1
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Limborg MT, Winther-Have CS, Morueta-Holme N, Gilbert MTP, Rasmussen JA. The overlooked biodiversity loss. Trends Ecol Evol 2024; 39:889-891. [PMID: 39209587 DOI: 10.1016/j.tree.2024.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 07/19/2024] [Accepted: 08/02/2024] [Indexed: 09/04/2024]
Abstract
As most life-forms exist as holobionts, reduction of host-level biodiversity drives parallel habitat losses to their host-adapted microorganisms. The holobiont concept helps us to understand how species are habitats for - often ignored - coevolved microorganisms also worthy of conservation. Indeed, loss of host-associated microbial biodiversity may accelerate the extinction risks of their host.
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Affiliation(s)
- Morten T Limborg
- Center for Evolutionary Hologenomics, Globe Institute, University of Copenhagen, Copenhagen, Denmark.
| | - Caroline S Winther-Have
- Center for Evolutionary Hologenomics, Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Naia Morueta-Holme
- Center for Macroecology, Evolution and Climate, Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - M Thomas P Gilbert
- Center for Evolutionary Hologenomics, Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Jacob A Rasmussen
- Center for Evolutionary Hologenomics, Globe Institute, University of Copenhagen, Copenhagen, Denmark
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2
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Kozaeva E, Eida AA, Gunady EF, Dangl JL, Conway JM, Brophy JA. Roots of synthetic ecology: microbes that foster plant resilience in the changing climate. Curr Opin Biotechnol 2024; 88:103172. [PMID: 39029405 DOI: 10.1016/j.copbio.2024.103172] [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: 03/18/2024] [Revised: 06/11/2024] [Accepted: 06/26/2024] [Indexed: 07/21/2024]
Abstract
Microbes orchestrate nearly all major biogeochemical processes. The ability to program their influence on plant growth and development is attractive for sustainable agriculture. However, the complexity of microbial ecosystems and our limited understanding of the mechanisms by which plants and microbes interact with each other and the environment make it challenging to use microbiomes to influence plant growth. Novel technologies at the intersection of microbial ecology, systems biology, and bioengineering provide new tools to probe the role of plant microbiomes across environments. Here, we summarize recent studies on plant and microbe responses to abiotic stresses, showcasing key molecules and micro-organisms that are important for plant health. We highlight opportunities to use synthetic microbial communities to understand the complexity of plant-microbial interactions and discuss future avenues of programming ecology to improve plant and ecosystem health.
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Affiliation(s)
- Ekaterina Kozaeva
- Department of Bioengineering, Stanford University, Stanford, CA, USA; Section of Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Abdul Aziz Eida
- Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ella F Gunady
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Jeffery L Dangl
- Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Jonathan M Conway
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA.
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3
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Griffin C, Oz MT, Demirer GS. Engineering plant-microbe communication for plant nutrient use efficiency. Curr Opin Biotechnol 2024; 88:103150. [PMID: 38810302 DOI: 10.1016/j.copbio.2024.103150] [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: 02/29/2024] [Revised: 05/13/2024] [Accepted: 05/13/2024] [Indexed: 05/31/2024]
Abstract
Nutrient availability and efficient use are critical for crop productivity. Current agricultural practices rely on excessive chemical fertilizers, contributing to greenhouse gas emissions and environmental pollution. Rhizosphere microbes facilitate plant nutrient acquisition and contribute to nutrient use efficiency. Thus, engineering plant-microbe communication within the rhizosphere emerges as a promising and sustainable strategy to enhance agricultural productivity. Recent advances in plant engineering have enabled the development of plants capable of selectively enriching beneficial microbes through root exudates. At the same time, synthetic biology techniques have produced microbes capable of improving nutrient availability and uptake by plants. By engineering plant-microbe communication, researchers aim to harness beneficial soil microbes, thereby offering a targeted and efficient approach to optimizing plant nutrient use efficiency.
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Affiliation(s)
- Catherine Griffin
- Department of Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - M Tufan Oz
- Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Gozde S Demirer
- Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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4
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Ledermann R, Bourdès A, Schuller M, Jorrin B, Ahel I, Poole PS. Aspartate aminotransferase of Rhizobium leguminosarum has extended substrate specificity and metabolizes aspartate to enable N 2 fixation in pea nodules. MICROBIOLOGY (READING, ENGLAND) 2024; 170. [PMID: 39073398 DOI: 10.1099/mic.0.001471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Rhizobium leguminosarum aspartate aminotransferase (AatA) mutants show drastically reduced symbiotic nitrogen fixation in legume nodules. Whilst AatA reversibly transaminates the two major amino-donor compounds aspartate and glutamate, the reason for the lack of N2 fixation in the mutant has remained unclear. During our investigations into the role of AatA, we found that it catalyses an additional transamination reaction between aspartate and pyruvate, forming alanine. This secondary reaction runs at around 60 % of the canonical aspartate transaminase reaction rate and connects alanine biosynthesis to glutamate via aspartate. This may explain the lack of any glutamate-pyruvate transaminase activity in R. leguminosarum, which is common in eukaryotic and many prokaryotic genomes. However, the aspartate-to-pyruvate transaminase reaction is not needed for N2 fixation in legume nodules. Consequently, we show that aspartate degradation is required for N2 fixation, rather than biosynthetic transamination to form an amino acid. Hence, the enzyme aspartase, which catalyses the breakdown of aspartate to fumarate and ammonia, suppressed an AatA mutant and restored N2 fixation in pea nodules.
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Affiliation(s)
| | - Alexandre Bourdès
- John Innes Centre, NR4 7UH, Norwich, UK
- School of Animal and Microbial Sciences, University of Reading, RG6 6AJ, Reading, UK
| | - Marion Schuller
- Sir William Dunn School of Pathology, University of Oxford, OX1 3RE, Oxford, UK
| | - Beatriz Jorrin
- Department of Biology, University of Oxford, OX1 3RB, Oxford, UK
| | - Ivan Ahel
- Sir William Dunn School of Pathology, University of Oxford, OX1 3RE, Oxford, UK
| | - Philip Simon Poole
- Department of Biology, University of Oxford, OX1 3RB, Oxford, UK
- John Innes Centre, NR4 7UH, Norwich, UK
- School of Animal and Microbial Sciences, University of Reading, RG6 6AJ, Reading, UK
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5
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Pfotenhauer AC, Lenaghan SC. Phytosensors: harnessing plants to understand the world around us. Curr Opin Biotechnol 2024; 87:103134. [PMID: 38705091 DOI: 10.1016/j.copbio.2024.103134] [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: 03/01/2024] [Revised: 04/04/2024] [Accepted: 04/09/2024] [Indexed: 05/07/2024]
Abstract
Although plants are sessile, their ubiquitous distribution, ability to harness energy from the sun, and ability to sense above and belowground signals make them ideal candidates for biosensor development. Synthetic biology has allowed scientists to reimagine biosensors as engineered devices that are focused on accomplishing novel tasks. As such, a new wave of plant-based sensors, phytosensors, are being engineered as multi-component sense-and-report devices that can alert human operators to a variety of hazards. While phytosensors are intrinsically tied to agriculture, a new generation of phytosensors has been envisioned to function in the built environment and even in austere environments, such as space. In this review, we will explore the current state of the art with regard to phytosensor engineering.
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Affiliation(s)
| | - Scott C Lenaghan
- Center for Agricultural Synthetic Biology, University of Tennessee, Knoxville, TN, USA; Department of Food Science, University of Tennessee, Knoxville, USA.
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6
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Chakraborty S, Venkataraman M, Infante V, Pfleger BF, Ané JM. Scripting a new dialogue between diazotrophs and crops. Trends Microbiol 2024; 32:577-589. [PMID: 37770375 PMCID: PMC10950843 DOI: 10.1016/j.tim.2023.08.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 08/14/2023] [Accepted: 08/15/2023] [Indexed: 09/30/2023]
Abstract
Diazotrophs are bacteria and archaea that can reduce atmospheric dinitrogen (N2) into ammonium. Plant-diazotroph interactions have been explored for over a century as a nitrogen (N) source for crops to improve agricultural productivity and sustainability. This scientific quest has generated much information about the molecular mechanisms underlying the function, assembly, and regulation of nitrogenase, ammonium assimilation, and plant-diazotroph interactions. This review presents various approaches to manipulating N fixation activity, ammonium release by diazotrophs, and plant-diazotroph interactions. We discuss the research avenues explored in this area, propose potential future routes, emphasizing engineering at the metabolic level via biorthogonal signaling, and conclude by highlighting the importance of biocontrol measures and public acceptance.
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Affiliation(s)
- Sanhita Chakraborty
- Department of Bacteriology, University of Wisconsin - Madison, Madison, WI, USA
| | - Maya Venkataraman
- Department of Chemical and Biological Engineering, University of Wisconsin - Madison, Madison, WI, USA
| | - Valentina Infante
- Department of Bacteriology, University of Wisconsin - Madison, Madison, WI, USA
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin - Madison, Madison, WI, USA
| | - Jean-Michel Ané
- Department of Bacteriology, University of Wisconsin - Madison, Madison, WI, USA; Department of Agronomy, University of Wisconsin - Madison, Madison, WI, USA.
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7
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Jorrin B, Haskett TL, Knights HE, Martyn A, Underwood TJ, Dolliver J, Ledermann R, Poole PS. Stable, fluorescent markers for tracking synthetic communities and assembly dynamics. MICROBIOME 2024; 12:81. [PMID: 38715147 PMCID: PMC11075435 DOI: 10.1186/s40168-024-01792-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 03/09/2024] [Indexed: 05/12/2024]
Abstract
BACKGROUND After two decades of extensive microbiome research, the current forefront of scientific exploration involves moving beyond description and classification to uncovering the intricate mechanisms underlying the coalescence of microbial communities. Deciphering microbiome assembly has been technically challenging due to their vast microbial diversity but establishing a synthetic community (SynCom) serves as a key strategy in unravelling this process. Achieving absolute quantification is crucial for establishing causality in assembly dynamics. However, existing approaches are primarily designed to differentiate a specific group of microorganisms within a particular SynCom. RESULTS To address this issue, we have developed the differential fluorescent marking (DFM) strategy, employing three distinguishable fluorescent proteins in single and double combinations. Building on the mini-Tn7 transposon, DFM capitalises on enhanced stability and broad applicability across diverse Proteobacteria species. The various DFM constructions are built using the pTn7-SCOUT plasmid family, enabling modular assembly, and facilitating the interchangeability of expression and antibiotic cassettes in a single reaction. DFM has no detrimental effects on fitness or community assembly dynamics, and through the application of flow cytometry, we successfully differentiated, quantified, and tracked a diverse six-member SynCom under various complex conditions like root rhizosphere showing a different colonisation assembly dynamic between pea and barley roots. CONCLUSIONS DFM represents a powerful resource that eliminates dependence on sequencing and/or culturing, thereby opening new avenues for studying microbiome assembly. Video Abstract.
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Affiliation(s)
- Beatriz Jorrin
- Molecular Plant Sciences Section, Department of Biology, University of Oxford, Oxford, OX1 3RB, UK.
| | - Timothy L Haskett
- Molecular Plant Sciences Section, Department of Biology, University of Oxford, Oxford, OX1 3RB, UK
| | - Hayley E Knights
- Molecular Plant Sciences Section, Department of Biology, University of Oxford, Oxford, OX1 3RB, UK
| | - Anna Martyn
- Molecular Plant Sciences Section, Department of Biology, University of Oxford, Oxford, OX1 3RB, UK
| | - Thomas J Underwood
- Molecular Plant Sciences Section, Department of Biology, University of Oxford, Oxford, OX1 3RB, UK
| | - Jessica Dolliver
- Molecular Plant Sciences Section, Department of Biology, University of Oxford, Oxford, OX1 3RB, UK
| | - Raphael Ledermann
- Molecular Plant Sciences Section, Department of Biology, University of Oxford, Oxford, OX1 3RB, UK
| | - Philip S Poole
- Molecular Plant Sciences Section, Department of Biology, University of Oxford, Oxford, OX1 3RB, UK
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8
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Boo A, Toth T, Yu Q, Pfotenhauer A, Fields BD, Lenaghan SC, Stewart CN, Voigt CA. Synthetic microbe-to-plant communication channels. Nat Commun 2024; 15:1817. [PMID: 38418817 PMCID: PMC10901793 DOI: 10.1038/s41467-024-45897-6] [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: 02/10/2023] [Accepted: 02/07/2024] [Indexed: 03/02/2024] Open
Abstract
Plants and microbes communicate to collaborate to stop pests, scavenge nutrients, and react to environmental change. Microbiota consisting of thousands of species interact with each other and plants using a large chemical language that is interpreted by complex regulatory networks. In this work, we develop modular interkingdom communication channels, enabling bacteria to convey environmental stimuli to plants. We introduce a "sender device" in Pseudomonas putida and Klebsiella pneumoniae, that produces the small molecule p-coumaroyl-homoserine lactone (pC-HSL) when the output of a sensor or circuit turns on. This molecule triggers a "receiver device" in the plant to activate gene expression. We validate this system in Arabidopsis thaliana and Solanum tuberosum (potato) grown hydroponically and in soil, demonstrating its modularity by swapping bacteria that process different stimuli, including IPTG, aTc and arsenic. Programmable communication channels between bacteria and plants will enable microbial sentinels to transmit information to crops and provide the building blocks for designing artificial consortia.
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Affiliation(s)
- Alice Boo
- Department of Biological Engineering, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Tyler Toth
- Department of Biological Engineering, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Qiguo Yu
- Department of Biological Engineering, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Alexander Pfotenhauer
- Center for Agricultural Synthetic Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Brandon D Fields
- Department of Biological Engineering, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Scott C Lenaghan
- Center for Agricultural Synthetic Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - C Neal Stewart
- Center for Agricultural Synthetic Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Christopher A Voigt
- Department of Biological Engineering, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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9
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Ragland CJ, Shih KY, Dinneny JR. Choreographing root architecture and rhizosphere interactions through synthetic biology. Nat Commun 2024; 15:1370. [PMID: 38355570 PMCID: PMC10866969 DOI: 10.1038/s41467-024-45272-5] [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: 07/17/2023] [Accepted: 01/18/2024] [Indexed: 02/16/2024] Open
Abstract
Climate change is driving extreme changes to the environment, posing substantial threats to global food security and bioenergy. Given the direct role of plant roots in mediating plant-environment interactions, engineering the form and function of root systems and their associated microbiota may mitigate these effects. Synthetic genetic circuits have enabled sophisticated control of gene expression in microbial systems for years and a surge of advances has heralded the extension of this approach to multicellular plant species. Targeting these tools to affect root structure, exudation, and microbe activity on root surfaces provide multiple strategies for the advancement of climate-ready crops.
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Affiliation(s)
- Carin J Ragland
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - Kevin Y Shih
- Department of Biology, Stanford University, Stanford, CA, 94305, USA
| | - José R Dinneny
- Department of Biology, Stanford University, Stanford, CA, 94305, USA.
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10
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Kashiwagi FM, Wendler Miranda B, Maltempi de Souza E, Müller-Santos M. The naringenin-dependent regulator FdeR can be applied as a NIMPLY gate controlled by naringenin and arabinose. Synth Biol (Oxf) 2024; 9:ysae001. [PMID: 38249314 PMCID: PMC10799723 DOI: 10.1093/synbio/ysae001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 12/07/2023] [Accepted: 01/05/2024] [Indexed: 01/23/2024] Open
Abstract
The FdeR regulator has been reported as a transcriptional activator dependent on the interaction with naringenin. Previously, FdeR and its cognate promoter were used to construct naringenin-sensitive sensors, though no correlation was associated between the FdeR level of expression and outputs. Therefore, to understand this correlation, we constructed a circuit with FdeR expression adjusted by the arabinose concentration through an AraC-PBAD system and the FdeR-regulated promoter controlling the expression of GFP. We observed a significant reduction in the activity of the target promoter by increasing FdeR expression, indicating that although FdeR has been primarily classified as a transcriptional activator, it also represses transcription. Leveraging the bifunctional feature of FdeR, acting as both transcriptional activator and repressor, we demonstrated that this genetic circuit, when previously switched on by naringenin, can be switched off by inducing an increased FdeR expression level. This engineered system functioned as a NIMPLY gate, effectively decreasing GFP expression by 50% when arabinose was added without removing naringenin from the medium. Exploiting FdeR versatility, this study demonstrates an innovative application of this transcriptional factor for developing novel NIMPLY gates activated by a molecule with low toxicity and nutraceutical properties that may be important for several applications. Graphical Abstract.
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Affiliation(s)
- Fernanda Miyuki Kashiwagi
- Postgraduate Program in Science (Biochemistry), Department of Biochemistry and Molecular Biology, Nitrogen Fixation Laboratory, Federal University of Paraná (UFPR), Curitiba, Brazil
| | - Brenno Wendler Miranda
- Postgraduate Program in Science (Biochemistry), Department of Biochemistry and Molecular Biology, Nitrogen Fixation Laboratory, Federal University of Paraná (UFPR), Curitiba, Brazil
| | - Emanuel Maltempi de Souza
- Postgraduate Program in Science (Biochemistry), Department of Biochemistry and Molecular Biology, Nitrogen Fixation Laboratory, Federal University of Paraná (UFPR), Curitiba, Brazil
| | - Marcelo Müller-Santos
- Postgraduate Program in Science (Biochemistry), Department of Biochemistry and Molecular Biology, Nitrogen Fixation Laboratory, Federal University of Paraná (UFPR), Curitiba, Brazil
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11
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Kim J, Lu LC, Gao X, Hofmockel KS, Masiello CA, Silberg JJ. Using Methyl Bromide for Interspecies Cell-Cell Signaling and As a Reporter in a Model Soil Consortium. ACS Synth Biol 2023; 12:3743-3753. [PMID: 37991716 DOI: 10.1021/acssynbio.3c00559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
Soil microbial communities with reduced complexity are emerging as model systems for studying consortia-scale phenotypes. To establish synthetic biology tools for studying these communities in hard-to-image environmental materials, we evaluated whether a single member of a model soil consortium (MSC) can be programmed to report on gene expression without requiring matrix disruption. For these studies, we targeted a five-membered MSC that includes Dyadobacter fermentans, Ensifer adhaerens, Rhodococcus sp003130705, Streptomyces sp001905665, and Variovorax beijingensis. By coupling the expression of a methyl halide transferase to a constitutive promoter, we show that V. beijingensis can be programmed to synthesize methyl halides that accumulate in the soil headspace at levels that are ≥24-fold higher than all other MSC members across a range of environmentally relevant hydration conditions. We find that methyl halide production can report on an MSC promoter that is activated by changes in water potential, and we demonstrate that a synthetic gas signal can be read out directly using gas chromatography and indirectly using a soil-derived Methylorubrum that is programmed to produce a visual output in response to methyl halides. These tools will be useful for future studies that investigate how MSC responds to dynamic hydration conditions, such as drought and flood events induced by climate change, which can alter soil water potential and induce the release of stored carbon.
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Affiliation(s)
- Jiwoo Kim
- Department of Biosciences, Rice University, 6100 Main Street, MS-140, Houston, Texas 77005, United States
| | - Li Chieh Lu
- Department of Biosciences, Rice University, 6100 Main Street, MS-140, Houston, Texas 77005, United States
| | - Xiaodong Gao
- Department of Earth, Environmental and Planetary Sciences, Rice University, 6100 Main St, MS-126, Houston, Texas 77005, United States
| | - Kirsten S Hofmockel
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Caroline A Masiello
- Department of Biosciences, Rice University, 6100 Main Street, MS-140, Houston, Texas 77005, United States
- Department of Earth, Environmental and Planetary Sciences, Rice University, 6100 Main St, MS-126, Houston, Texas 77005, United States
- Department of Chemistry, Rice University, 6100 Main Street, MS-60, Houston, Texas 77005, United States
| | - Jonathan J Silberg
- Department of Biosciences, Rice University, 6100 Main Street, MS-140, Houston, Texas 77005, United States
- Department of Bioengineering, Rice University, 6100 Main Street, MS-142, Houston, Texas 77005, United States
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, MS-362, Houston, Texas 77005, United States
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12
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Jansson JK, McClure R, Egbert RG. Soil microbiome engineering for sustainability in a changing environment. Nat Biotechnol 2023; 41:1716-1728. [PMID: 37903921 DOI: 10.1038/s41587-023-01932-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 08/01/2023] [Indexed: 11/01/2023]
Abstract
Recent advances in microbial ecology and synthetic biology have the potential to mitigate damage caused by anthropogenic activities that are deleteriously impacting Earth's soil ecosystems. Here, we discuss challenges and opportunities for harnessing natural and synthetic soil microbial communities, focusing on plant growth promotion under different scenarios. We explore current needs for microbial solutions in soil ecosystems, how these solutions are being developed and applied, and the potential for new biotechnology breakthroughs to tailor and target microbial products for specific applications. We highlight several scientific and technological advances in soil microbiome engineering, including characterization of microbes that impact soil ecosystems, directing how microbes assemble to interact in soil environments, and the developing suite of gene-engineering approaches. This Review underscores the need for an interdisciplinary approach to understand the composition, dynamics and deployment of beneficial soil microbiomes to drive efforts to mitigate or reverse environmental damage by restoring and protecting healthy soil ecosystems.
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Affiliation(s)
- Janet K Jansson
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA.
| | - Ryan McClure
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Robert G Egbert
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA
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13
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Ferguson S, Abel NB, Reid D, Madsen LH, Luu TB, Andersen KR, Stougaard J, Radutoiu S. A simple and efficient protocol for generating transgenic hairy roots using Agrobacterium rhizogenes. PLoS One 2023; 18:e0291680. [PMID: 37910566 PMCID: PMC10619795 DOI: 10.1371/journal.pone.0291680] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 09/01/2023] [Indexed: 11/03/2023] Open
Abstract
For decades, Agrobacterium rhizogenes (now Rhizobium rhizogenes), the causative agent of hairy root disease, has been harnessed as an interkingdom DNA delivery tool for generating transgenic hairy roots on a wide variety of plants. One of the strategies involves the construction of transconjugant R. rhizogenes by transferring gene(s) of interest into previously constructed R. rhizogenes pBR322 acceptor strains; little has been done, however, to improve upon this system since its implementation. We developed a simplified method utilising bi-parental mating in conjunction with effective counterselection for generating R. rhizogenes transconjugants. Central to this was the construction of a new Modular Cloning (MoClo) compatible pBR322-derived integration vector (pIV101). Although this protocol remains limited to pBR322 acceptor strains, pIV101 facilitated an efficient construction of recombinant vectors, effective screening of transconjugants, and RP4-based mobilisation compatibility that enabled simplified conjugal transfer. Transconjugants from this system were tested on Lotus japonicus and found to be efficient for the transformation of transgenic hairy roots and supported infection of nodules by a rhizobia symbiont. The expedited protocol detailed herein substantially decreased both the time and labour for creating transconjugant R. rhizogenes for the subsequent transgenic hairy root transformation of Lotus, and it could readily be applied for the transformation of other plants.
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Affiliation(s)
- Shaun Ferguson
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Nikolaj B. Abel
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Dugald Reid
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
- Department of Animal, Plant and Soil Sciences, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, Australia
| | - Lene H. Madsen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Thi-Bich Luu
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Kasper R. Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Jens Stougaard
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Simona Radutoiu
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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14
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Pan S, Zhang W, Li Y, Gao Y, Yu F, Tang Z, Zhu Y. Unveiling novel perspectives on niche differentiation and plasticity in rhizosphere phosphorus forms of submerged macrophytes with different stoichiometric homeostasis. WATER RESEARCH 2023; 246:120679. [PMID: 37806123 DOI: 10.1016/j.watres.2023.120679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/08/2023] [Accepted: 09/28/2023] [Indexed: 10/10/2023]
Abstract
Stoichiometric homeostasis is the ability of organisms to maintain their element composition through various physiological mechanisms, regardless of changes in nutrient availability. Phosphorus (P) is a critical limiting element for eutrophication. Submerged macrophytes with different stoichiometric homeostasis regulated sediment P pollution by nutrient resorption, but whether and how P homeostasis and resorption in submerged macrophytes changed under variable plant community structure was unclear. Increasing evidence suggests that rhizosphere microbes drive niche overlap and differentiation for different P forms to constitute submerged macrophyte community structure. However, a greater understanding of how this occurs is required. This study examined the process underlying the metabolism of different rhizosphere P forms of submerged macrophytes under different cultivation patterns by analyzing physicochemical data, basic plant traits, microbial communities, and transcriptomics. The results indicate that alkaline phosphatase serves as a key factor in revealing the existence of a link between plant traits (path coefficient = 0.335, p < 0.05) and interactions with rhizosphere microbial communities (average path coefficient = 0.362, p < 0.05). Moreover, this study demonstrates that microbial communities further influence the niche plasticity of P by mediating plant root P metabolism genes (path coefficient = 0.354, p < 0.05) and rhizosphere microbial phosphorus storage (average path coefficient = 0.605, p < 0.01). This research not only contributes to a deeper comprehension of stoichiometric homeostasis and nutrient dynamics but also provides valuable insights into potential strategies for managing and restoring submerged macrophyte-dominated ecosystems in the face of changing nutrient conditions.
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Affiliation(s)
- Shenyang Pan
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, PR China
| | - Wenlong Zhang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, PR China.
| | - Yi Li
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, PR China.
| | - Yu Gao
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, PR China
| | - Feng Yu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, PR China
| | - Zikang Tang
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, PR China
| | - Yajie Zhu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, PR China
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15
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Sugiyama A. Application of plant specialized metabolites to modulate soil microbiota. PLANT BIOTECHNOLOGY (TOKYO, JAPAN) 2023; 40:123-133. [PMID: 38250293 PMCID: PMC10797516 DOI: 10.5511/plantbiotechnology.23.0227a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Accepted: 02/27/2023] [Indexed: 01/23/2024]
Abstract
Plant specialized metabolites (PSMs) are considerably diverse compounds with multifaceted roles in the adaptation of plants to various abiotic and biotic stresses. PSMs are frequently secreted into the rhizosphere, a small region around the roots, where they facilitate interactions between plants and soil microorganisms. PSMs shape the host-specific rhizosphere microbial communities that potentially influence plant growth and tolerance to adverse conditions. Plant mutants defective in PSM biosynthesis contribute to reveal the roles of each PSM in plant-microbiota interactions in the rhizosphere. Recently, various approaches have been used to directly supply PSMs to soil by in vitro methods or through addition in pots with plants. This review focuses on the feasibility of the direct PSM application methods to reveal rhizospheric plant-microbiota interactions and discusses the possibility of applying the knowledge gained to future engineering of rhizospheric traits.
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Affiliation(s)
- Akifumi Sugiyama
- Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
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16
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Nadarajah K, Abdul Rahman NSN. The Microbial Connection to Sustainable Agriculture. PLANTS (BASEL, SWITZERLAND) 2023; 12:2307. [PMID: 37375932 DOI: 10.3390/plants12122307] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 06/01/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023]
Abstract
Microorganisms are an important element in modeling sustainable agriculture. Their role in soil fertility and health is crucial in maintaining plants' growth, development, and yield. Further, microorganisms impact agriculture negatively through disease and emerging diseases. Deciphering the extensive functionality and structural diversity within the plant-soil microbiome is necessary to effectively deploy these organisms in sustainable agriculture. Although both the plant and soil microbiome have been studied over the decades, the efficiency of translating the laboratory and greenhouse findings to the field is largely dependent on the ability of the inoculants or beneficial microorganisms to colonize the soil and maintain stability in the ecosystem. Further, the plant and its environment are two variables that influence the plant and soil microbiome's diversity and structure. Thus, in recent years, researchers have looked into microbiome engineering that would enable them to modify the microbial communities in order to increase the efficiency and effectiveness of the inoculants. The engineering of environments is believed to support resistance to biotic and abiotic stressors, plant fitness, and productivity. Population characterization is crucial in microbiome manipulation, as well as in the identification of potential biofertilizers and biocontrol agents. Next-generation sequencing approaches that identify both culturable and non-culturable microbes associated with the soil and plant microbiome have expanded our knowledge in this area. Additionally, genome editing and multidisciplinary omics methods have provided scientists with a framework to engineer dependable and sustainable microbial communities that support high yield, disease resistance, nutrient cycling, and management of stressors. In this review, we present an overview of the role of beneficial microbes in sustainable agriculture, microbiome engineering, translation of this technology to the field, and the main approaches used by laboratories worldwide to study the plant-soil microbiome. These initiatives are important to the advancement of green technologies in agriculture.
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Affiliation(s)
- Kalaivani Nadarajah
- Department of Biological Sciences and Biotechnology, Faculty of Sciences and Technology, University Kebangsaan Malaysia, Bangi 43600, Malaysia
| | - Nur Sabrina Natasha Abdul Rahman
- Department of Biological Sciences and Biotechnology, Faculty of Sciences and Technology, University Kebangsaan Malaysia, Bangi 43600, Malaysia
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17
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Liu Y, Wang H, Qian X, Gu J, Chen W, Shen X, Tao S, Jiao S, Wei G. Metagenomics insights into responses of rhizobacteria and their alleviation role in licorice allelopathy. MICROBIOME 2023; 11:109. [PMID: 37211607 PMCID: PMC10201799 DOI: 10.1186/s40168-023-01511-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 03/07/2023] [Indexed: 05/23/2023]
Abstract
BACKGROUND Allelopathy is closely associated with rhizosphere biological processes, and rhizosphere microbial communities are essential for plant development. However, our understanding of rhizobacterial communities under influence of allelochemicals in licorice remains limited. In the present study, the responses and effects of rhizobacterial communities on licorice allelopathy were investigated using a combination of multi-omics sequencing and pot experiments, under allelochemical addition and rhizobacterial inoculation treatments. RESULTS Here, we demonstrated that exogenous glycyrrhizin inhibits licorice development, and reshapes and enriches specific rhizobacteria and corresponding functions related to glycyrrhizin degradation. Moreover, the Novosphingobium genus accounted for a relatively high proportion of the enriched taxa and appeared in metagenomic assembly genomes. We further characterized the different capacities of single and synthetic inoculants to degrade glycyrrhizin and elucidated their distinct potency for alleviating licorice allelopathy. Notably, the single replenished N (Novosphingobium resinovorum) inoculant had the greatest allelopathy alleviation effects in licorice seedlings. CONCLUSIONS Altogether, the findings highlight that exogenous glycyrrhizin simulates the allelopathic autotoxicity effects of licorice, and indigenous single rhizobacteria had greater effects than synthetic inoculants in protecting licorice growth from allelopathy. The results of the present study enhance our understanding of rhizobacterial community dynamics during licorice allelopathy, with potential implications for resolving continuous cropping obstacle in medicinal plant agriculture using rhizobacterial biofertilizers. Video Abstract.
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Affiliation(s)
- Yang Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, 3 Taicheng Road, Yangling, Shaanxi, 712100, People's Republic of China
| | - Hao Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, 3 Taicheng Road, Yangling, Shaanxi, 712100, People's Republic of China
| | - Xun Qian
- Interdisciplinary Research Center for Soil Microbial Ecology and Land Sustainable Productivity in Dry Areas, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Jie Gu
- Interdisciplinary Research Center for Soil Microbial Ecology and Land Sustainable Productivity in Dry Areas, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
- College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Weimin Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, 3 Taicheng Road, Yangling, Shaanxi, 712100, People's Republic of China
| | - Xihui Shen
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, 3 Taicheng Road, Yangling, Shaanxi, 712100, People's Republic of China
| | - Shiheng Tao
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, 3 Taicheng Road, Yangling, Shaanxi, 712100, People's Republic of China
| | - Shuo Jiao
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, 3 Taicheng Road, Yangling, Shaanxi, 712100, People's Republic of China.
| | - Gehong Wei
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, 3 Taicheng Road, Yangling, Shaanxi, 712100, People's Republic of China.
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18
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Park I, Seo YS, Mannaa M. Recruitment of the rhizo-microbiome army: assembly determinants and engineering of the rhizosphere microbiome as a key to unlocking plant potential. Front Microbiol 2023; 14:1163832. [PMID: 37213524 PMCID: PMC10196466 DOI: 10.3389/fmicb.2023.1163832] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 04/11/2023] [Indexed: 05/23/2023] Open
Abstract
The viable community of microorganisms in the rhizosphere significantly impacts the physiological development and vitality of plants. The assembly and functional capacity of the rhizosphere microbiome are greatly influenced by various factors within the rhizosphere. The primary factors are the host plant genotype, developmental stage and status, soil properties, and resident microbiota. These factors drive the composition, dynamics, and activity of the rhizosphere microbiome. This review addresses the intricate interplay between these factors and how it facilitates the recruitment of specific microbes by the host plant to support plant growth and resilience under stress. This review also explores current methods for engineering and manipulating the rhizosphere microbiome, including host plant-mediated manipulation, soil-related methods, and microbe-mediated methods. Advanced techniques to harness the plant's ability to recruit useful microbes and the promising use of rhizo-microbiome transplantation are highlighted. The goal of this review is to provide valuable insights into the current knowledge, which will facilitate the development of cutting-edge strategies for manipulating the rhizosphere microbiome for enhanced plant growth and stress tolerance. The article also indicates promising avenues for future research in this field.
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Affiliation(s)
- Inmyoung Park
- School of Food and Culinary Arts, Youngsan University, Busan, Republic of Korea
| | - Young-Su Seo
- Department of Integrated Biological Science, Pusan National University, Busan, Republic of Korea
| | - Mohamed Mannaa
- Department of Integrated Biological Science, Pusan National University, Busan, Republic of Korea
- Department of Plant Pathology, Faculty of Agriculture, Cairo University, Giza, Egypt
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19
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Liu Q, Cheng L, Nian H, Jin J, Lian T. Linking plant functional genes to rhizosphere microbes: a review. PLANT BIOTECHNOLOGY JOURNAL 2023; 21:902-917. [PMID: 36271765 PMCID: PMC10106864 DOI: 10.1111/pbi.13950] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 10/09/2022] [Accepted: 10/16/2022] [Indexed: 05/04/2023]
Abstract
The importance of rhizomicrobiome in plant development, nutrition acquisition and stress tolerance is unquestionable. Relevant plant genes corresponding to the above functions also regulate rhizomicrobiome construction. Deciphering the molecular regulatory network of plant-microbe interactions could substantially contribute to improving crop yield and quality. Here, the plant gene-related nutrient uptake, biotic and abiotic stress resistance, which may influence the composition and function of microbial communities, are discussed in this review. In turn, the influence of microbes on the expression of functional plant genes, and thereby plant growth and immunity, is also reviewed. Moreover, we have specifically paid attention to techniques and methods used to link plant functional genes and rhizomicrobiome. Finally, we propose to further explore the molecular mechanisms and signalling pathways of microbe-host gene interactions, which could potentially be used for managing plant health in agricultural systems.
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Affiliation(s)
- Qi Liu
- The State Key Laboratory for Conservation and Utilization of Subtropical Agro‐BioresourcesSouth China Agricultural UniversityGuangzhouChina
- The Key Laboratory of Plant Molecular Breeding of Guangdong Province, College of AgricultureSouth China Agricultural UniversityGuangzhouChina
| | - Lang Cheng
- The State Key Laboratory for Conservation and Utilization of Subtropical Agro‐BioresourcesSouth China Agricultural UniversityGuangzhouChina
- The Key Laboratory of Plant Molecular Breeding of Guangdong Province, College of AgricultureSouth China Agricultural UniversityGuangzhouChina
| | - Hai Nian
- The State Key Laboratory for Conservation and Utilization of Subtropical Agro‐BioresourcesSouth China Agricultural UniversityGuangzhouChina
- The Key Laboratory of Plant Molecular Breeding of Guangdong Province, College of AgricultureSouth China Agricultural UniversityGuangzhouChina
| | - Jian Jin
- Northeast Institute of Geography and AgroecologyChinese Academy of SciencesHarbinChina
- Department of Animal, Plant and Soil Sciences, Centre for AgriBioscienceLa Trobe UniversityBundooraVictoriaAustralia
| | - Tengxiang Lian
- The State Key Laboratory for Conservation and Utilization of Subtropical Agro‐BioresourcesSouth China Agricultural UniversityGuangzhouChina
- The Key Laboratory of Plant Molecular Breeding of Guangdong Province, College of AgricultureSouth China Agricultural UniversityGuangzhouChina
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20
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Guo K, Yang J, Yu N, Luo L, Wang E. Biological nitrogen fixation in cereal crops: Progress, strategies, and perspectives. PLANT COMMUNICATIONS 2023; 4:100499. [PMID: 36447432 PMCID: PMC10030364 DOI: 10.1016/j.xplc.2022.100499] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/07/2022] [Accepted: 11/28/2022] [Indexed: 05/04/2023]
Abstract
Nitrogen is abundant in the atmosphere but is generally the most limiting nutrient for plants. The inability of many crop plants, such as cereals, to directly utilize freely available atmospheric nitrogen gas means that their growth and production often rely heavily on the application of chemical fertilizers, which leads to greenhouse gas emissions and the eutrophication of water. By contrast, legumes gain access to nitrogen through symbiotic association with rhizobia. These bacteria convert nitrogen gas into biologically available ammonia in nodules through a process termed symbiotic biological nitrogen fixation, which plays a decisive role in ecosystem functioning. Engineering cereal crops that can fix nitrogen like legumes or associate with nitrogen-fixing microbiomes could help to avoid the problems caused by the overuse of synthetic nitrogen fertilizer. With the development of synthetic biology, various efforts have been undertaken with the aim of creating so-called "N-self-fertilizing" crops capable of performing autonomous nitrogen fixation to avoid the need for chemical fertilizers. In this review, we briefly summarize the history and current status of engineering N-self-fertilizing crops. We also propose several potential biotechnological approaches for incorporating biological nitrogen fixation capacity into non-legume plants.
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Affiliation(s)
- Kaiyan Guo
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China; National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jun Yang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Nan Yu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China.
| | - Li Luo
- School of Life Sciences, Shanghai Key Laboratory of Bioenergy Crops, Shanghai University, Shanghai 200444, China.
| | - Ertao Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.
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21
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Jahn J, Diamond B, Hsu J, Montoya S, Totiger TM, Landgren O, Maura F, Taylor J. Therapy-selected clonal hematopoiesis and its role in myeloid neoplasms. Leuk Res 2023; 126:107020. [PMID: 36696829 PMCID: PMC11305114 DOI: 10.1016/j.leukres.2023.107020] [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: 11/22/2022] [Revised: 01/06/2023] [Accepted: 01/19/2023] [Indexed: 01/21/2023]
Abstract
Therapy-related myeloid neoplasms (t-MN) account for approximately 10-15% of all myeloid neoplasms and are associated with poor prognosis. Genomic characterization of t-MN to date has been limited in comparison to the considerable sequencing efforts performed for de novo myeloid neoplasms. Until recently, targeted deep sequencing (TDS) or whole exome sequencing (WES) have been the primary technologies utilized and thus limited the ability to explore the landscape of structural variants and mutational signatures. In the past decade, population-level studies have identified clonal hematopoiesis as a risk factor for the development of myeloid neoplasms. However, emerging research on clonal hematopoiesis as a risk factor for developing t-MN is evolving, and much is unknown about the progression of CH to t-MN. In this work, we will review the current knowledge of the genomic landscape of t-MN, discuss background knowledge of clonal hematopoiesis gained from studies of de novo myeloid neoplasms, and examine the recent literature studying the role of therapeutic selection of CH and its evolution under the effects of antineoplastic therapy. Finally, we will discuss the potential implications on current clinical practice and the areas of focus needed for future research into therapy-selected clonal hematopoiesis in myeloid neoplasms.
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Affiliation(s)
- Jacob Jahn
- Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine, United States
| | - Benjamin Diamond
- Myeloma Division, Department of Medicine, University of Miami Miller School of Medicine, United States
| | - Jeffrey Hsu
- Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine, United States
| | - Skye Montoya
- Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine, United States
| | - Tulasigeri M Totiger
- Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine, United States
| | - Ola Landgren
- Myeloma Division, Department of Medicine, University of Miami Miller School of Medicine, United States
| | - Francesco Maura
- Myeloma Division, Department of Medicine, University of Miami Miller School of Medicine, United States
| | - Justin Taylor
- Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine, United States; Leukemia Program, Department of Medicine, University of Miami Miller School of Medicine, United States.
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22
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Bennett EM, Murray JW, Isalan M. Engineering Nitrogenases for Synthetic Nitrogen Fixation: From Pathway Engineering to Directed Evolution. BIODESIGN RESEARCH 2023; 5:0005. [PMID: 37849466 PMCID: PMC10521693 DOI: 10.34133/bdr.0005] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 12/24/2022] [Indexed: 10/19/2023] Open
Abstract
Globally, agriculture depends on industrial nitrogen fertilizer to improve crop growth. Fertilizer production consumes fossil fuels and contributes to environmental nitrogen pollution. A potential solution would be to harness nitrogenases-enzymes capable of converting atmospheric nitrogen N2 to NH3 in ambient conditions. It is therefore a major goal of synthetic biology to engineer functional nitrogenases into crop plants, or bacteria that form symbiotic relationships with crops, to support growth and reduce dependence on industrially produced fertilizer. This review paper highlights recent work toward understanding the functional requirements for nitrogenase expression and manipulating nitrogenase gene expression in heterologous hosts to improve activity and oxygen tolerance and potentially to engineer synthetic symbiotic relationships with plants.
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Affiliation(s)
- Emily M. Bennett
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - James W. Murray
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | - Mark Isalan
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
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23
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Haskett TL, Geddes BA, Paramasivan P, Green P, Chitnavis S, Mendes MD, Jorrín B, Knights HE, Bastholm TR, Ramsay JP, Oldroyd GED, Poole PS. Rhizopine biosensors for plant-dependent control of bacterial gene expression. Environ Microbiol 2023; 25:383-396. [PMID: 36428208 PMCID: PMC10107442 DOI: 10.1111/1462-2920.16288] [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: 09/28/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022]
Abstract
Engineering signalling between plants and microbes could be exploited to establish host-specificity between plant-growth-promoting bacteria and target crops in the environment. We previously engineered rhizopine-signalling circuitry facilitating exclusive signalling between rhizopine-producing (RhiP) plants and model bacterial strains. Here, we conduct an in-depth analysis of rhizopine-inducible expression in bacteria. We characterize two rhizopine-inducible promoters and explore the bacterial host-range of rhizopine biosensor plasmids. By tuning the expression of rhizopine uptake genes, we also construct a new biosensor plasmid pSIR05 that has minimal impact on host cell growth in vitro and exhibits markedly improved stability of expression in situ on RhiP barley roots compared to the previously described biosensor plasmid pSIR02. We demonstrate that a sub-population of Azorhizobium caulinodans cells carrying pSIR05 can sense rhizopine and activate gene expression when colonizing RhiP barley roots. However, these bacteria were mildly defective for colonization of RhiP barley roots compared to the wild-type parent strain. This work provides advancement towards establishing more robust plant-dependent control of bacterial gene expression and highlights the key challenges remaining to achieve this goal.
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Affiliation(s)
| | - Barney A Geddes
- Department of Plant Sciences, University of Oxford, Oxford, UK
- Department of Microbiological Sciences, North Dakota State University, Fargo, North Dakota, USA
| | | | - Patrick Green
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Samir Chitnavis
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Marta D Mendes
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Beatriz Jorrín
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | | | - Tahlia R Bastholm
- Curtin Medical School and Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia
| | - Joshua P Ramsay
- Curtin Medical School and Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia, Australia
| | - Giles E D Oldroyd
- Sainsbury Laboratory, University of Cambridge, Cambridge, UK
- Crop Science Centre, University of Cambridge, Cambridge, UK
| | - Philip S Poole
- Department of Plant Sciences, University of Oxford, Oxford, UK
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24
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Molecular Mechanism and Agricultural Application of the NifA-NifL System for Nitrogen Fixation. Int J Mol Sci 2023; 24:ijms24020907. [PMID: 36674420 PMCID: PMC9866876 DOI: 10.3390/ijms24020907] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/27/2022] [Accepted: 12/30/2022] [Indexed: 01/06/2023] Open
Abstract
Nitrogen-fixing bacteria execute biological nitrogen fixation through nitrogenase, converting inert dinitrogen (N2) in the atmosphere into bioavailable nitrogen. Elaborating the molecular mechanisms of orderly and efficient biological nitrogen fixation and applying them to agricultural production can alleviate the "nitrogen problem". Azotobacter vinelandii is a well-established model bacterium for studying nitrogen fixation, utilizing nitrogenase encoded by the nif gene cluster to fix nitrogen. In Azotobacter vinelandii, the NifA-NifL system fine-tunes the nif gene cluster transcription by sensing the redox signals and energy status, then modulating nitrogen fixation. In this manuscript, we investigate the transcriptional regulation mechanism of the nif gene in autogenous nitrogen-fixing bacteria. We discuss how autogenous nitrogen fixation can better be integrated into agriculture, providing preliminary comprehensive data for the study of autogenous nitrogen-fixing regulation.
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25
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Eckardt NA, Ainsworth EA, Bahuguna RN, Broadley MR, Busch W, Carpita NC, Castrillo G, Chory J, DeHaan LR, Duarte CM, Henry A, Jagadish SVK, Langdale JA, Leakey ADB, Liao JC, Lu KJ, McCann MC, McKay JK, Odeny DA, Jorge de Oliveira E, Platten JD, Rabbi I, Rim EY, Ronald PC, Salt DE, Shigenaga AM, Wang E, Wolfe M, Zhang X. Climate change challenges, plant science solutions. THE PLANT CELL 2023; 35:24-66. [PMID: 36222573 PMCID: PMC9806663 DOI: 10.1093/plcell/koac303] [Citation(s) in RCA: 42] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
Climate change is a defining challenge of the 21st century, and this decade is a critical time for action to mitigate the worst effects on human populations and ecosystems. Plant science can play an important role in developing crops with enhanced resilience to harsh conditions (e.g. heat, drought, salt stress, flooding, disease outbreaks) and engineering efficient carbon-capturing and carbon-sequestering plants. Here, we present examples of research being conducted in these areas and discuss challenges and open questions as a call to action for the plant science community.
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Affiliation(s)
- Nancy A Eckardt
- Senior Features Editor, The Plant Cell, American Society of Plant Biologists, USA
| | - Elizabeth A Ainsworth
- USDA ARS Global Change and Photosynthesis Research Unit, Urbana, Illinois 61801, USA
| | - Rajeev N Bahuguna
- Centre for Advanced Studies on Climate Change, Dr Rajendra Prasad Central Agricultural University, Samastipur 848125, Bihar, India
| | - Martin R Broadley
- School of Biosciences, University of Nottingham, Nottingham, NG7 2RD, UK
- Rothamsted Research, West Common, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Wolfgang Busch
- Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Nicholas C Carpita
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, USA
| | - Gabriel Castrillo
- School of Biosciences, University of Nottingham, Nottingham, NG7 2RD, UK
- Future Food Beacon of Excellence, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Joanne Chory
- Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA
- Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | | | - Carlos M Duarte
- Red Sea Research Center (RSRC) and Computational Bioscience Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Amelia Henry
- International Rice Research Institute, Rice Breeding Innovations Platform, Los Baños, Laguna 4031, Philippines
| | - S V Krishna Jagadish
- Department of Plant and Soil Science, Texas Tech University, Lubbock, Texas 79410, USA
| | - Jane A Langdale
- Department of Biology, University of Oxford, Oxford, OX1 3RB, UK
| | - Andrew D B Leakey
- Department of Plant Biology, Department of Crop Sciences, and Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Illinois 61801, USA
| | - James C Liao
- Institute of Biological Chemistry, Academia Sinica, Taipei 11528, Taiwan
| | - Kuan-Jen Lu
- Institute of Biological Chemistry, Academia Sinica, Taipei 11528, Taiwan
| | - Maureen C McCann
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, USA
| | - John K McKay
- Department of Agricultural Biology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Damaris A Odeny
- The International Crops Research Institute for the Semi-Arid Tropics–Eastern and Southern Africa, Gigiri 39063-00623, Nairobi, Kenya
| | | | - J Damien Platten
- International Rice Research Institute, Rice Breeding Innovations Platform, Los Baños, Laguna 4031, Philippines
| | - Ismail Rabbi
- International Institute of Tropical Agriculture (IITA), PMB 5320 Ibadan, Oyo, Nigeria
| | - Ellen Youngsoo Rim
- Department of Plant Pathology and the Genome Center, University of California, Davis, California 95616, USA
| | - Pamela C Ronald
- Department of Plant Pathology and the Genome Center, University of California, Davis, California 95616, USA
- Innovative Genomics Institute, Berkeley, California 94704, USA
| | - David E Salt
- School of Biosciences, University of Nottingham, Nottingham, NG7 2RD, UK
- Future Food Beacon of Excellence, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Alexandra M Shigenaga
- Department of Plant Pathology and the Genome Center, University of California, Davis, California 95616, USA
| | - Ertao Wang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Marnin Wolfe
- Auburn University, Dept. of Crop Soil and Environmental Sciences, College of Agriculture, Auburn, Alabama 36849, USA
| | - Xiaowei Zhang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
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26
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Sutherland WJ, Bennett C, Brotherton PNM, Butterworth HM, Clout MN, Côté IM, Dinsdale J, Esmail N, Fleishman E, Gaston KJ, Herbert-Read JE, Hughes A, Kaartokallio H, Le Roux X, Lickorish FA, Matcham W, Noor N, Palardy JE, Pearce-Higgins JW, Peck LS, Pettorelli N, Pretty J, Scobey R, Spalding MD, Tonneijck FH, Tubbs N, Watson JEM, Wentworth JE, Wilson JD, Thornton A. A global biological conservation horizon scan of issues for 2023. Trends Ecol Evol 2023; 38:96-107. [PMID: 36460563 DOI: 10.1016/j.tree.2022.10.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 10/24/2022] [Accepted: 10/25/2022] [Indexed: 12/03/2022]
Abstract
We present the results of our 14th horizon scan of issues we expect to influence biological conservation in the future. From an initial set of 102 topics, our global panel of 30 scientists and practitioners identified 15 issues we consider most urgent for societies worldwide to address. Issues are novel within biological conservation or represent a substantial positive or negative step change at global or regional scales. Issues such as submerged artificial light fisheries and accelerating upper ocean currents could have profound negative impacts on marine or coastal ecosystems. We also identified potentially positive technological advances, including energy production and storage, improved fertilisation methods, and expansion of biodegradable materials. If effectively managed, these technologies could realise future benefits for biological diversity.
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Affiliation(s)
- William J Sutherland
- Conservation Science Group, Department of Zoology, Cambridge University, The David Attenborough Building, Pembroke Street, Cambridge CB2 3QZ, UK; Biosecurity Research Initiative at St Catharine's (BioRISC), St Catharine's College, University of Cambridge, Cambridge, UK.
| | - Craig Bennett
- Royal Society of Wildlife Trusts, The Kiln, Waterside, Mather Road, Newark, Nottinghamshire NG24 1WT, UK
| | - Peter N M Brotherton
- Natural England, 4th Floor Foss House, Kings Pool, 1-2 Peasholme Green, York YO1 7PX, UK
| | - Holly M Butterworth
- Natural Resources Wales, Cambria House, 29 Newport Road, Cardiff CF24 0TP, UK
| | - Mick N Clout
- Centre for Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland, PB 92019, Auckland, New Zealand
| | - Isabelle M Côté
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Jason Dinsdale
- Environment Agency, Horizon House, Deanery Road, Bristol BS1 5AH, UK
| | - Nafeesa Esmail
- Wilder Institute/Calgary Zoo, 1300 Zoo Road NE, Calgary, AB T2E 7V6, Canada
| | - Erica Fleishman
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Kevin J Gaston
- Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9FE, UK
| | | | - Alice Hughes
- School of Biological Sciences, University of Hong Kong, Pok Fu Lam, Hong Kong
| | | | - Xavier Le Roux
- University of Lyon, Microbial Ecology Centre, INRAE (UMR1418), CNRS (UMR5557), University Lyon 1, 69622 Villeurbanne, France
| | - Fiona A Lickorish
- UK Research and Consultancy Services (RCS) Ltd, Valletts Cottage, Westhope, Hereford HR4 8BU, UK
| | - Wendy Matcham
- Natural Environment Research Council, UK Research and Innovation, Polaris House, North Star Avenue, Swindon SN2 1FL, UK
| | - Noor Noor
- UN Environment Programme World Conservation Monitoring Centre (UNEP-WCMC), 219 Huntingdon Road, Cambridge CB3 0DL, UK
| | - James E Palardy
- The Pew Charitable Trusts, 901 E St. NW, Washington, DC 20004, USA
| | - James W Pearce-Higgins
- Conservation Science Group, Department of Zoology, Cambridge University, The David Attenborough Building, Pembroke Street, Cambridge CB2 3QZ, UK; British Trust for Ornithology, The Nunnery, Thetford, Norfolk IP24 2PU, UK
| | - Lloyd S Peck
- British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Nathalie Pettorelli
- Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK
| | - Jules Pretty
- Centre for Public and Policy Engagement and School of Life Sciences, University of Essex, Colchester CO4 3SQ, UK
| | - Richard Scobey
- TRAFFIC, The David Attenborough Building, Pembroke Street, Cambridge CB2 3QZ, UK
| | - Mark D Spalding
- Conservation Science Group, Department of Zoology, Cambridge University, The David Attenborough Building, Pembroke Street, Cambridge CB2 3QZ, UK; The Nature Conservancy, Strade delle Tolfe, 14, Siena 53100, Italy
| | | | - Nicolas Tubbs
- WWF-Belgium, BD Emile Jacqumainlaan 90, 1000 Brussels, Belgium
| | - James E M Watson
- School of Earth and Environmental Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Jonathan E Wentworth
- Parliamentary Office of Science and Technology, 14 Tothill Street, Westminster, London SW1H 9NB, UK
| | - Jeremy D Wilson
- RSPB Centre for Conservation Science, 2 Lochside View, Edinburgh EH12 9DH, UK
| | - Ann Thornton
- Conservation Science Group, Department of Zoology, Cambridge University, The David Attenborough Building, Pembroke Street, Cambridge CB2 3QZ, UK
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Alexander A, Singh VK, Mishra A. Introgression of a novel gene AhBINR differentially expressed during PGPR Brachybacterium saurashtrense-Arachis hypogaea interaction enhances plant performance under nitrogen starvation and salt stress in tobacco. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 324:111429. [PMID: 36029896 DOI: 10.1016/j.plantsci.2022.111429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 08/08/2022] [Accepted: 08/19/2022] [Indexed: 06/15/2023]
Abstract
Plant growth-promoting rhizobacteria provide endurance during environmental stress conditions. Previously, we have shown that the interaction of the halotolerant diazotrophic bacteria Brachybacterium saurashtrense JG06 induces physio-biochemical and molecular changes in Arachis hypogaea under nitrogen starvation conditions. Here we deciphered the role of a novel gene AhBINR that was differentially overexpressed in A. hypogaea after interaction with B. saurashtrense JG06 under nitrogen deficit conditions. Overexpression of the AhBINR gene in the model plant (tobacco) showed higher growth parameters (root length, shoot length, fresh weight, and dry weight) under nitrogen starvation and salt stress in comparison to the wild type and vector control. Transgenic plants were enabled with a higher photosynthesis rate, which provides the support for better performance under N2 starvation and salt stress. Results showed that the transgenic plants overexpressing the AhBINR gene had better physiological status and lower ROS accumulation under adverse conditions. Microarray transcriptome analysis showed that the transcription factors, biotic and abiotic stress, photosynthesis, and metabolism-related genes were differentially expressed (total 736 and 6530 genes were expressed under nitrogen deficit and salt stress conditions, respectively at a 5-fold change level) in comparison to wild type plants. Overall results showed the involvement of the AhBINR gene in the activation of the abiotic stress (nitrogen starvation and salt stress) related pathways, which can be overexpressed after legume-rhizobacterial interaction.
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Affiliation(s)
- Ankita Alexander
- Division of Applied Phycology and Biotechnology, CSIR, Central Salt and Marine Chemicals Research Institute, G. B. Marg, Bhavnagar 364002, Gujarat, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
| | - Vijay K Singh
- Division of Applied Phycology and Biotechnology, CSIR, Central Salt and Marine Chemicals Research Institute, G. B. Marg, Bhavnagar 364002, Gujarat, India.
| | - Avinash Mishra
- Division of Applied Phycology and Biotechnology, CSIR, Central Salt and Marine Chemicals Research Institute, G. B. Marg, Bhavnagar 364002, Gujarat, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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28
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Klein M, Stewart JD, Porter SS, Weedon JT, Kiers ET. Evolution of manipulative microbial behaviors in the rhizosphere. Evol Appl 2022; 15:1521-1536. [PMID: 36330300 PMCID: PMC9624083 DOI: 10.1111/eva.13333] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/30/2021] [Accepted: 12/02/2021] [Indexed: 01/01/2023] Open
Abstract
The rhizosphere has been called "one of the most complex ecosystems on earth" because it is a hotspot for interactions among millions of microbial cells. Many of these are microbes are also participating in a dynamic interplay with host plant tissues, signaling pathways, and metabolites. Historically, breeders have employed a plant-centric perspective when trying to harness the potential of microbiome-derived benefits to improve productivity and resilience of economically important plants. This is potentially problematic because: (i) the evolution of the microbes themselves is often ignored, and (ii) it assumes that the fitness of interacting plants and microbes is strictly aligned. In contrast, a microbe-centric perspective recognizes that putatively beneficial microbes are still under selection to increase their own fitness, even if there are costs to the host. This can lead to the evolution of sophisticated, potentially subtle, ways for microbes to manipulate the phenotype of their hosts, as well as other microbes in the rhizosphere. We illustrate this idea with a review of cases where rhizosphere microbes have been demonstrated to directly manipulate host root growth, architecture and exudation, host nutrient uptake systems, and host immunity and defense. We also discuss indirect effects, whereby fitness outcomes for the plant are a consequence of ecological interactions between rhizosphere microbes. If these consequences are positive for the plant, they can potentially be misconstrued as traits that have evolved to promote host growth, even if they are a result of selection for unrelated functions. The ubiquity of both direct microbial manipulation of hosts and context-dependent, variable indirect effects leads us to argue that an evolutionary perspective on rhizosphere microbial ecology will become increasingly important as we continue to engineer microbial communities for crop production.
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Affiliation(s)
- Malin Klein
- Department of Ecological ScienceVrije Universiteit AmsterdamAmsterdamThe Netherlands
| | - Justin D. Stewart
- Department of Ecological ScienceVrije Universiteit AmsterdamAmsterdamThe Netherlands
| | - Stephanie S. Porter
- School of Biological SciencesWashington State UniversityVancouverWashingtonUSA
| | - James T. Weedon
- Department of Ecological ScienceVrije Universiteit AmsterdamAmsterdamThe Netherlands
| | - E. Toby Kiers
- Department of Ecological ScienceVrije Universiteit AmsterdamAmsterdamThe Netherlands
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29
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Gomide MDS, Leitão MDC, Coelho CM. Biocircuits in plants and eukaryotic algae. FRONTIERS IN PLANT SCIENCE 2022; 13:982959. [PMID: 36212277 PMCID: PMC9545776 DOI: 10.3389/fpls.2022.982959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/22/2022] [Indexed: 06/16/2023]
Abstract
As one of synthetic biology's foundations, biocircuits are a strategy of genetic parts assembling to recognize a signal and to produce a desirable output to interfere with a biological function. In this review, we revisited the progress in the biocircuits technology basis and its mandatory elements, such as the characterization and assembly of functional parts. Furthermore, for a successful implementation, the transcriptional control systems are a relevant point, and the computational tools help to predict the best combinations among the biological parts planned to be used to achieve the desirable phenotype. However, many challenges are involved in delivering and stabilizing the synthetic structures. Some research experiences, such as the golden crops, biosensors, and artificial photosynthetic structures, can indicate the positive and limiting aspects of the practice. Finally, we envision that the modulatory structural feature and the possibility of finer gene regulation through biocircuits can contribute to the complex design of synthetic chromosomes aiming to develop plants and algae with new or improved functions.
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Affiliation(s)
- Mayna da Silveira Gomide
- Laboratory of Synthetic Biology, Department of Genetics and Morphology, Institute of Biological Science, University of Brasília (UnB), Brasília, Distrito Federal, Brazil
- School of Medicine, Federal University of Juiz de Fora (UFJF), Juiz de Fora, Minas Gerais, Brazil
| | - Matheus de Castro Leitão
- Laboratory of Synthetic Biology, Department of Genetics and Morphology, Institute of Biological Science, University of Brasília (UnB), Brasília, Distrito Federal, Brazil
| | - Cíntia Marques Coelho
- Laboratory of Synthetic Biology, Department of Genetics and Morphology, Institute of Biological Science, University of Brasília (UnB), Brasília, Distrito Federal, Brazil
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30
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Birt HWG, Tharp CL, Custer GF, Dini-Andreote F. Root phenotypes as modulators of microbial microhabitats. FRONTIERS IN PLANT SCIENCE 2022; 13:1003868. [PMID: 36212354 PMCID: PMC9539067 DOI: 10.3389/fpls.2022.1003868] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 09/08/2022] [Indexed: 06/09/2023]
Abstract
Plant roots are colonized by a multitude of microbial taxa that dynamically influence plant health. Plant-microbe interactions at the root-soil interface occur at the micro-scale and are affected by variation in root phenotypes. Different root phenotypes can have distinct impacts on physical and chemical gradients at the root-soil interface, leading to heterogeneous microhabitats for microbial colonization. Microbes that influence plant physiology will establish across these heterogeneous microhabitats, and, therefore, exploiting variation in root phenotypes can allow for targeted manipulation of plant-associated microbes. In this mini-review, we discuss how changes in root anatomy and architecture can influence resource availability and the spatial configuration of microbial microhabitats. We then propose research priorities that integrate root phenotypes and microbial microhabitats for advancing the manipulation of root-associated microbiomes. We foresee the yet-unexplored potential to harness diverse root phenotypes as a new level of precision in microbiome management in plant-root systems.
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31
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Mars Brisbin M, Mitarai S, Saito MA, Alexander H. Microbiomes of bloom-forming Phaeocystis algae are stable and consistently recruited, with both symbiotic and opportunistic modes. THE ISME JOURNAL 2022; 16:2255-2264. [PMID: 35764675 PMCID: PMC9381791 DOI: 10.1038/s41396-022-01263-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 05/11/2022] [Accepted: 05/31/2022] [Indexed: 05/29/2023]
Abstract
Phaeocystis is a cosmopolitan, bloom-forming phytoplankton genus that contributes significantly to global carbon and sulfur cycles. During blooms, Phaeocystis species produce large carbon-rich colonies, creating a unique interface for bacterial interactions. While bacteria are known to interact with phytoplankton-e.g., they promote growth by producing phytohormones and vitamins-such interactions have not been shown for Phaeocystis. Therefore, we investigated the composition and function of P. globosa microbiomes. Specifically, we tested whether microbiome compositions are consistent across individual colonies from four P. globosa strains, whether similar microbiomes are re-recruited after antibiotic treatment, and how microbiomes affect P. globosa growth under limiting conditions. Results illuminated a core colonial P. globosa microbiome-including bacteria from the orders Alteromonadales, Burkholderiales, and Rhizobiales-that was re-recruited after microbiome disruption. Consistent microbiome composition and recruitment is indicative that P. globosa microbiomes are stable-state systems undergoing deterministic community assembly and suggests there are specific, beneficial interactions between Phaeocystis and bacteria. Growth experiments with axenic and nonaxenic cultures demonstrated that microbiomes allowed continued growth when B-vitamins were withheld, but that microbiomes accelerated culture collapse when nitrogen was withheld. In sum, this study reveals symbiotic and opportunistic interactions between Phaeocystis colonies and microbiome bacteria that could influence large-scale phytoplankton bloom dynamics and biogeochemical cycles.
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Affiliation(s)
- Margaret Mars Brisbin
- Marine Biophysics Unit, Okinawa Institute of Science and Technology, Okinawa, Japan.
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
| | - Satoshi Mitarai
- Marine Biophysics Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Mak A Saito
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Harriet Alexander
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
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32
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Mathesius U. Are legumes different? Origins and consequences of evolving nitrogen fixing symbioses. JOURNAL OF PLANT PHYSIOLOGY 2022; 276:153765. [PMID: 35952452 DOI: 10.1016/j.jplph.2022.153765] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/01/2022] [Accepted: 07/03/2022] [Indexed: 05/14/2023]
Abstract
Nitrogen fixing symbioses between plants and bacteria are ancient and, while not numerous, are formed in diverse lineages of plants ranging from microalgae to angiosperms. One symbiosis stands out as the most widespread one is that between legumes and rhizobia, leading to the formation of nitrogen-fixing nodules. The legume family is one of the largest and most diverse group of plants and legumes have been used by humans since the beginning of agriculture, both as high nitrogen food, as well as pastures and rotation crops. One open question is whether their ability to form a nitrogen-fixing symbiosis has contributed to legumes' success, and whether legumes have any unique characteristics that have made them more diverse and widespread than other groups of plants. This review examines the evolutionary journey that has led to the diversification of legumes, in particular its nitrogen-fixing symbiosis, and asks four questions to investigate which legume traits might have contributed to their success: 1. In what ways do legumes differ from other plant groups that have evolved nitrogen-fixing symbioses? In order to answer this question, the characteristics of the symbioses, and efficiencies of nitrogen fixation are compared between different groups of nitrogen fixing plants. 2. Could certain unique features of legumes be a reason for their success? This section examines the manifestations and possible benefits of a nitrogen-rich 'lifestyle' in legumes. 3. If nitrogen fixation was a reason for such a success, why have some species lost the symbiosis? Formation of symbioses has trade-offs, and while these are less well known for non-legumes, there are known energetic and ecological reasons for loss of symbiotic potential in legumes. 4. What can we learn from the unique traits of legumes for future crop improvements? While exploiting some of the physiological properties of legumes could be used to improve legume breeding, our increasing molecular understanding of the essential regulators of root nodule symbioses raise hope of creating new nitrogen fixing symbioses in other crop species.
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Affiliation(s)
- Ulrike Mathesius
- Division of Plant Sciences, Research School of Biology, The Australian National University, 134 Linnaeus Way, Canberra, ACT, 2601, Australia.
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33
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Dundas CM, Dinneny JR. Genetic Circuit Design in Rhizobacteria. BIODESIGN RESEARCH 2022; 2022:9858049. [PMID: 37850138 PMCID: PMC10521742 DOI: 10.34133/2022/9858049] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 07/31/2022] [Indexed: 10/19/2023] Open
Abstract
Genetically engineered plants hold enormous promise for tackling global food security and agricultural sustainability challenges. However, construction of plant-based genetic circuitry is constrained by a lack of well-characterized genetic parts and circuit design rules. In contrast, advances in bacterial synthetic biology have yielded a wealth of sensors, actuators, and other tools that can be used to build bacterial circuitry. As root-colonizing bacteria (rhizobacteria) exert substantial influence over plant health and growth, genetic circuit design in these microorganisms can be used to indirectly engineer plants and accelerate the design-build-test-learn cycle. Here, we outline genetic parts and best practices for designing rhizobacterial circuits, with an emphasis on sensors, actuators, and chassis species that can be used to monitor/control rhizosphere and plant processes.
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Affiliation(s)
| | - José R. Dinneny
- Department of Biology, Stanford University, Stanford, CA 94305, USA
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34
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Korenblum E, Massalha H, Aharoni A. Plant-microbe interactions in the rhizosphere via a circular metabolic economy. THE PLANT CELL 2022; 34:3168-3182. [PMID: 35678568 PMCID: PMC9421461 DOI: 10.1093/plcell/koac163] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/25/2022] [Indexed: 05/30/2023]
Abstract
Chemical exchange often serves as the first step in plant-microbe interactions and exchanges of various signals, nutrients, and metabolites continue throughout the interaction. Here, we highlight the role of metabolite exchanges and metabolic crosstalk in the microbiome-root-shoot-environment nexus. Roots secret a diverse set of metabolites; this assortment of root exudates, including secondary metabolites such as benzoxazinoids, coumarins, flavonoids, indolic compounds, and terpenes, shapes the rhizosphere microbiome. In turn, the rhizosphere microbiome affects plant growth and defense. These inter-kingdom chemical interactions are based on a metabolic circular economy, a seemingly wasteless system in which rhizosphere members exchange (i.e. consume, reuse, and redesign) metabolites. This review also describes the recently discovered phenomenon "Systemically Induced Root Exudation of Metabolites" in which the rhizosphere microbiome governs plant metabolism by inducing systemic responses that shift the metabolic profiles of root exudates. Metabolic exchange in the rhizosphere is based on chemical gradients that form specific microhabitats for microbial colonization and we describe recently developed high-resolution methods to study chemical interactions in the rhizosphere. Finally, we propose an action plan to advance the metabolic circular economy in the rhizosphere for sustainable solutions to the cumulative degradation of soil health in agricultural lands.
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Affiliation(s)
- Elisa Korenblum
- Institute of Plant Science, Agricultural Research Organization, The Volcani Center, Rishon LeTsiyon 7528809, Israel
| | - Hassan Massalha
- Theory of Condensed Matter Group, Cavendish Laboratory, Wellcome Sanger Institute, University of Cambridge, Cambridge CB2 1TN, UK
| | - Asaph Aharoni
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
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35
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Orozco-Mosqueda MDC, Fadiji AE, Babalola OO, Glick BR, Santoyo G. Rhizobiome engineering: Unveiling complex rhizosphere interactions to enhance plant growth and health. Microbiol Res 2022; 263:127137. [PMID: 35905581 DOI: 10.1016/j.micres.2022.127137] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 06/17/2022] [Accepted: 07/13/2022] [Indexed: 12/13/2022]
Abstract
Crop plants are affected by a series of inhibitory environmental and biotic factors that decrease their growth and production. To counteract these adverse effects, plants work together with the microorganisms that inhabit their rhizosphere, which is part of the soil influenced by root exudates. The rhizosphere is a microecosystem where a series of complex interactions takes place between the resident microorganisms (rhizobiome) and plant roots. Therefore, this study analyzes the dynamics of plant-rhizobiome communication, the role of exudates (diffusible and volatile) as a factor in stimulating a diverse rhizobiome, and the differences between rhizobiomes of domesticated crops and wild plants. The study also analyzes different strategies to decipher the rhizobiome through both classical cultivation techniques and the so-called "omics" sciences. In addition, the rhizosphere engineering concept and the two general strategies to manipulate the rhizobiome, i.e., top down and bottom up engineering have been revisited. In addition, recent studies on the effects on the indigenous rhizobiome of inoculating plants with foreign strains, the impact on the endobiome, and the collateral effects on plant crops are discussed. Finally, understanding of the complex rhizosphere interactions and the biological repercussions of rhizobiome engineering as essential steps for improving plant growth and health is proposed, including under adverse conditions.
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Affiliation(s)
| | - Ayomide Emmanuel Fadiji
- Food Security and Safety Focus Area, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa
| | - Olubukola Oluranti Babalola
- Food Security and Safety Focus Area, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa
| | - Bernard R Glick
- Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Gustavo Santoyo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich 58030, Mexico.
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36
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Control of nitrogen fixation and ammonia excretion in Azorhizobium caulinodans. PLoS Genet 2022; 18:e1010276. [PMID: 35727841 PMCID: PMC9249168 DOI: 10.1371/journal.pgen.1010276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/01/2022] [Accepted: 05/26/2022] [Indexed: 11/19/2022] Open
Abstract
Due to the costly energy demands of nitrogen (N) fixation, diazotrophic bacteria have evolved complex regulatory networks that permit expression of the catalyst nitrogenase only under conditions of N starvation, whereas the same condition stimulates upregulation of high-affinity ammonia (NH3) assimilation by glutamine synthetase (GS), preventing excess release of excess NH3 for plants. Diazotrophic bacteria can be engineered to excrete NH3 by interference with GS, however control is required to minimise growth penalties and prevent unintended provision of NH3 to non-target plants. Here, we tested two strategies to control GS regulation and NH3 excretion in our model cereal symbiont Azorhizobium caulinodans AcLP, a derivative of ORS571. We first attempted to recapitulate previous work where mutation of both PII homologues glnB and glnK stimulated GS shutdown but found that one of these genes was essential for growth. Secondly, we expressed unidirectional adenylyl transferases (uATs) in a ΔglnE mutant of AcLP which permitted strong GS shutdown and excretion of NH3 derived from N2 fixation and completely alleviated negative feedback regulation on nitrogenase expression. We placed a uAT allele under control of the NifA-dependent promoter PnifH, permitting GS shutdown and NH3 excretion specifically under microaerobic conditions, the same cue that initiates N2 fixation, then deleted nifA and transferred a rhizopine nifAL94Q/D95Q-rpoN controller plasmid into this strain, permitting coupled rhizopine-dependent activation of N2 fixation and NH3 excretion. This highly sophisticated and multi-layered control circuitry brings us a step closer to the development of a "synthetic symbioses” where N2 fixation and NH3 excretion could be specifically activated in diazotrophic bacteria colonising transgenic rhizopine producing cereals, targeting delivery of fixed N to the crop while preventing interaction with non-target plants. Inoculation of cereal crops with associative diazotrophic bacteria that convert atmospheric nitrogen (N2) into ammonia (NH3) could be used to sustainably improve delivery of nitrogen to crops. However, due to the costly energy demands of N2 fixation, bacteria restrict excess production of NH3 and release to the plants. Diazotrophs can be engineered for excess NH3 production and release, however genetic control is required to minimise growth penalties and prevent unintended provision of NH3 to non-target weed species. Here, we engineer coupled control of N2 fixation and NH3 release in response to the signalling molecule rhizopine supplemented in vitro. This control circuitry represents a prototype for the future development of a “synthetic symbiosis” where bacterial N2 fixation and NH3 excretion could be specifically activated following colonisation of transgenic rhizopine producing cereals in the field, minimising bacterial energy requirements and preventing provision of NH3 to non-target plants.
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Trivedi P, Batista BD, Bazany KE, Singh BK. Plant-microbiome interactions under a changing world: responses, consequences and perspectives. THE NEW PHYTOLOGIST 2022; 234:1951-1959. [PMID: 35118660 DOI: 10.1111/nph.18016] [Citation(s) in RCA: 128] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 01/19/2022] [Indexed: 05/07/2023]
Abstract
Climate change is increasing global temperatures and the frequency and severity of droughts in many regions. These anthropogenic stresses pose a significant threat to plant performance and crop production. The plant-associated microbiome modulates the impacts of biotic and abiotic stresses on plant fitness. However, climate change-induced alteration in composition and activities of plant microbiomes can affect host functions. Here, we highlight recent advancements in our understanding of the impact of climate change (warming and drought) on plant-microbiome interactions and on their ecological functions from genome to ecosystem scales. We identify knowledge gaps, propose new concepts and make recommendations for future research directions. It is proposed that in the short term (years to decades), the adaptation of plants to climate change is mainly driven by the plant microbiome, whereas in the long term (century to millennia), the adaptation of plants will be driven equally by eco-evolutionary interactions between the plant microbiome and its host. A better understanding of the response of the plant and its microbiome interactions to climate change and the ways in which microbiomes can mitigate the negative impacts will better inform predictions of climate change impacts on primary productivity and aid in developing management and policy tools to improve the resilience of plant systems.
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Affiliation(s)
- Pankaj Trivedi
- Microbiome Network and Department of Agricultural Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Bruna D Batista
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2751, Australia
| | - Kathryn E Bazany
- Microbiome Network and Department of Agricultural Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Brajesh K Singh
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, 2751, Australia
- Global Centre for Land-Based Innovation, Western Sydney University, Richmond, NSW, 2751, Australia
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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.
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Hu H, Chen Q, He J. The end of hunger: fertilizers, microbes and plant productivity. Microb Biotechnol 2022; 15:1050-1054. [PMID: 34767687 PMCID: PMC8966006 DOI: 10.1111/1751-7915.13973] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/01/2021] [Accepted: 11/02/2021] [Indexed: 11/05/2022] Open
Abstract
It is a grand challenge to ensure the food security for a predicted world population of exceeding 9.7 billion by 2050, especially in an era of global climate change, land degradation and biodiversity loss. Current agricultural productions are mainly relying on synthetic chemical fertilisers to boost plant productivity but have undesirable effects on the environment and soil biodiversity. A promising direction in sustainable agriculture is to harness naturally occurring processes of beneficial plant-associated microbiomes to ensure sustained crop production and global food security. Despite the significant progress made in the development of beneficial microbes as inoculants to enhance plant performance, challenges remain with the translation of knowledge of plant and soil microbiomes to successful microbial products in the agricultural sector. Here, we highlight how fertilizer technology should be renovated by harnessing microbiome-based innovations to promote plant productivity and contribute to the end of hunger.
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Affiliation(s)
- Hang‐Wei Hu
- School of Agriculture and FoodFaculty of Veterinary and Agricultural SciencesThe University of MelbourneParkvilleVic.3010Australia
- ARC Hub for Smart FertilisersThe University of MelbourneParkvilleVic.3010Australia
| | - Qing‐Lin Chen
- School of Agriculture and FoodFaculty of Veterinary and Agricultural SciencesThe University of MelbourneParkvilleVic.3010Australia
| | - Ji‐Zheng He
- School of Agriculture and FoodFaculty of Veterinary and Agricultural SciencesThe University of MelbourneParkvilleVic.3010Australia
- ARC Hub for Smart FertilisersThe University of MelbourneParkvilleVic.3010Australia
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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.
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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
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41
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Connolly JA, Harcombe WR, Smanski MJ, Kinkel LL, Takano E, Breitling R. Harnessing intercellular signals to engineer the soil microbiome. Nat Prod Rep 2021; 39:311-324. [PMID: 34850800 DOI: 10.1039/d1np00034a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Covering: Focus on 2015 to 2020Plant and soil microbiomes consist of diverse communities of organisms from across kingdoms and can profoundly affect plant growth and health. Natural product-based intercellular signals govern important interactions between microbiome members that ultimately regulate their beneficial or harmful impacts on the plant. Exploiting these evolved signalling circuits to engineer microbiomes towards beneficial interactions with crops is an attractive goal. There are few reports thus far of engineering the intercellular signalling of microbiomes, but this article argues that it represents a tremendous opportunity for advancing the field of microbiome engineering. This could be achieved through the selection of synergistic consortia in combination with genetic engineering of signal pathways to realise an optimised microbiome.
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Affiliation(s)
- Jack A Connolly
- Manchester Institute of Biotechnology, Manchester Synthetic Biology Research Centre SYNBIOCHEM, Faculty of Science and Engineering, School of Natural Sciences, Department of Chemistry, The University of Manchester, Manchester, M1 7DN, UK.
| | - William R Harcombe
- BioTechnology Institute, University of Minnesota, Twin-Cities, Saint Paul, MN55108, USA.,Department of Evolution, and Behaviour, University of Minnesota, Twin-Cities Saint Paul, MN55108, USA
| | - Michael J Smanski
- BioTechnology Institute, University of Minnesota, Twin-Cities, Saint Paul, MN55108, USA.,Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Twin-Cities, Saint Paul, MN55108, USA
| | - Linda L Kinkel
- BioTechnology Institute, University of Minnesota, Twin-Cities, Saint Paul, MN55108, USA.,Department of Plant Pathology, University of Minnesota, Twin-Cities, Saint Paul, MN 55108, USA
| | - Eriko Takano
- Manchester Institute of Biotechnology, Manchester Synthetic Biology Research Centre SYNBIOCHEM, Faculty of Science and Engineering, School of Natural Sciences, Department of Chemistry, The University of Manchester, Manchester, M1 7DN, UK.
| | - Rainer Breitling
- Manchester Institute of Biotechnology, Manchester Synthetic Biology Research Centre SYNBIOCHEM, Faculty of Science and Engineering, School of Natural Sciences, Department of Chemistry, The University of Manchester, Manchester, M1 7DN, UK.
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Yu RP, Lambers H, Callaway RM, Wright AJ, Li L. Belowground facilitation and trait matching: two or three to tango? TRENDS IN PLANT SCIENCE 2021; 26:1227-1235. [PMID: 34400074 DOI: 10.1016/j.tplants.2021.07.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 07/15/2021] [Accepted: 07/24/2021] [Indexed: 05/12/2023]
Abstract
High biodiversity increases ecosystem functions; however, belowground facilitation remains poorly understood in this context. Here, we explore mechanisms that operate via 'giving-receiving feedbacks' for belowground facilitation. These include direct effects via root exudates, signals, and root trait plasticity, and indirect biotic facilitation via the effects of root exudates on soil biota and feedback from biota to plants. We then highlight that these two- or three-way mechanisms must affect biodiversity-ecosystem function relationships via specific combinations of matching traits. To tango requires a powerful affinity and harmony between well-matched partners, and such matches link belowground facilitation to the effect of biodiversity on function. Such matching underpins applications in intercropping, forestry, and pasture systems, in which diversity contributes to greater productivity and sustainability.
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Affiliation(s)
- Rui-Peng Yu
- Key Laboratory of Plant-Soil Interactions, Ministry of Education, Beijing Key Laboratory of Biodiversity and Organic Farming, College of Resources and Environmental Sciences, China Agricultural University, 2 Yuan Ming Yuan West Road, Beijing 100193, PR China
| | - Hans Lambers
- School of Biological Sciences and Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA 6009, Australia; National Academy of Agriculture Green Development, China Agricultural University, 2 Yuan Ming Yuan West Road, Beijing 100193, PR China
| | - Ragan M Callaway
- Division of Biological Sciences and Institute on Ecosystems, University of Montana, 32 Campus Drive, Missoula, MT 59812, USA
| | - Alexandra J Wright
- Department of Biological Sciences, California State University Los Angeles, 5151 State University Drive, Los Angeles, CA 90032, USA
| | - Long Li
- Key Laboratory of Plant-Soil Interactions, Ministry of Education, Beijing Key Laboratory of Biodiversity and Organic Farming, College of Resources and Environmental Sciences, China Agricultural University, 2 Yuan Ming Yuan West Road, Beijing 100193, PR China.
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Schnabel T, Sattely E. Improved Stability of Engineered Ammonia Production in the Plant-Symbiont Azospirillum brasilense. ACS Synth Biol 2021; 10:2982-2996. [PMID: 34591447 PMCID: PMC8604774 DOI: 10.1021/acssynbio.1c00287] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bioavailable nitrogen is the limiting nutrient for most agricultural food production. Associative diazotrophs can colonize crop roots and fix their own bioavailable nitrogen from the atmosphere. Wild-type (WT) associative diazotrophs, however, do not release fixed nitrogen in culture and are not known to directly transfer fixed nitrogen resources to plants. Efforts to engineer diazotrophs for plant nitrogen provision as an alternative to chemical fertilization have yielded several strains that transiently release ammonia. However, these strains suffer from selection pressure for nonproducers, which rapidly deplete ammonia accumulating in culture, likely limiting their potential for plant growth promotion (PGP). Here we report engineered Azospirillum brasilense strains with significantly extend ammonia production lifetimes of up to 32 days in culture. Our approach relies on multicopy genetic redundancy of a unidirectional adenylyltransferase (uAT) as a posttranslational mechanism to induce ammonia release via glutamine synthetase deactivation. Testing our multicopy stable strains with the model monocot Setaria viridis in hydroponic monoassociation reveals improvement in plant growth promotion compared to single copy strains. In contrast, inoculation of Zea mays in nitrogen-poor, nonsterile soil does not lead to increased PGP relative to WT, suggesting strain health, resource competition, or colonization capacity in soil may also be limiting factors. In this context, we show that while engineered strains fix more nitrogen per cell compared to WT strains, the expression strength of multiple uAT copies needs to be carefully balanced to maximize ammonia production rates and avoid excessive fitness defects caused by excessive glutamine synthetase shutdown.
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Affiliation(s)
- Tim Schnabel
- Department of Bioengineering, Stanford University, Stanford, California 94305, United States
| | - Elizabeth Sattely
- Department of Chemical Engineering, Stanford University and HHMI, Stanford, California 94305, United States
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Xun W, Shao J, Shen Q, Zhang R. Rhizosphere microbiome: Functional compensatory assembly for plant fitness. Comput Struct Biotechnol J 2021; 19:5487-5493. [PMID: 34712394 PMCID: PMC8515068 DOI: 10.1016/j.csbj.2021.09.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 09/29/2021] [Accepted: 09/29/2021] [Indexed: 01/13/2023] Open
Abstract
Environmental pressure to reduce our reliance on agrochemicals and the necessity to increase crop production in a sustainable way have made the rhizosphere microbiome an untapped resource for combating challenges to agricultural sustainability. In recent years, substantial efforts to characterize the structural and functional diversity of rhizosphere microbiomes of the model plant Arabidopsis thaliana and various crops have demonstrated their importance for plant fitness. However, the plant benefiting mechanisms of the rhizosphere microbiome as a whole community rather than as an individual rhizobacterium have only been revealed in recent years. The underlying principle dominating the assembly of the rhizosphere microbiome remains to be elucidated, and we are still struggling to harness the rhizosphere microbiome for agricultural sustainability. In this review, we summarize the recent progress of the driving factors shaping the rhizosphere microbiome and provide community-level mechanistic insights into the benefits that the rhizosphere microbiome has for plant fitness. We then propose the functional compensatory principle underlying rhizosphere microbiome assembly. Finally, we suggest future research efforts to explore the rhizosphere microbiome for agricultural sustainability.
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Affiliation(s)
- Weibing Xun
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, PR China
| | - Jiahui Shao
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, PR China
| | - Qirong Shen
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, PR China
| | - Ruifu Zhang
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Nanjing Agricultural University, Nanjing 210095, Jiangsu, PR China
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China
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Mendoza-Suárez M, Andersen SU, Poole PS, Sánchez-Cañizares C. Competition, Nodule Occupancy, and Persistence of Inoculant Strains: Key Factors in the Rhizobium-Legume Symbioses. FRONTIERS IN PLANT SCIENCE 2021; 12:690567. [PMID: 34489993 PMCID: PMC8416774 DOI: 10.3389/fpls.2021.690567] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 07/19/2021] [Indexed: 05/06/2023]
Abstract
Biological nitrogen fixation by Rhizobium-legume symbioses represents an environmentally friendly and inexpensive alternative to the use of chemical nitrogen fertilizers in legume crops. Rhizobial inoculants, applied frequently as biofertilizers, play an important role in sustainable agriculture. However, inoculants often fail to compete for nodule occupancy against native rhizobia with inferior nitrogen-fixing abilities, resulting in low yields. Strains with excellent performance under controlled conditions are typically selected as inoculants, but the rates of nodule occupancy compared to native strains are rarely investigated. Lack of persistence in the field after agricultural cycles, usually due to the transfer of symbiotic genes from the inoculant strain to naturalized populations, also limits the suitability of commercial inoculants. When rhizobial inoculants are based on native strains with a high nitrogen fixation ability, they often have superior performance in the field due to their genetic adaptations to the local environment. Therefore, knowledge from laboratory studies assessing competition and understanding how diverse strains of rhizobia behave, together with assays done under field conditions, may allow us to exploit the effectiveness of native populations selected as elite strains and to breed specific host cultivar-rhizobial strain combinations. Here, we review current knowledge at the molecular level on competition for nodulation and the advances in molecular tools for assessing competitiveness. We then describe ongoing approaches for inoculant development based on native strains and emphasize future perspectives and applications using a multidisciplinary approach to ensure optimal performance of both symbiotic partners.
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Affiliation(s)
| | - Stig U. Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Philip S. Poole
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
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Chialva M, Lanfranco L, Bonfante P. The plant microbiota: composition, functions, and engineering. Curr Opin Biotechnol 2021; 73:135-142. [PMID: 34392234 DOI: 10.1016/j.copbio.2021.07.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/03/2021] [Accepted: 07/05/2021] [Indexed: 11/03/2022]
Abstract
Plants growing in nature live in association with beneficial, commensal, and pathogenic microbes, which make up the plant microbiota. The close interaction between plants and their microbiotas has raised fundamental questions about plant responses to these microbes and the identity of the main factors driving microbiota structure, diversity, and function in bulk soil, in the rhizosphere, and in the plant organs. Beneficial microorganisms have long been used as inoculants for crops; the current development of synthetic microbial communities and the identification of plant traits that respond to the microbiota form the basis for rational engineering of the plant microbiota to improve sustainable agriculture.
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Affiliation(s)
- Matteo Chialva
- Department of Life Sciences and Systems Biology, University of Torino, Viale P.A. Mattioli 25, I-10125 Torino, Italy; Department of Agricultural, Forest and Food Sciences, University of Torino, Largo P. Braccini 2, 10095 Grugliasco (TO), Italy
| | - Luisa Lanfranco
- Department of Life Sciences and Systems Biology, University of Torino, Viale P.A. Mattioli 25, I-10125 Torino, Italy
| | - Paola Bonfante
- Department of Life Sciences and Systems Biology, University of Torino, Viale P.A. Mattioli 25, I-10125 Torino, Italy.
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Yukun G, Jianghui C, Genzeng R, Shilin W, Puyuan Y, Congpei Y, Hongkai L, Jinhua C. Changes in the root-associated bacteria of sorghum are driven by the combined effects of salt and sorghum development. ENVIRONMENTAL MICROBIOME 2021; 16:14. [PMID: 34380546 PMCID: PMC8356455 DOI: 10.1186/s40793-021-00383-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 06/10/2021] [Indexed: 05/05/2023]
Abstract
BACKGROUND Sorghum is an important food staple in the developing world, with the capacity to grow under severe conditions such as salinity, drought, and a limited nutrient supply. As a serious environmental stress, soil salinization can change the composition of rhizosphere soil bacterial communities and induce a series of harm to crops. And the change of rhizospheric microbes play an important role in the response of plants to salt stress. However, the effect of salt stress on the root bacteria of sorghum and interactions between bacteria and sorghum remains poorly understood. RESULTS The purpose of this study was to assess the effect of salt stress on sorghum growth performance and rhizosphere bacterial community structure. Statistical analysis confirmed that low high concentration stress depressed sorghum growth. Further taxonomic analysis revealed that the bacterial community predominantly consisted of phyla Proteobacteria, Actinobacteria, Acidobacteria, Chloroflexi, Bacteroidetes and Firmicutes in sorghum rhizosphere soil. Low salt stress suppressed the development of bacterial diversity less than high salt stress in both bulk soil and planted sorghum soil. Different sorghum development stages in soils with different salt concentrations enriched distinctly different members of the root bacteria. No obviously different effect on bacterial diversity were tested by PERMANOVA analysis between different varieties, but interactions between salt and growth and between salt and variety were detected. The roots of sorghum exuded phenolic compounds that differed among the different varieties and had a significant relationship with rhizospheric bacterial diversity. These results demonstrated that salt and sorghum planting play important roles in restructuring the bacteria in rhizospheric soil. Salinity and sorghum variety interacted to affect bacterial diversity. CONCLUSIONS In this paper, we found that salt variability and planting are key factors in shifting bacterial diversity and community. In comparison to bulk soils, soils under planting sorghum with different salt stress levels had a characteristic bacterial environment. Salinity and sorghum variety interacted to affect bacterial diversity. Different sorghum variety with different salt tolerance levels had different responses to salt stress by regulating root exudation. Soil bacterial community responses to salinity and exotic plants could potentially impact the microenvironment to help plants overcome external stressors and promote sorghum growth. While this study observed bacterial responses to combined effects of salt and sorghum development, future studies are needed to understand the interaction among bacteria communities, salinity, and sorghum growth.
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Affiliation(s)
- Gao Yukun
- College of Agronomy, Hebei Agricultural University, Northern China Key Laboratory for Crop Germplasm Resources of Education Ministry, No. 2596 LeKai South Street, Baoding, Hebei China
| | - Cui Jianghui
- College of Agronomy, Hebei Agricultural University, Northern China Key Laboratory for Crop Germplasm Resources of Education Ministry, No. 2596 LeKai South Street, Baoding, Hebei China
| | - Ren Genzeng
- College of Agronomy, Hebei Agricultural University, Northern China Key Laboratory for Crop Germplasm Resources of Education Ministry, No. 2596 LeKai South Street, Baoding, Hebei China
| | - Wei Shilin
- College of Agronomy, Hebei Agricultural University, Northern China Key Laboratory for Crop Germplasm Resources of Education Ministry, No. 2596 LeKai South Street, Baoding, Hebei China
| | - Yang Puyuan
- College of Agronomy, Hebei Agricultural University, Northern China Key Laboratory for Crop Germplasm Resources of Education Ministry, No. 2596 LeKai South Street, Baoding, Hebei China
| | - Yin Congpei
- College of Agronomy, Hebei Agricultural University, Northern China Key Laboratory for Crop Germplasm Resources of Education Ministry, No. 2596 LeKai South Street, Baoding, Hebei China
| | - Liang Hongkai
- College of Agronomy, Hebei Agricultural University, Northern China Key Laboratory for Crop Germplasm Resources of Education Ministry, No. 2596 LeKai South Street, Baoding, Hebei China
| | - Chang Jinhua
- College of Agronomy, Hebei Agricultural University, Northern China Key Laboratory for Crop Germplasm Resources of Education Ministry, No. 2596 LeKai South Street, Baoding, Hebei China
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Schnabel T, Sattely E. Engineering Posttranslational Regulation of Glutamine Synthetase for Controllable Ammonia Production in the Plant Symbiont Azospirillum brasilense. Appl Environ Microbiol 2021; 87:e0058221. [PMID: 33962983 PMCID: PMC8231714 DOI: 10.1128/aem.00582-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 04/27/2021] [Indexed: 11/20/2022] Open
Abstract
Nitrogen requirements for modern agriculture far exceed the levels of bioavailable nitrogen in most arable soils. As a result, the addition of nitrogen fertilizer is necessary to sustain productivity and yields, especially for cereal crops, the planet's major calorie suppliers. Given the unsustainability of industrial fertilizer production and application, engineering biological nitrogen fixation directly at the roots of plants has been a grand challenge for biotechnology. Here, we designed and tested a potentially broadly applicable metabolic engineering strategy for the overproduction of ammonia in the diazotrophic symbiont Azospirillum brasilense. Our approach is based on an engineered unidirectional adenylyltransferase (uAT) that posttranslationally modifies and deactivates glutamine synthetase (GS), a key regulator of nitrogen metabolism in the cell. We show that this circuit can be controlled inducibly, and we leveraged the inherent self-contained nature of our posttranslational approach to demonstrate that multicopy redundancy can improve strain evolutionary stability. uAT-engineered Azospirillum is capable of producing ammonia at rates of up to 500 μM h-1 unit of OD600 (optical density at 600 nm)-1. We demonstrated that when grown in coculture with the model monocot Setaria viridis, these strains increase the biomass and chlorophyll content of plants up to 54% and 71%, respectively, relative to the wild type (WT). Furthermore, we rigorously demonstrated direct transfer of atmospheric nitrogen to extracellular ammonia and then plant biomass using isotopic labeling: after 14 days of cocultivation with engineered uAT strains, 9% of chlorophyll nitrogen in Setaria seedlings was derived from diazotrophically fixed dinitrogen, whereas no nitrogen was incorporated in plants cocultivated with WT controls. This rational design for tunable ammonia overproduction is modular and flexible, and we envision that it could be deployable in a consortium of nitrogen-fixing symbiotic diazotrophs for plant fertilization. IMPORTANCE Nitrogen is the most limiting nutrient in modern agriculture. Free-living diazotrophs, such as Azospirillum, are common colonizers of cereal grasses and have the ability to fix nitrogen but natively do not release excess ammonia. Here, we used a rational engineering approach to generate ammonia-excreting strains of Azospirillum. Our design features posttranslational control of highly conserved central metabolism, enabling tunability and flexibility of circuit placement. We found that our strains promote the growth and health of the model grass S. viridis and rigorously demonstrated that in comparison to WT controls, our engineered strains can transfer nitrogen from 15N2 gas to plant biomass. Unlike previously reported ammonia-producing mutants, our rationally designed approach easily lends itself to further engineering opportunities and has the potential to be broadly deployable.
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Affiliation(s)
- Tim Schnabel
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Elizabeth Sattely
- Department of Chemical Engineering, Stanford University and HHMI, Stanford, California, USA
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Haskett TL, Knights HE, Jorrin B, Mendes MD, Poole PS. A Simple in situ Assay to Assess Plant-Associative Bacterial Nitrogenase Activity. Front Microbiol 2021; 12:690439. [PMID: 34248916 PMCID: PMC8261070 DOI: 10.3389/fmicb.2021.690439] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 05/25/2021] [Indexed: 11/23/2022] Open
Abstract
Assessment of plant-associative bacterial nitrogen (N) fixation is crucial for selection and development of elite diazotrophic inoculants that could be used to supply cereal crops with nitrogen in a sustainable manner. Although diazotrophic bacteria possess diverse oxygen tolerance mechanisms, most require a sub 21% oxygen environment to achieve optimal stability and function of the N-fixing catalyst nitrogenase. Consequently, assessment of N fixation is routinely carried out on “free-living” bacteria grown in the absence of a host plant and such experiments may not accurately divulge activity in the rhizosphere where the availability and forms of nutrients such as carbon and N, which are key regulators of N fixation, may vary widely. Here, we present a modified in situ acetylene reduction assay (ARA), utilizing the model cereal barley as a host to comparatively assess nitrogenase activity in diazotrophic bacteria. The assay is rapid, highly reproducible, applicable to a broad range of diazotrophs, and can be performed with simple equipment commonly found in most laboratories that investigate plant-microbe interactions. Thus, the assay could serve as a first point of order for high-throughput identification of elite plant-associative diazotrophs.
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Affiliation(s)
- Timothy L Haskett
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Hayley E Knights
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Beatriz Jorrin
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Marta D Mendes
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Philip S Poole
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
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50
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Liang Y, Liu HJ, Yan J, Tian F. Natural Variation in Crops: Realized Understanding, Continuing Promise. ANNUAL REVIEW OF PLANT BIOLOGY 2021; 72:357-385. [PMID: 33481630 DOI: 10.1146/annurev-arplant-080720-090632] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Crops feed the world's population and shape human civilization. The improvement of crop productivity has been ongoing for almost 10,000 years and has evolved from an experience-based to a knowledge-driven practice over the past three decades. Natural alleles and their reshuffling are long-standing genetic changes that affect how crops respond to various environmental conditions and agricultural practices. Decoding the genetic basis of natural variation is central to understanding crop evolution and, in turn, improving crop breeding. Here, we review current advances in the approaches used to map the causal alleles of natural variation, provide refined insights into the genetics and evolution of natural variation, and outline how this knowledge promises to drive the development of sustainable agriculture under the dome of emerging technologies.
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Affiliation(s)
- Yameng Liang
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Key Laboratory of Biology and Genetic Improvement of Maize (MOA), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, China; ,
| | - Hai-Jun Liu
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, 1030 Vienna, Austria;
| | - Jianbing Yan
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China;
| | - Feng Tian
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Key Laboratory of Biology and Genetic Improvement of Maize (MOA), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, China; ,
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