nodule development, and statistically significant decreases in the expression of the redoxin genes katG, katE, and ohrB were found in gmcA mutant bacteroids. LC-MS/MS analysis quantitative proteomics techniques were employed to compare differential gmcA mutant root bacteroids in response to the wild type infection. Sixty differentially expressed proteins were identified including 33 up-regulated and 27 down-regulated proteins. By sorting the identified proteins according to metabolic function, 15 proteins were transporter protein, 12 proteins were related to stress response and virulence, and 9 proteins were related to transcription factor activity. Moreover, nine proteins related to amino acid metabolism were over-expressed.
Collapse
Affiliation(s)
- Qian Zou
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Sha Luo
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Hetao Wu
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Donglan He
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Xiaohua Li
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Guojun Cheng
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, China
| |
Collapse
|
24
|
Metabolic Analyses of Nitrogen Fixation in the Soybean Microsymbiont Sinorhizobium fredii Using Constraint-Based Modeling. mSystems 2020; 5:5/1/e00516-19. [PMID: 32071157 PMCID: PMC7029217 DOI: 10.1128/msystems.00516-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Nitrogen is the most limiting macronutrient for plant growth, and rhizobia are important bacteria for agriculture because they can fix atmospheric nitrogen and make it available to legumes through the establishment of a symbiotic relationship with their host plants. In this work, we studied the nitrogen fixation process in the microsymbiont Sinorhizobium fredii at the genome level. A metabolic model was built using genome annotation and literature to reconstruct the symbiotic form of S. fredii. Genes controlling the nitrogen fixation process were identified by simulating gene knockouts. Additionally, the nitrogen-fixing capacities of S. fredii CCBAU45436 in symbiosis with cultivated and wild soybeans were evaluated. The predictions suggested an outperformance of S. fredii with cultivated soybean, consistent with published experimental evidence. The reconstruction presented here will help to understand and improve nitrogen fixation capabilities of S. fredii and will be beneficial for agriculture by reducing the reliance on fertilizer applications. Rhizobia are soil bacteria able to establish symbiosis with diverse host plants. Specifically, Sinorhizobium fredii is a soil bacterium that forms nitrogen-fixing root nodules in diverse legumes, including soybean. The strain S. fredii CCBAU45436 is a dominant sublineage of S. fredii that nodulates soybeans in alkaline-saline soils in the Huang-Huai-Hai Plain region of China. Here, we present a manually curated metabolic model of the symbiotic form of Sinorhizobium fredii CCBAU45436. A symbiosis reaction was defined to describe the specific soybean-microsymbiont association. The performance and quality of the reconstruction had a 70% score when assessed using a standardized genome-scale metabolic model test suite. The model was used to evaluate in silico single-gene knockouts to determine the genes controlling the nitrogen fixation process. One hundred forty-one of 541 genes (26%) were found to influence the symbiotic process, wherein 121 genes were predicted as essential and 20 others as having a partial effect. Transcriptomic profiles of CCBAU45436 were used to evaluate the nitrogen fixation capacity in cultivated versus in wild soybean inoculated with the microsymbiont. The model quantified the nitrogen fixation activities of the strain in these two hosts and predicted a higher nitrogen fixation capacity in cultivated soybean. Our results are consistent with published data demonstrating larger amounts of ureides and total nitrogen in cultivated soybean than in wild soybean. This work presents the first metabolic network reconstruction of S. fredii as an example of a useful tool for exploring the potential benefits of microsymbionts to sustainable agriculture and the ecosystem. IMPORTANCE Nitrogen is the most limiting macronutrient for plant growth, and rhizobia are important bacteria for agriculture because they can fix atmospheric nitrogen and make it available to legumes through the establishment of a symbiotic relationship with their host plants. In this work, we studied the nitrogen fixation process in the microsymbiont Sinorhizobium fredii at the genome level. A metabolic model was built using genome annotation and literature to reconstruct the symbiotic form of S. fredii. Genes controlling the nitrogen fixation process were identified by simulating gene knockouts. Additionally, the nitrogen-fixing capacities of S. fredii CCBAU45436 in symbiosis with cultivated and wild soybeans were evaluated. The predictions suggested an outperformance of S. fredii with cultivated soybean, consistent with published experimental evidence. The reconstruction presented here will help to understand and improve nitrogen fixation capabilities of S. fredii and will be beneficial for agriculture by reducing the reliance on fertilizer applications.
Collapse
|
25
|
Mergaert P, Kereszt A, Kondorosi E. Gene Expression in Nitrogen-Fixing Symbiotic Nodule Cells in Medicago truncatula and Other Nodulating Plants. THE PLANT CELL 2020; 32:42-68. [PMID: 31712407 PMCID: PMC6961632 DOI: 10.1105/tpc.19.00494] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 11/08/2019] [Indexed: 05/06/2023]
Abstract
Root nodules formed by plants of the nitrogen-fixing clade (NFC) are symbiotic organs that function in the maintenance and metabolic integration of large populations of nitrogen-fixing bacteria. These organs feature unique characteristics and processes, including their tissue organization, the presence of specific infection structures called infection threads, endocytotic uptake of bacteria, symbiotic cells carrying thousands of intracellular bacteria without signs of immune responses, and the integration of symbiont and host metabolism. The early stages of nodulation are governed by a few well-defined functions, which together constitute the common symbiosis-signaling pathway (CSSP). The CSSP activates a set of transcription factors (TFs) that orchestrate nodule organogenesis and infection. The later stages of nodule development require the activation of hundreds to thousands of genes, mostly expressed in symbiotic cells. Many of these genes are only active in symbiotic cells, reflecting the unique nature of nodules as plant structures. Although how the nodule-specific transcriptome is activated and connected to early CSSP-signaling is poorly understood, candidate TFs have been identified using transcriptomic approaches, and the importance of epigenetic and chromatin-based regulation has been demonstrated. We discuss how gene regulation analyses have advanced our understanding of nodule organogenesis, the functioning of symbiotic cells, and the evolution of symbiosis in the NFC.
Collapse
Affiliation(s)
- Peter Mergaert
- Institute for Integrative Biology of the Cell, UMR 9198, CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Attila Kereszt
- Institute of Plant Biology, Biological Research Centre, 6726 Szeged, Hungary
| | - Eva Kondorosi
- Institute of Plant Biology, Biological Research Centre, 6726 Szeged, Hungary
| |
Collapse
|
26
|
Cherni AE, Perret X. Deletion of rRNA Operons of Sinorhizobium fredii Strain NGR234 and Impact on Symbiosis With Legumes. Front Microbiol 2019; 10:154. [PMID: 30814981 PMCID: PMC6381291 DOI: 10.3389/fmicb.2019.00154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 01/22/2019] [Indexed: 01/08/2023] Open
Abstract
During their lifecycle, from free-living soil bacteria to endosymbiotic nitrogen-fixing bacteroids of legumes, rhizobia must colonize, and cope with environments where nutrient concentrations and compositions vary greatly. Bacterial colonization of legume rhizospheres and of root surfaces is subject to a fierce competition for plant exudates. By contrast root nodules offer to rhizobia sheltered nutrient-rich environments within which the cells that successfully propagated via infection threads can rapidly multiply. To explore the effects on symbiosis of a slower rhizobia growth and metabolism, we deleted one or two copies of the three functional rRNA operons of the promiscuous Sinorhizobium fredii strain NGR234 and examined the impact of these mutations on free-living and symbiotic lifestyles. Strains with two functional rRNA operons (NGRΔrRNA1 and NGRΔrRNA3) grew almost as rapidly as NGR234, and NGRΔrRNA1 was as proficient as the parent strain on all of the five legume species tested. By contrast, the NGRΔrRNA1,3 double mutant, which carried a single rRNA operon and grew significantly slower than NGR234, had a reduced symbiotic proficiency on Cajanus cajan, Macroptilium atropurpureum, Tephrosia vogelii, and Vigna unguiculata. In addition, while NGRΔrRNA1 and NGR234 equally competed for nodulation of V. unguiculata, strain NGRΔrRNA1,3 was clearly outcompeted by wild-type. Surprisingly, on Leucaena leucocephala, NGRΔrRNA1,3 was the most proficient strain and competed equally NGR234 for nodule occupation. Together, these results indicate that for strains with otherwise identical repertoires of symbiotic genes, a faster growth on roots and/or inside plant tissues may contribute to secure access to nodules of some hosts. By contrast, other legumes such as L. leucocephala appear as less selective and capable of providing symbiotic environments susceptible to accommodate strains with a broader spectrum of competences.
Collapse
Affiliation(s)
- Ala Eddine Cherni
- Microbiology Unit, Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva, Switzerland
| | - Xavier Perret
- Microbiology Unit, Department of Botany and Plant Biology, Sciences III, University of Geneva, Geneva, Switzerland
| |
Collapse
|
27
|
Green RT, East AK, Karunakaran R, Downie JA, Poole PS. Transcriptomic analysis of Rhizobium leguminosarum bacteroids in determinate and indeterminate nodules. Microb Genom 2019; 5:e000254. [PMID: 30777812 PMCID: PMC6421345 DOI: 10.1099/mgen.0.000254] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 01/15/2019] [Indexed: 01/25/2023] Open
Abstract
Two common classes of nitrogen-fixing legume root nodules are those that have determinate or indeterminate meristems, as in Phaseolus bean and pea, respectively. In indeterminate nodules, rhizobia terminally differentiate into bacteroids with endoreduplicated genomes, whereas bacteroids from determinate nodules are less differentiated and can regrow. We used RNA sequencing to compare bacteroid gene expression in determinate and indeterminate nodules using two Rhizobium leguminosarum strains whose genomes differ due to replacement of the symbiosis (Sym) plasmid pRP2 (strain Rlp4292) with pRL1 (strain RlvA34), thereby switching symbiosis hosts from Phaseolus bean (determinate nodules) to pea (indeterminate nodules). Both bacteroid types have gene expression patterns typical of a stringent response, a stressful environment and catabolism of dicarboxylates, formate, amino acids and quaternary amines. Gene expression patterns were indicative that bean bacteroids were more limited for phosphate, sulphate and iron than pea bacteroids. Bean bacteroids had higher levels of expression of genes whose products are predicted to be associated with metabolite detoxification or export. Pea bacteroids had increased expression of genes associated with DNA replication, membrane synthesis and the TCA (tricarboxylic acid) cycle. Analysis of bacteroid-specific transporter genes was indicative of distinct differences in sugars and other compounds in the two nodule environments. Cell division genes were down-regulated in pea but not bean bacteroids, while DNA synthesis was increased in pea bacteroids. This is consistent with endoreduplication of pea bacteroids and their failure to regrow once nodules senesce.
Collapse
Affiliation(s)
- R. T. Green
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - A. K. East
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - R. Karunakaran
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - J. A. Downie
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - P. S. Poole
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| |
Collapse
|
28
|
diCenzo GC, Zamani M, Checcucci A, Fondi M, Griffitts JS, Finan TM, Mengoni A. Multidisciplinary approaches for studying rhizobium–legume symbioses. Can J Microbiol 2019; 65:1-33. [DOI: 10.1139/cjm-2018-0377] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The rhizobium–legume symbiosis is a major source of fixed nitrogen (ammonia) in the biosphere. The potential for this process to increase agricultural yield while reducing the reliance on nitrogen-based fertilizers has generated interest in understanding and manipulating this process. For decades, rhizobium research has benefited from the use of leading techniques from a very broad set of fields, including population genetics, molecular genetics, genomics, and systems biology. In this review, we summarize many of the research strategies that have been employed in the study of rhizobia and the unique knowledge gained from these diverse tools, with a focus on genome- and systems-level approaches. We then describe ongoing synthetic biology approaches aimed at improving existing symbioses or engineering completely new symbiotic interactions. The review concludes with our perspective of the future directions and challenges of the field, with an emphasis on how the application of a multidisciplinary approach and the development of new methods will be necessary to ensure successful biotechnological manipulation of the symbiosis.
Collapse
Affiliation(s)
- George C. diCenzo
- Department of Biology, University of Florence, Sesto Fiorentino, FI 50019, Italy
| | - Maryam Zamani
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Alice Checcucci
- Department of Biology, University of Florence, Sesto Fiorentino, FI 50019, Italy
| | - Marco Fondi
- Department of Biology, University of Florence, Sesto Fiorentino, FI 50019, Italy
| | - Joel S. Griffitts
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT 84602, USA
| | - Turlough M. Finan
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Alessio Mengoni
- Department of Biology, University of Florence, Sesto Fiorentino, FI 50019, Italy
| |
Collapse
|
29
|
Stambulska UY, Bayliak MM. Legume-Rhizobium Symbiosis: Secondary Metabolites, Free Radical Processes, and Effects of Heavy Metals. BIOACTIVE MOLECULES IN FOOD 2019. [DOI: 10.1007/978-3-319-76887-8_43-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
30
|
Liu YH, Wang ET, Jiao YS, Tian CF, Wang L, Wang ZJ, Guan JJ, Singh RP, Chen WX, Chen WF. Symbiotic characteristics of Bradyrhizobium diazoefficiens USDA 110 mutants associated with shrubby sophora (Sophora flavescens) and soybean (Glycine max). Microbiol Res 2018; 214:19-27. [PMID: 30031478 DOI: 10.1016/j.micres.2018.05.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 04/09/2018] [Accepted: 05/14/2018] [Indexed: 01/20/2023]
Abstract
Site-specific insertion plasmid pVO155 was used to knockout the genes involved in the alternation of host range of strain Bradyrhizobium diazoefficiens USDA 110 from its original determinate-nodule-forming host soybean (Glycine max), to promiscuous and indeterminate-nodule-forming shrubby legume sophora (Sophora flavescens). Symbiotic phenotypes of these mutants inoculated to these two legumes, were compared to those infected by wild-type strain USDA 110. Six genes of the total fourteen Tn5 transposon mutated genes were broken using the pVO155 plasmid. Both Tn5 and pVO155-inserted mutants could nodulate S. flavescens with different morphologies of low-efficient indeterminate nodules. One to several rod or irregular bacteroids, containing different contents of poly-β-hydroxybutyrate or polyphosphate were found within the symbiosomes in nodulated cells of S. flavescens infected by the pVO155-inserted mutants. Moreover, none of bacteroids were observed in the pseudonodules of S. flavescens, infected by wild-type strain USDA 110. These mutants had the nodulation ability with soybean but the symbiotic efficiency reduced to diverse extents. These findings enlighten the complicated interactions between rhizobia and legumes, i. e., mutation of genes involved in metabolic pathways, transporters, chemotaxis and mobility could alter the rhizobial entry and development of the bacteroid inside the nodules of a new host legume.
Collapse
Affiliation(s)
- Yuan Hui Liu
- State Key Laboratory of Agrobiotechnology, Beijing 100193, China; College of Biological Sciences and Rhizobium Research Center, China Agricultural University, Beijing 100193, China
| | - En Tao Wang
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México D. F. 11340, México
| | - Yin Shan Jiao
- State Key Laboratory of Agrobiotechnology, Beijing 100193, China; College of Biological Sciences and Rhizobium Research Center, China Agricultural University, Beijing 100193, China
| | - Chang Fu Tian
- State Key Laboratory of Agrobiotechnology, Beijing 100193, China; College of Biological Sciences and Rhizobium Research Center, China Agricultural University, Beijing 100193, China
| | - Lei Wang
- State Key Laboratory of Agrobiotechnology, Beijing 100193, China; College of Biological Sciences and Rhizobium Research Center, China Agricultural University, Beijing 100193, China
| | - Zi Jian Wang
- State Key Laboratory of Agrobiotechnology, Beijing 100193, China; College of Biological Sciences and Rhizobium Research Center, China Agricultural University, Beijing 100193, China
| | - Jia Jing Guan
- State Key Laboratory of Agrobiotechnology, Beijing 100193, China; College of Biological Sciences and Rhizobium Research Center, China Agricultural University, Beijing 100193, China
| | - Raghvendra Pratap Singh
- Microbial Genomics Laboratory, National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan, Uttar Pradesh 275101, India
| | - Wen Xin Chen
- State Key Laboratory of Agrobiotechnology, Beijing 100193, China; College of Biological Sciences and Rhizobium Research Center, China Agricultural University, Beijing 100193, China
| | - Wen Feng Chen
- State Key Laboratory of Agrobiotechnology, Beijing 100193, China; College of Biological Sciences and Rhizobium Research Center, China Agricultural University, Beijing 100193, China.
| |
Collapse
|
31
|
Lamouche F, Gully D, Chaumeret A, Nouwen N, Verly C, Pierre O, Sciallano C, Fardoux J, Jeudy C, Szücs A, Mondy S, Salon C, Nagy I, Kereszt A, Dessaux Y, Giraud E, Mergaert P, Alunni B. Transcriptomic dissection of Bradyrhizobium sp. strain ORS285 in symbiosis with Aeschynomene spp. inducing different bacteroid morphotypes with contrasted symbiotic efficiency. Environ Microbiol 2018; 21:3244-3258. [PMID: 29921018 DOI: 10.1111/1462-2920.14292] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 05/18/2017] [Accepted: 05/19/2017] [Indexed: 11/29/2022]
Abstract
To circumvent the paucity of nitrogen sources in the soil legume plants establish a symbiotic interaction with nitrogen-fixing soil bacteria called rhizobia. During symbiosis, the plants form root organs called nodules, where bacteria are housed intracellularly and become active nitrogen fixers known as bacteroids. Depending on their host plant, bacteroids can adopt different morphotypes, being either unmodified (U), elongated (E) or spherical (S). E- and S-type bacteroids undergo a terminal differentiation leading to irreversible morphological changes and DNA endoreduplication. Previous studies suggest that differentiated bacteroids display an increased symbiotic efficiency (E > U and S > U). In this study, we used a combination of Aeschynomene species inducing E- or S-type bacteroids in symbiosis with Bradyrhizobium sp. ORS285 to show that S-type bacteroids present a better symbiotic efficiency than E-type bacteroids. We performed a transcriptomic analysis on E- and S-type bacteroids formed by Aeschynomene afraspera and Aeschynomene indica nodules and identified the bacterial functions activated in bacteroids and specific to each bacteroid type. Extending the expression analysis in E- and S-type bacteroids in other Aeschynomene species by qRT-PCR on selected genes from the transcriptome analysis narrowed down the set of bacteroid morphotype-specific genes. Functional analysis of a selected subset of 31 bacteroid-induced or morphotype-specific genes revealed no symbiotic phenotypes in the mutants. This highlights the robustness of the symbiotic program but could also indicate that the bacterial response to the plant environment is partially anticipatory or even maladaptive. Our analysis confirms the correlation between differentiation and efficiency of the bacteroids and provides a framework for the identification of bacterial functions that affect the efficiency of bacteroids.© 2018 Society for Applied Microbiology and John Wiley & Sons Ltd.
Collapse
Affiliation(s)
- Florian Lamouche
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
| | - Djamel Gully
- Laboratoire des Symbioses Tropicales et Méditerranéennes, Institut pour la Recherche et le Développement, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, Montpellier, 34398, France
| | - Anaïs Chaumeret
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
| | - Nico Nouwen
- Laboratoire des Symbioses Tropicales et Méditerranéennes, Institut pour la Recherche et le Développement, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, Montpellier, 34398, France
| | - Camille Verly
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
| | - Olivier Pierre
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
| | - Coline Sciallano
- Laboratoire des Symbioses Tropicales et Méditerranéennes, Institut pour la Recherche et le Développement, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, Montpellier, 34398, France
| | - Joël Fardoux
- Laboratoire des Symbioses Tropicales et Méditerranéennes, Institut pour la Recherche et le Développement, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, Montpellier, 34398, France
| | - Christian Jeudy
- Agroécologie, AgroSup Dijon, INRA, Université Bourgogne Franche-Comté, Dijon, 21065, France
| | - Attila Szücs
- Biological Research Centre, Hungarian Academy of Sciences, Szeged, 6726, Hungary
| | - Samuel Mondy
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
| | - Christophe Salon
- Agroécologie, AgroSup Dijon, INRA, Université Bourgogne Franche-Comté, Dijon, 21065, France
| | - István Nagy
- Biological Research Centre, Hungarian Academy of Sciences, Szeged, 6726, Hungary
- Seqomics Biotechnology Ltd, Mórahalom, 6782, Hungary
| | - Attila Kereszt
- Biological Research Centre, Hungarian Academy of Sciences, Szeged, 6726, Hungary
- Seqomics Biotechnology Ltd, Mórahalom, 6782, Hungary
| | - Yves Dessaux
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
| | - Eric Giraud
- Laboratoire des Symbioses Tropicales et Méditerranéennes, Institut pour la Recherche et le Développement, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, Montpellier, 34398, France
| | - Peter Mergaert
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
| | - Benoit Alunni
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
| |
Collapse
|
32
|
Functional Genomics Approaches to Studying Symbioses between Legumes and Nitrogen-Fixing Rhizobia. High Throughput 2018; 7:ht7020015. [PMID: 29783718 PMCID: PMC6023288 DOI: 10.3390/ht7020015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 05/13/2018] [Accepted: 05/16/2018] [Indexed: 01/24/2023] Open
Abstract
Biological nitrogen fixation gives legumes a pronounced growth advantage in nitrogen-deprived soils and is of considerable ecological and economic interest. In exchange for reduced atmospheric nitrogen, typically given to the plant in the form of amides or ureides, the legume provides nitrogen-fixing rhizobia with nutrients and highly specialised root structures called nodules. To elucidate the molecular basis underlying physiological adaptations on a genome-wide scale, functional genomics approaches, such as transcriptomics, proteomics, and metabolomics, have been used. This review presents an overview of the different functional genomics approaches that have been performed on rhizobial symbiosis, with a focus on studies investigating the molecular mechanisms used by the bacterial partner to interact with the legume. While rhizobia belonging to the alpha-proteobacterial group (alpha-rhizobia) have been well studied, few studies to date have investigated this process in beta-proteobacteria (beta-rhizobia).
Collapse
|
33
|
Calatrava-Morales N, McIntosh M, Soto MJ. Regulation Mediated by N-Acyl Homoserine Lactone Quorum Sensing Signals in the Rhizobium-Legume Symbiosis. Genes (Basel) 2018; 9:genes9050263. [PMID: 29783703 PMCID: PMC5977203 DOI: 10.3390/genes9050263] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 05/15/2018] [Accepted: 05/15/2018] [Indexed: 02/06/2023] Open
Abstract
Soil-dwelling bacteria collectively referred to as rhizobia synthesize and perceive N-acyl-homoserine lactone (AHL) signals to regulate gene expression in a population density-dependent manner. AHL-mediated signaling in these bacteria regulates several functions which are important for the establishment of nitrogen-fixing symbiosis with legume plants. Moreover, rhizobial AHL act as interkingdom signals triggering plant responses that impact the plant-bacteria interaction. Both the regulatory mechanisms that control AHL synthesis in rhizobia and the set of bacterial genes and associated traits under quorum sensing (QS) control vary greatly among the rhizobial species. In this article, we focus on the well-known QS system of the alfalfa symbiont Sinorhizobium(Ensifer)meliloti. Bacterial genes, environmental factors and transcriptional and posttranscriptional regulatory mechanisms that control AHL production in this Rhizobium, as well as the effects of the signaling molecule on bacterial phenotypes and plant responses will be reviewed. Current knowledge of S. meliloti QS will be compared with that of other rhizobia. Finally, participation of the legume host in QS by interfering with rhizobial AHL perception through the production of molecular mimics will also be addressed.
Collapse
Affiliation(s)
- Nieves Calatrava-Morales
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC; Granada 18008, Spain.
| | - Matthew McIntosh
- Institut für Mikrobiologie und Molekularbiologie, Universität Giessen, 35392 Giessen, Germany.
| | - María J Soto
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC; Granada 18008, Spain.
| |
Collapse
|
34
|
Lardi M, Liu Y, Giudice G, Ahrens CH, Zamboni N, Pessi G. Metabolomics and Transcriptomics Identify Multiple Downstream Targets of Paraburkholderia phymatum σ 54 During Symbiosis with Phaseolus vulgaris. Int J Mol Sci 2018; 19:ijms19041049. [PMID: 29614780 PMCID: PMC5979394 DOI: 10.3390/ijms19041049] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 03/28/2018] [Accepted: 03/28/2018] [Indexed: 12/20/2022] Open
Abstract
RpoN (or σ54) is the key sigma factor for the regulation of transcription of nitrogen fixation genes in diazotrophic bacteria, which include α- and β-rhizobia. Our previous studies showed that an rpoN mutant of the β-rhizobial strain Paraburkholderia phymatum STM815T formed root nodules on Phaseolus vulgaris cv. Negro jamapa, which were unable to reduce atmospheric nitrogen into ammonia. In an effort to further characterize the RpoN regulon of P. phymatum, transcriptomics was combined with a powerful metabolomics approach. The metabolome of P. vulgaris root nodules infected by a P. phymatumrpoN Fix− mutant revealed statistically significant metabolic changes compared to wild-type Fix+ nodules, including reduced amounts of chorismate and elevated levels of flavonoids. A transcriptome analysis on Fix− and Fix+ nodules—combined with a search for RpoN binding sequences in promoter regions of regulated genes—confirmed the expected control of σ54 on nitrogen fixation genes in nodules. The transcriptomic data also allowed us to identify additional target genes, whose differential expression was able to explain the observed metabolite changes in numerous cases. Moreover, the genes encoding the two-component regulatory system NtrBC were downregulated in root nodules induced by the rpoN mutant, and contained a putative RpoN binding motif in their promoter region, suggesting direct regulation. The construction and characterization of an ntrB mutant strain revealed impaired nitrogen assimilation in free-living conditions, as well as a noticeable symbiotic phenotype, as fewer but heavier nodules were formed on P. vulgaris roots.
Collapse
Affiliation(s)
- Martina Lardi
- Department of Plant and Microbial Biology, University of Zurich, CH-8057 Zurich, Switzerland.
| | - Yilei Liu
- Department of Plant and Microbial Biology, University of Zurich, CH-8057 Zurich, Switzerland.
| | - Gaetano Giudice
- Department of Plant and Microbial Biology, University of Zurich, CH-8057 Zurich, Switzerland.
| | - Christian H Ahrens
- Agroscope, Research Group Molecular Diagnostics, Genomics and Bioinformatics & Swiss Institute of Bioinformatics (SIB), CH-8820 Wädenswil, Switzerland.
| | - Nicola Zamboni
- Institute of Molecular Systems Biology, ETH Zurich, CH-8093 Zurich, Switzerland.
| | - Gabriella Pessi
- Department of Plant and Microbial Biology, University of Zurich, CH-8057 Zurich, Switzerland.
| |
Collapse
|
35
|
Chromium(VI) Toxicity in Legume Plants: Modulation Effects of Rhizobial Symbiosis. BIOMED RESEARCH INTERNATIONAL 2018; 2018:8031213. [PMID: 29662899 PMCID: PMC5832134 DOI: 10.1155/2018/8031213] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 12/31/2017] [Indexed: 11/18/2022]
Abstract
Most legume species have the ability to establish a symbiotic relationship with soil nitrogen-fixing rhizobacteria that promote plant growth and productivity. There is an increasing evidence of reactive oxygen species (ROS) important role in formation of legume-rhizobium symbiosis and nodule functioning. Environmental pollutants such as chromium compounds can cause damage to rhizobia, legumes, and their symbiosis. In plants, toxic effects of chromium(VI) compounds are associated with the increased production of ROS and oxidative stress development as well as with inhibition of pigment synthesis and modification of virtually all cellular components. These metabolic changes result in inhibition of seed germination and seedling development as well as reduction of plant biomass and crop yield. However, if plants establish symbiosis with rhizobia, heavy metals are accumulated preferentially in nodules decreasing the toxicity of metals to the host plant. This review summarizes data on toxic effects of chromium on legume plants and legume-rhizobium symbiosis. In addition, we discussed the role of oxidative stress in both chromium toxicity and formation of rhizobial symbiosis and use of nodule bacteria for minimizing toxic effects of chromium on plants.
Collapse
|
36
|
Abstract
Rhizobia are some of the best-studied plant microbiota. These oligotrophic Alphaproteobacteria or Betaproteobacteria form symbioses with their legume hosts. Rhizobia must exist in soil and compete with other members of the microbiota before infecting legumes and forming N2-fixing bacteroids. These dramatic lifestyle and developmental changes are underpinned by large genomes and even more complex pan-genomes, which encompass the whole population and are subject to rapid genetic exchange. The ability to respond to plant signals and chemoattractants and to colonize nutrient-rich roots are crucial for the competitive success of these bacteria. The availability of a large body of genomic, physiological, biochemical and ecological studies makes rhizobia unique models for investigating community interactions and plant colonization.
Collapse
|
37
|
Transcriptomic Studies of the Effect of nod Gene-Inducing Molecules in Rhizobia: Different Weapons, One Purpose. Genes (Basel) 2017; 9:genes9010001. [PMID: 29267254 PMCID: PMC5793154 DOI: 10.3390/genes9010001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 12/07/2017] [Accepted: 12/15/2017] [Indexed: 12/16/2022] Open
Abstract
Simultaneous quantification of transcripts of the whole bacterial genome allows the analysis of the global transcriptional response under changing conditions. RNA-seq and microarrays are the most used techniques to measure these transcriptomic changes, and both complement each other in transcriptome profiling. In this review, we exhaustively compiled the symbiosis-related transcriptomic reports (microarrays and RNA sequencing) carried out hitherto in rhizobia. This review is specially focused on transcriptomic changes that takes place when five rhizobial species, Bradyrhizobium japonicum (=diazoefficiens) USDA 110, Rhizobium leguminosarum biovar viciae 3841, Rhizobium tropici CIAT 899, Sinorhizobium (=Ensifer) meliloti 1021 and S. fredii HH103, recognize inducing flavonoids, plant-exuded phenolic compounds that activate the biosynthesis and export of Nod factors (NF) in all analysed rhizobia. Interestingly, our global transcriptomic comparison also indicates that each rhizobial species possesses its own arsenal of molecular weapons accompanying the set of NF in order to establish a successful interaction with host legumes.
Collapse
|
38
|
Hood G, Ramachandran V, East AK, Downie JA, Poole PS. Manganese transport is essential for N 2 -fixation by Rhizobium leguminosarum in bacteroids from galegoid but not phaseoloid nodules. Environ Microbiol 2017; 19:2715-2726. [PMID: 28447383 PMCID: PMC5575495 DOI: 10.1111/1462-2920.13773] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 04/19/2017] [Indexed: 12/14/2022]
Abstract
Rhizobium leguminosarum has two high-affinity Mn2+ transport systems encoded by sitABCD and mntH. In symbiosis, sitABCD and mntH were expressed throughout nodules and also strongly induced in Mn2+ -limited cultures of free-living cells. Growth of a sitA mntH double mutant was severely reduced under Mn2+ limitation and sitA and mntH single mutants were more sensitive to oxidative stress. The double sitA mntH mutant of R. leguminosarum was unable to fix nitrogen (Fix- ) with legumes belonging to the galegoid clade (Pisum sativum, Vicia faba and Vicia hirsuta). The presence of infection thread-like structures and sparsely-packed plant cells in nodules suggest that bacteroid development was blocked, either at a late stage of infection thread progression or during bacteroid-release. In contrast, a double sitA mntH mutant was Fix+ on common bean (Phaseoli vulgaris), a member of the phaseoloid clade of legumes, indicating a host-specific symbiotic requirement for Mn2+ transport.
Collapse
Affiliation(s)
- Graham Hood
- Department of Molecular MicrobiologyJohn Innes CentreNorwich Research ParkNorwichNR4 7UHUK
| | - Vinoy Ramachandran
- Department of Plant SciencesUniversity of OxfordSouth Parks RoadOxfordOX1 3RBUK
| | - Alison K. East
- Department of Molecular MicrobiologyJohn Innes CentreNorwich Research ParkNorwichNR4 7UHUK
- Department of Plant SciencesUniversity of OxfordSouth Parks RoadOxfordOX1 3RBUK
| | - J. Allan Downie
- Department of Molecular MicrobiologyJohn Innes CentreNorwich Research ParkNorwichNR4 7UHUK
| | - Philip S. Poole
- Department of Molecular MicrobiologyJohn Innes CentreNorwich Research ParkNorwichNR4 7UHUK
- Department of Plant SciencesUniversity of OxfordSouth Parks RoadOxfordOX1 3RBUK
| |
Collapse
|
39
|
Pini F, East AK, Appia-Ayme C, Tomek J, Karunakaran R, Mendoza-Suárez M, Edwards A, Terpolilli JJ, Roworth J, Downie JA, Poole PS. Bacterial Biosensors for in Vivo Spatiotemporal Mapping of Root Secretion. PLANT PHYSIOLOGY 2017; 174:1289-1306. [PMID: 28495892 PMCID: PMC5490882 DOI: 10.1104/pp.16.01302] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Accepted: 05/06/2017] [Indexed: 05/20/2023]
Abstract
Plants engineer the rhizosphere to their advantage by secreting various nutrients and secondary metabolites. Coupling transcriptomic and metabolomic analyses of the pea (Pisum sativum) rhizosphere, a suite of bioreporters has been developed in Rhizobium leguminosarum bv viciae strain 3841, and these detect metabolites secreted by roots in space and time. Fourteen bacterial lux fusion bioreporters, specific for sugars, polyols, amino acids, organic acids, or flavonoids, have been validated in vitro and in vivo. Using different bacterial mutants (nodC and nifH), the process of colonization and symbiosis has been analyzed, revealing compounds important in the different steps of the rhizobium-legume association. Dicarboxylates and sucrose are the main carbon sources within the nodules; in ineffective (nifH) nodules, particularly low levels of sucrose were observed, suggesting that plant sanctions affect carbon supply to nodules. In contrast, high myo-inositol levels were observed prior to nodule formation and also in nifH senescent nodules. Amino acid biosensors showed different patterns: a γ-aminobutyrate biosensor was active only inside nodules, whereas the phenylalanine bioreporter showed a high signal also in the rhizosphere. The bioreporters were further validated in vetch (Vicia hirsuta), producing similar results. In addition, vetch exhibited a local increase of nod gene-inducing flavonoids at sites where nodules developed subsequently. These bioreporters will be particularly helpful in understanding the dynamics of root exudation and the role of different molecules secreted into the rhizosphere.
Collapse
Affiliation(s)
- Francesco Pini
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| | - Alison K East
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Corinne Appia-Ayme
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Jakub Tomek
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | | | - Marcela Mendoza-Suárez
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Anne Edwards
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Jason J Terpolilli
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Joshua Roworth
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| | - J Allan Downie
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Philip S Poole
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, United Kingdom
| |
Collapse
|
40
|
da-Silva JR, Alexandre A, Brígido C, Oliveira S. Can stress response genes be used to improve the symbiotic performance of rhizobia? AIMS Microbiol 2017; 3:365-382. [PMID: 31294167 PMCID: PMC6604987 DOI: 10.3934/microbiol.2017.3.365] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 05/16/2017] [Indexed: 12/31/2022] Open
Abstract
Rhizobia are soil bacteria able to form symbioses with legumes and fix atmospheric nitrogen, converting it into a form that can be assimilated by the plant. The biological nitrogen fixation is a possible strategy to reduce the environmental pollution caused by the use of chemical N-fertilizers in agricultural fields. Successful colonization of the host root by free-living rhizobia requires that these bacteria are able to deal with adverse conditions in the soil, in addition to stresses that may occur in their endosymbiotic life inside the root nodules. Stress response genes, such as otsAB, groEL, clpB, rpoH play an important role in tolerance of free-living rhizobia to different environmental conditions and some of these genes have been shown to be involved in the symbiosis. This review will focus on stress response genes that have been reported to improve the symbiotic performance of rhizobia with their host plants. For example, chickpea plants inoculated with a Mesorhizobium strain modified with extra copies of the groEL gene showed a symbiotic effectiveness approximately 1.5 fold higher than plants inoculated with the wild-type strain. Despite these promising results, more studies are required to obtain highly efficient and tolerant rhizobia strains, suitable for different edaphoclimatic conditions, to be used as field inoculants.
Collapse
Affiliation(s)
- José Rodrigo da-Silva
- Laboratório de Microbiologia do Solo, Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), Instituto de Investigação e Formação Avançada (IIFA), Universidade de Évora, Apartado 94, 7002-554 Évora, Portugal
| | - Ana Alexandre
- Laboratório de Microbiologia do Solo, Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), Instituto de Investigação e Formação Avançada (IIFA), Universidade de Évora, Apartado 94, 7002-554 Évora, Portugal
| | - Clarisse Brígido
- Laboratório de Microbiologia do Solo, Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), Instituto de Investigação e Formação Avançada (IIFA), Universidade de Évora, Apartado 94, 7002-554 Évora, Portugal
| | - Solange Oliveira
- Laboratório de Microbiologia do Solo, Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), Instituto de Investigação e Formação Avançada (IIFA), Universidade de Évora, Apartado 94, 7002-554 Évora, Portugal
| |
Collapse
|
41
|
Role of O2 in the Growth of Rhizobium leguminosarum bv. viciae 3841 on Glucose and Succinate. J Bacteriol 2016; 199:JB.00572-16. [PMID: 27795326 DOI: 10.1128/jb.00572-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 10/01/2016] [Indexed: 12/12/2022] Open
Abstract
Insertion sequencing (INSeq) analysis of Rhizobium leguminosarum bv. viciae 3841 (Rlv3841) grown on glucose or succinate at both 21% and 1% O2 was used to understand how O2 concentration alters metabolism. Two transcriptional regulators were required for growth on glucose (pRL120207 [eryD] and RL0547 [phoB]), five were required on succinate (pRL100388, RL1641, RL1642, RL3427, and RL4524 [ecfL]), and three were required on 1% O2 (pRL110072, RL0545 [phoU], and RL4042). A novel toxin-antitoxin system was identified that could be important for generation of new plasmidless rhizobial strains. Rlv3841 appears to use the methylglyoxal pathway alongside the Entner-Doudoroff (ED) pathway and tricarboxylic acid (TCA) cycle for optimal growth on glucose. Surprisingly, the ED pathway was required for growth on succinate, suggesting that sugars made by gluconeogenesis must undergo recycling. Altered amino acid metabolism was specifically needed for growth on glucose, including RL2082 (gatB) and pRL120419 (opaA, encoding omega-amino acid:pyruvate transaminase). Growth on succinate specifically required enzymes of nucleobase synthesis, including ribose-phosphate pyrophosphokinase (RL3468 [prs]) and a cytosine deaminase (pRL90208 [codA]). Succinate growth was particularly dependent on cell surface factors, including the PrsD-PrsE type I secretion system and UDP-galactose production. Only RL2393 (glnB, encoding nitrogen regulatory protein PII) was specifically essential for growth on succinate at 1% O2, conditions similar to those experienced by N2-fixing bacteroids. Glutamate synthesis is constitutively activated in glnB mutants, suggesting that consumption of 2-ketoglutarate may increase flux through the TCA cycle, leading to excess reductant that cannot be reoxidized at 1% O2 and cell death. IMPORTANCE Rhizobium leguminosarum, a soil bacterium that forms N2-fixing symbioses with several agriculturally important leguminous plants (including pea, vetch, and lentil), has been widely utilized as a model to study Rhizobium-legume symbioses. Insertion sequencing (INSeq) has been used to identify factors needed for its growth on different carbon sources and O2 levels. Identification of these factors is fundamental to a better understanding of the cell physiology and core metabolism of this bacterium, which adapts to a variety of different carbon sources and O2 tensions during growth in soil and N2 fixation in symbiosis with legumes.
Collapse
|
42
|
Terpolilli JJ, Masakapalli SK, Karunakaran R, Webb IUC, Green R, Watmough NJ, Kruger NJ, Ratcliffe RG, Poole PS. Lipogenesis and Redox Balance in Nitrogen-Fixing Pea Bacteroids. J Bacteriol 2016; 198:2864-75. [PMID: 27501983 PMCID: PMC5038014 DOI: 10.1128/jb.00451-16] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 07/26/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Within legume root nodules, rhizobia differentiate into bacteroids that oxidize host-derived dicarboxylic acids, which is assumed to occur via the tricarboxylic acid (TCA) cycle to generate NAD(P)H for reduction of N2 Metabolic flux analysis of laboratory-grown Rhizobium leguminosarum showed that the flux from [(13)C]succinate was consistent with respiration of an obligate aerobe growing on a TCA cycle intermediate as the sole carbon source. However, the instability of fragile pea bacteroids prevented their steady-state labeling under N2-fixing conditions. Therefore, comparative metabolomic profiling was used to compare free-living R. leguminosarum with pea bacteroids. While the TCA cycle was shown to be essential for maximal rates of N2 fixation, levels of pyruvate (5.5-fold reduced), acetyl coenzyme A (acetyl-CoA; 50-fold reduced), free coenzyme A (33-fold reduced), and citrate (4.5-fold reduced) were much lower in bacteroids. Instead of completely oxidizing acetyl-CoA, pea bacteroids channel it into both lipid and the lipid-like polymer poly-β-hydroxybutyrate (PHB), the latter via a type III PHB synthase that is active only in bacteroids. Lipogenesis may be a fundamental requirement of the redox poise of electron donation to N2 in all legume nodules. Direct reduction by NAD(P)H of the likely electron donors for nitrogenase, such as ferredoxin, is inconsistent with their redox potentials. Instead, bacteroids must balance the production of NAD(P)H from oxidation of acetyl-CoA in the TCA cycle with its storage in PHB and lipids. IMPORTANCE Biological nitrogen fixation by symbiotic bacteria (rhizobia) in legume root nodules is an energy-expensive process. Within legume root nodules, rhizobia differentiate into bacteroids that oxidize host-derived dicarboxylic acids, which is assumed to occur via the TCA cycle to generate NAD(P)H for reduction of N2 However, direct reduction of the likely electron donors for nitrogenase, such as ferredoxin, is inconsistent with their redox potentials. Instead, bacteroids must balance oxidation of plant-derived dicarboxylates in the TCA cycle with lipid synthesis. Pea bacteroids channel acetyl-CoA into both lipid and the lipid-like polymer poly-β-hydroxybutyrate, the latter via a type II PHB synthase. Lipogenesis is likely to be a fundamental requirement of the redox poise of electron donation to N2 in all legume nodules.
Collapse
Affiliation(s)
- Jason J Terpolilli
- Centre for Rhizobium Studies, Murdoch University, Perth, Australia Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | | | | | - Isabel U C Webb
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Rob Green
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | - Nicholas J Watmough
- Centre for Molecular Structure and Biochemistry, University of East Anglia, Norwich, United Kingdom
| | - Nicholas J Kruger
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - R George Ratcliffe
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Philip S Poole
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
43
|
Rachwał K, Boguszewska A, Kopcińska J, Karaś M, Tchórzewski M, Janczarek M. The Regulatory Protein RosR Affects Rhizobium leguminosarum bv. trifolii Protein Profiles, Cell Surface Properties, and Symbiosis with Clover. Front Microbiol 2016; 7:1302. [PMID: 27602024 PMCID: PMC4993760 DOI: 10.3389/fmicb.2016.01302] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 08/08/2016] [Indexed: 11/13/2022] Open
Abstract
Rhizobium leguminosarum bv. trifolii is capable of establishing a symbiotic relationship with plants from the genus Trifolium. Previously, a regulatory protein encoded by rosR was identified and characterized in this bacterium. RosR possesses a Cys2-His2-type zinc finger motif and belongs to Ros/MucR family of rhizobial transcriptional regulators. Transcriptome profiling of the rosR mutant revealed a role of this protein in several cellular processes, including the synthesis of cell-surface components and polysaccharides, motility, and bacterial metabolism. Here, we show that a mutation in rosR resulted in considerable changes in R. leguminosarum bv. trifolii protein profiles. Extracellular, membrane, and periplasmic protein profiles of R. leguminosarum bv. trifolii wild type and the rosR mutant were examined, and proteins with substantially different abundances between these strains were identified. Compared with the wild type, extracellular fraction of the rosR mutant contained greater amounts of several proteins, including Ca(2+)-binding cadherin-like proteins, a RTX-like protein, autoaggregation protein RapA1, and flagellins FlaA and FlaB. In contrast, several proteins involved in the uptake of various substrates were less abundant in the mutant strain (DppA, BraC, and SfuA). In addition, differences were observed in membrane proteins of the mutant and wild-type strains, which mainly concerned various transport system components. Using atomic force microscopy (AFM) imaging, we characterized the topography and surface properties of the rosR mutant and wild-type cells. We found that the mutation in rosR gene also affected surface properties of R. leguminosarum bv. trifolii. The mutant cells were significantly more hydrophobic than the wild-type cells, and their outer membrane was three times more permeable to the hydrophobic dye N-phenyl-1-naphthylamine. The mutation of rosR also caused defects in bacterial symbiotic interaction with clover plants. Compared with the wild type, the rosR mutant infected host plant roots much less effectively and its nodule occupation was disturbed. At the ultrastructural level, the most striking differences between the mutant and the wild-type nodules concerned the structure of infection threads, release of bacteria, and bacteroid differentiation. This confirms an essential role of RosR in establishment of successful symbiotic interaction of R. leguminosarum bv. trifolii with clover plants.
Collapse
Affiliation(s)
- Kamila Rachwał
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Maria Curie-Skłodowska University Lublin, Poland
| | - Aleksandra Boguszewska
- Department of Molecular Biology, Institute of Microbiology and Biotechnology, Maria Curie-Skłodowska University Lublin, Poland
| | - Joanna Kopcińska
- Department of Botany, Faculty of Agriculture and Biology, Warsaw University of Life Sciences Warsaw, Poland
| | - Magdalena Karaś
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Maria Curie-Skłodowska University Lublin, Poland
| | - Marek Tchórzewski
- Department of Molecular Biology, Institute of Microbiology and Biotechnology, Maria Curie-Skłodowska University Lublin, Poland
| | - Monika Janczarek
- Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Maria Curie-Skłodowska University Lublin, Poland
| |
Collapse
|
44
|
Vannini C, Carpentieri A, Salvioli A, Novero M, Marsoni M, Testa L, de Pinto MC, Amoresano A, Ortolani F, Bracale M, Bonfante P. An interdomain network: the endobacterium of a mycorrhizal fungus promotes antioxidative responses in both fungal and plant hosts. THE NEW PHYTOLOGIST 2016; 211:265-275. [PMID: 26914272 DOI: 10.1111/nph.13895] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 01/12/2016] [Indexed: 06/05/2023]
Abstract
Arbuscular mycorrhizal fungi (AMF) are obligate plant biotrophs that may contain endobacteria in their cytoplasm. Genome sequencing of Candidatus Glomeribacter gigasporarum revealed a reduced genome and dependence on the fungal host. RNA-seq analysis of the AMF Gigaspora margarita in the presence and absence of the endobacterium indicated that endobacteria have an important role in the fungal pre-symbiotic phase by enhancing fungal bioenergetic capacity. To improve the understanding of fungal-endobacterial interactions, iTRAQ (isobaric tags for relative and absolute quantification) quantitative proteomics was used to identify differentially expressed proteins in G. margarita germinating spores with endobacteria (B+), without endobacteria in the cured line (B-) and after application of the synthetic strigolactone GR24. Proteomic, transcriptomic and biochemical data identified several fungal and bacterial proteins involved in interspecies interactions. Endobacteria influenced fungal growth, calcium signalling and metabolism. The greatest effects were on fungal primary metabolism and respiration, which was 50% higher in B+ than in B-. A shift towards pentose phosphate metabolism was detected in B-. Quantification of carbonylated proteins indicated that the B- line had higher oxidative stress levels, which were also observed in two host plants. This study shows that endobacteria generate a complex interdomain network that affects AMF and fungal-plant interactions.
Collapse
Affiliation(s)
- Candida Vannini
- Department of Biotechnology and Life Science, Università dell'Insubria, via J.H. Dunant 3, I-21100, Varese, Italy
| | - Andrea Carpentieri
- Department of Chemical Sciences, Università di Napoli 'Federico II', via Cintia 4, I-80126, Napoli, Italy
| | - Alessandra Salvioli
- Department of Life Sciences and Systems Biology, Università di Torino, viale Mattioli 25, I-10125, Torino, Italy
| | - Mara Novero
- Department of Life Sciences and Systems Biology, Università di Torino, viale Mattioli 25, I-10125, Torino, Italy
| | - Milena Marsoni
- Department of Biotechnology and Life Science, Università dell'Insubria, via J.H. Dunant 3, I-21100, Varese, Italy
| | - Lorenzo Testa
- Department of Biotechnology and Life Science, Università dell'Insubria, via J.H. Dunant 3, I-21100, Varese, Italy
| | - Maria Concetta de Pinto
- Department of Biology, Università di Bari 'Aldo Moro', via E. Orabona 4, I-70125, Bari, Italy
| | - Angela Amoresano
- Department of Chemical Sciences, Università di Napoli 'Federico II', via Cintia 4, I-80126, Napoli, Italy
| | - Francesca Ortolani
- Department of Biotechnology and Life Science, Università dell'Insubria, via J.H. Dunant 3, I-21100, Varese, Italy
| | - Marcella Bracale
- Department of Biotechnology and Life Science, Università dell'Insubria, via J.H. Dunant 3, I-21100, Varese, Italy
| | - Paola Bonfante
- Department of Life Sciences and Systems Biology, Università di Torino, viale Mattioli 25, I-10125, Torino, Italy
| |
Collapse
|
45
|
Ramírez-Trujillo JA, Dunn MF, Suárez-Rodríguez R, Hernández-Lucas I. The Sinorhizobium meliloti glyoxylate cycle enzyme isocitrate lyase (AceA) is required for the utilization of poly-β-hydroxybutyrate during carbon starvation. ANN MICROBIOL 2016. [DOI: 10.1007/s13213-015-1131-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
|
46
|
Degli Esposti M, Martinez Romero E. A survey of the energy metabolism of nodulating symbionts reveals a new form of respiratory complex I. FEMS Microbiol Ecol 2016; 92:fiw084. [DOI: 10.1093/femsec/fiw084] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2016] [Indexed: 01/18/2023] Open
|
47
|
Scharf BE, Hynes MF, Alexandre GM. Chemotaxis signaling systems in model beneficial plant-bacteria associations. PLANT MOLECULAR BIOLOGY 2016; 90:549-59. [PMID: 26797793 DOI: 10.1007/s11103-016-0432-4] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 01/04/2016] [Indexed: 05/07/2023]
Abstract
Beneficial plant-microbe associations play critical roles in plant health. Bacterial chemotaxis provides a competitive advantage to motile flagellated bacteria in colonization of plant root surfaces, which is a prerequisite for the establishment of beneficial associations. Chemotaxis signaling enables motile soil bacteria to sense and respond to gradients of chemical compounds released by plant roots. This process allows bacteria to actively swim towards plant roots and is thus critical for competitive root surface colonization. The complete genome sequences of several plant-associated bacterial species indicate the presence of multiple chemotaxis systems and a large number of chemoreceptors. Further, most soil bacteria are motile and capable of chemotaxis, and chemotaxis-encoding genes are enriched in the bacteria found in the rhizosphere compared to the bulk soil. This review compares the architecture and diversity of chemotaxis signaling systems in model beneficial plant-associated bacteria and discusses their relevance to the rhizosphere lifestyle. While it is unclear how controlling chemotaxis via multiple parallel chemotaxis systems provides a competitive advantage to certain bacterial species, the presence of a larger number of chemoreceptors is likely to contribute to the ability of motile bacteria to survive in the soil and to compete for root surface colonization.
Collapse
Affiliation(s)
- Birgit E Scharf
- Department of Biological Sciences, Life Sciences I, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, USA
| | - Michael F Hynes
- Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Gladys M Alexandre
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA.
| |
Collapse
|
48
|
Paço A, Brígido C, Alexandre A, Mateos PF, Oliveira S. The Symbiotic Performance of Chickpea Rhizobia Can Be Improved by Additional Copies of the clpB Chaperone Gene. PLoS One 2016; 11:e0148221. [PMID: 26845770 PMCID: PMC4741418 DOI: 10.1371/journal.pone.0148221] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/14/2016] [Indexed: 12/03/2022] Open
Abstract
The ClpB chaperone is known to be involved in bacterial stress response. Moreover, recent studies suggest that this protein has also a role in the chickpea-rhizobia symbiosis. In order to improve both stress tolerance and symbiotic performance of a chickpea microsymbiont, the Mesorhizobium mediterraneum UPM-Ca36T strain was genetically transformed with pPHU231 containing an extra-copy of the clpB gene. To investigate if the clpB-transformed strain displays an improved stress tolerance, bacterial growth was evaluated under heat and acid stress conditions. In addition, the effect of the extra-copies of the clpB gene in the symbiotic performance was evaluated using plant growth assays (hydroponic and pot trials). The clpB-transformed strain is more tolerant to heat shock than the strain transformed with pPHU231, supporting the involvement of ClpB in rhizobia heat shock tolerance. Both plant growth assays showed that ClpB has an important role in chickpea-rhizobia symbiosis. The nodulation kinetics analysis showed a higher rate of nodule appearance with the clpB-transformed strain. This strain also induced a greater number of nodules and, more notably, its symbiotic effectiveness increased ~60% at pH5 and 83% at pH7, compared to the wild-type strain. Furthermore, a higher frequency of root hair curling was also observed in plants inoculated with the clpB-transformed strain, compared to the wild-type strain. The superior root hair curling induction, nodulation ability and symbiotic effectiveness of the clpB-transformed strain may be explained by an increased expression of symbiosis genes. Indeed, higher transcript levels of the nodulation genes nodA and nodC (~3 folds) were detected in the clpB-transformed strain. The improvement of rhizobia by addition of extra-copies of the clpB gene may be a promising strategy to obtain strains with enhanced stress tolerance and symbiotic effectiveness, thus contributing to their success as crop inoculants, particularly under environmental stresses. This is the first report on the successful improvement of a rhizobium with a chaperone gene.
Collapse
Affiliation(s)
- Ana Paço
- ICAAM–Instituto de Ciências Agrárias e Ambientais Mediterrânicas (Laboratório de Microbiologia do Solo), Universidade de Évora, Núcleo da Mitra, Ap. 94, 7002–554, Évora, Portugal
| | - Clarisse Brígido
- ICAAM–Instituto de Ciências Agrárias e Ambientais Mediterrânicas (Laboratório de Microbiologia do Solo), Universidade de Évora, Núcleo da Mitra, Ap. 94, 7002–554, Évora, Portugal
- IIFA–Instituto de Investigação e Formação Avançada, Universidade de Évora, Ap. 94, 7002–554, Évora, Portugal
| | - Ana Alexandre
- ICAAM–Instituto de Ciências Agrárias e Ambientais Mediterrânicas (Laboratório de Microbiologia do Solo), Universidade de Évora, Núcleo da Mitra, Ap. 94, 7002–554, Évora, Portugal
- IIFA–Instituto de Investigação e Formação Avançada, Universidade de Évora, Ap. 94, 7002–554, Évora, Portugal
| | - Pedro F. Mateos
- Departamento de Microbiología y Genética, Centro Hispano Luso de Investigaciones Agrarias, Universidad de Salamanca, 37007, Salamanca, Spain
| | - Solange Oliveira
- ICAAM–Instituto de Ciências Agrárias e Ambientais Mediterrânicas (Laboratório de Microbiologia do Solo), Universidade de Évora, Núcleo da Mitra, Ap. 94, 7002–554, Évora, Portugal
- * E-mail:
| |
Collapse
|
49
|
Cheng G, Karunakaran R, East AK, Poole PS. Multiplicity of Sulfate and Molybdate Transporters and Their Role in Nitrogen Fixation in Rhizobium leguminosarum bv. viciae Rlv3841. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2016; 29:143-52. [PMID: 26812045 DOI: 10.1094/mpmi-09-15-0215-r] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Rhizobium leguminosarum Rlv3841 contains at least three sulfate transporters, i.e., SulABCD, SulP1 and SulP2, and a single molybdate transporter, ModABC. SulABCD is a high-affinity transporter whose mutation prevented growth on a limiting sulfate concentration, while SulP1 and SulP2 appear to be low-affinity sulfate transporters. ModABC is the sole high-affinity molybdate transport system and is essential for growth with NO3(-) as a nitrogen source on limiting levels of molybdate (<0.25 μM). However, at 2.5 μM molybdate, a quadruple mutant with all four transporters inactivated, had the longest lag phase on NO3(-), suggesting these systems all make some contribution to molybdate transport. Growth of Rlv3841 on limiting levels of sulfate increased sulB, sulP1, modB, and sulP2 expression 313.3-, 114.7-, 6.2-, and 4.0-fold, respectively, while molybdate starvation increased only modB expression (three- to 7.5-fold). When grown in high-sulfate but not low-sulfate medium, pea plants inoculated with LMB695 (modB) reduced acetylene at only 14% of the wild-type rate, and this was not further reduced in the quadruple mutant. Overall, while modB is crucial to nitrogen fixation at limiting molybdate levels in the presence of sulfate, there is an unidentified molybdate transporter also capable of sulfate transport.
Collapse
Affiliation(s)
- Guojun Cheng
- 1 College of Life Science, South-Central University for Nationalities, Wuhan 430074, China
- 2 Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, U.K.; and
| | - Ramakrishnan Karunakaran
- 2 Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, U.K.; and
| | - Alison K East
- 2 Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, U.K.; and
- 3 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, U.K
| | - Philip S Poole
- 2 Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, U.K.; and
- 3 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, U.K
| |
Collapse
|
50
|
Hood G, Karunakaran R, Downie JA, Poole P. MgtE From Rhizobium leguminosarum Is a Mg²⁺ Channel Essential for Growth at Low pH and N2 Fixation on Specific Plants. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:1281-1287. [PMID: 26422403 DOI: 10.1094/mpmi-07-15-0166-r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
MgtE is predicted to be a Rhizobium leguminosarum channel and is essential for growth when both Mg²⁺ is limiting and the pH is low. N₂was only fixed at 8% of the rate of wild type when the crop legume Pisum sativum was inoculated with an mgtE mutant of R. leguminosarum and, although bacteroids were present, they were few in number and not fully developed. R. leguminosarum MgtE was also essential for N₂fixation on the native legume Vicia hirsuta but not when in symbiosis with Vicia faba. The importance of MgtE and the relevance of the contrasting phenotypes is discussed.
Collapse
Affiliation(s)
- Graham Hood
- 1 Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, U.K.; and
| | - Ramakrishnan Karunakaran
- 1 Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, U.K.; and
| | - J Allan Downie
- 1 Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, U.K.; and
| | - Philip Poole
- 1 Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, U.K.; and
- 2 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, U.K
| |
Collapse
|