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Huang W, Wang D, Zhang XX, Zhao M, Sun L, Zhou Y, Guan X, Xie Z. Regulatory roles of the second messenger c-di-GMP in beneficial plant-bacteria interactions. Microbiol Res 2024; 285:127748. [PMID: 38735241 DOI: 10.1016/j.micres.2024.127748] [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: 10/11/2023] [Revised: 05/02/2024] [Accepted: 05/03/2024] [Indexed: 05/14/2024]
Abstract
The rhizosphere system of plants hosts a diverse consortium of bacteria that confer beneficial effects on plant, such as plant growth-promoting rhizobacteria (PGPR), biocontrol agents with disease-suppression activities, and symbiotic nitrogen fixing bacteria with the formation of root nodule. Efficient colonization in planta is of fundamental importance for promoting of these beneficial activities. However, the process of root colonization is complex, consisting of multiple stages, including chemotaxis, adhesion, aggregation, and biofilm formation. The secondary messenger, c-di-GMP (cyclic bis-(3'-5') dimeric guanosine monophosphate), plays a key regulatory role in a variety of physiological processes. This paper reviews recent progress on the actions of c-di-GMP in plant beneficial bacteria, with a specific focus on its role in chemotaxis, biofilm formation, and nodulation.
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Affiliation(s)
- Weiwei Huang
- National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Taian, Shandong Province 271018, China
| | - Dandan Wang
- National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Taian, Shandong Province 271018, China
| | - Xue-Xian Zhang
- School of Natural Sciences, Massey University at Albany, Auckland 0745, New Zealand
| | - Mengguang Zhao
- National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Taian, Shandong Province 271018, China
| | - Li Sun
- National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Taian, Shandong Province 271018, China
| | - Yanan Zhou
- National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Taian, Shandong Province 271018, China
| | - Xin Guan
- National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Taian, Shandong Province 271018, China
| | - Zhihong Xie
- National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Taian, Shandong Province 271018, China.
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2
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Pradeu T, Thomma BPHJ, Girardin SE, Lemaitre B. The conceptual foundations of innate immunity: Taking stock 30 years later. Immunity 2024; 57:613-631. [PMID: 38599162 DOI: 10.1016/j.immuni.2024.03.007] [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: 01/14/2024] [Revised: 02/23/2024] [Accepted: 03/06/2024] [Indexed: 04/12/2024]
Abstract
While largely neglected over decades during which adaptive immunity captured most of the attention, innate immune mechanisms have now become central to our understanding of immunology. Innate immunity provides the first barrier to infection in vertebrates, and it is the sole mechanism of host defense in invertebrates and plants. Innate immunity also plays a critical role in maintaining homeostasis, shaping the microbiota, and in disease contexts such as cancer, neurodegeneration, metabolic syndromes, and aging. The emergence of the field of innate immunity has led to an expanded view of the immune system, which is no longer restricted to vertebrates and instead concerns all metazoans, plants, and even prokaryotes. The study of innate immunity has given rise to new concepts and language. Here, we review the history and definition of the core concepts of innate immunity, discussing their value and fruitfulness in the long run.
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Affiliation(s)
- Thomas Pradeu
- CNRS UMR 5164 ImmunoConcept, University of Bordeaux, Bordeaux, France; Department of Biological and Medical Sciences, University of Bordeaux, Bordeaux, France; Presidential Fellow, Chapman University, Orange, CA, USA.
| | - Bart P H J Thomma
- Institute for Plant Sciences, University of Cologne, Cologne, Germany
| | - Stephen E Girardin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Bruno Lemaitre
- Global Health Institute, School of Life Science, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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3
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Ayala-García P, Jiménez-Guerrero I, Müsken M, Ollero FJ, Borrero-De Acuña JM, Pérez-Montaño F. Isolation of Rhizobial Extracellular Membrane Vesicles from Bacteroids. Methods Mol Biol 2024; 2751:229-236. [PMID: 38265720 DOI: 10.1007/978-1-0716-3617-6_15] [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: 01/25/2024]
Abstract
Extracellular-membrane vesicles (EMVs) are spherical buds of the extracellular membrane, commonly produced by Gram-negative bacteria, known to mediate intricate inter-kingdom communication. In this context, comprehensive research dissecting the role of EMVs in one of the most complex nature-occurring molecular dialogues, rhizobium-legume symbiosis, has been so far neglected. During the different stages of the symbiotic process, rhizobia and their host plants establish a very specific and controlled intercellular trafficking of signal molecules. Thus, as conveyors of a broad range of molecules into the target cell, EMVs are gaining weight in the field. Here, we describe a detailed protocol to isolate EMVs from bacteroids of legume nodules, opening a new door for discovering new authors of the symbiotic process.
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Affiliation(s)
| | | | - Mathias Müsken
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, Braunschweig, Germany
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4
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Sharma S, Ganotra J, Samantaray J, Sahoo RK, Bhardwaj D, Tuteja N. An emerging role of heterotrimeric G-proteins in nodulation and nitrogen sensing. PLANTA 2023; 258:101. [PMID: 37847414 DOI: 10.1007/s00425-023-04251-8] [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: 02/28/2023] [Accepted: 09/25/2023] [Indexed: 10/18/2023]
Abstract
MAIN CONCLUSION A comprehensive understanding of nitrogen signaling cascades involving heterotrimeric G-proteins and their putative receptors can assist in the production of nitrogen-efficient plants. Plants are immobile in nature, so they must endure abiotic stresses including nutrient stress. Plant development and agricultural productivity are frequently constrained by the restricted availability of nitrogen in the soil. Non-legume plants acquire nitrogen from the soil through root membrane-bound transporters. In depleted soil nitrogen conditions, legumes are naturally conditioned to fix atmospheric nitrogen with the aid of nodulation elicited by nitrogen-fixing bacteria. Moreover, apart from the symbiotic nitrogen fixation process, nitrogen uptake from the soil can also be a significant secondary source to satisfy the nitrogen requirements of legumes. Heterotrimeric G-proteins function as molecular switches to help plant cells relay diverse stimuli emanating from external stress conditions. They are comprised of Gα, Gβ and Gγ subunits, which cooperate with several downstream effectors to regulate multiple plant signaling events. In the present review, we concentrate on signaling mechanisms that regulate plant nitrogen nutrition. Our review highlights the potential of heterotrimeric G-proteins, together with their putative receptors, to assist the legume root nodule symbiosis (RNS) cascade, particularly during calcium spiking and nodulation. Additionally, the functions of heterotrimeric G-proteins in nitrogen acquisition by plant roots as well as in improving nitrogen use efficiency (NUE) have also been discussed. Future research oriented towards heterotrimeric G-proteins through genome editing tools can be a game changer in the enhancement of the nitrogen fixation process. This will foster the precise manipulation and production of plants to ensure global food security in an era of climate change by enhancing crop productivity and minimizing reliance on external inputs.
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Affiliation(s)
- Suvriti Sharma
- Department of Botany, Central University of Jammu, Jammu, Jammu and Kashmir, 181143, India
| | - Jahanvi Ganotra
- Department of Botany, Central University of Jammu, Jammu, Jammu and Kashmir, 181143, India
| | - Jyotipriya Samantaray
- Department of Botany, Central University of Jammu, Jammu, Jammu and Kashmir, 181143, India
| | - Ranjan Kumar Sahoo
- Department of Biotechnology, Centurion University of Technology and Management, Bhubaneswar, Odisha, 752050, India
| | - Deepak Bhardwaj
- Department of Botany, Central University of Jammu, Jammu, Jammu and Kashmir, 181143, India.
| | - Narendra Tuteja
- Plant Molecular Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
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5
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Total Synthesis of the Methyl Glycoside of Bradyrhizose via Intramolecular Pinacol Coupling. Tetrahedron Lett 2022. [DOI: 10.1016/j.tetlet.2022.154060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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6
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Sun C. A rhizobial non-coding RNA has an effect on symbiotic nodulation by regulating an ABC transporter. Biochem Biophys Res Commun 2022; 603:82-87. [DOI: 10.1016/j.bbrc.2022.03.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 03/03/2022] [Indexed: 11/02/2022]
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7
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Pearson C, Tindall S, Potts JR, Thomas GH, van der Woude MW. Diverse functions for acyltransferase-3 proteins in the modification of bacterial cell surfaces. MICROBIOLOGY (READING, ENGLAND) 2022; 168:001146. [PMID: 35253642 PMCID: PMC9558356 DOI: 10.1099/mic.0.001146] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 01/21/2022] [Indexed: 12/27/2022]
Abstract
The acylation of sugars, most commonly via acetylation, is a widely used mechanism in bacteria that uses a simple chemical modification to confer useful traits. For structures like lipopolysaccharide, capsule and peptidoglycan, that function outside of the cytoplasm, their acylation during export or post-synthesis requires transport of an activated acyl group across the membrane. In bacteria this function is most commonly linked to a family of integral membrane proteins - acyltransferase-3 (AT3). Numerous studies examining production of diverse extracytoplasmic sugar-containing structures have identified roles for these proteins in O-acylation. Many of the phenotypes conferred by the action of AT3 proteins influence host colonisation and environmental survival, as well as controlling the properties of biotechnologically important polysaccharides and the modification of antibiotics and antitumour drugs by Actinobacteria. Herein we present the first systematic review, to our knowledge, of the functions of bacterial AT3 proteins, revealing an important protein family involved in a plethora of systems of importance to bacterial function that is still relatively poorly understood at the mechanistic level. By defining and comparing this set of functions we draw out common themes in the structure and mechanism of this fascinating family of membrane-bound enzymes, which, due to their role in host colonisation in many pathogens, could offer novel targets for the development of antimicrobials.
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Affiliation(s)
| | - Sarah Tindall
- Department of Biology, University of York, Heslington, UK
| | | | - Gavin H. Thomas
- Department of Biology, University of York, Heslington, UK
- York Biomedical Institute, University of York, Heslington, UK
| | - Marjan W. van der Woude
- York Biomedical Institute, University of York, Heslington, UK
- Hull York Medical School, Heslington, UK
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8
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Plant-Microbe Interaction in Sustainable Agriculture: The Factors That May Influence the Efficacy of PGPM Application. SUSTAINABILITY 2022. [DOI: 10.3390/su14042253] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The indiscriminate use of chemical fertilizers and pesticides has caused considerable environmental damage over the years. However, the growing demand for food in the coming years and decades requires the use of increasingly productive and efficient agriculture. Several studies carried out in recent years have shown how the application of plant growth-promoting microbes (PGPMs) can be a valid substitute for chemical industry products and represent a valid eco-friendly alternative. However, because of the complexity of interactions created with the numerous biotic and abiotic factors (i.e., environment, soil, interactions between microorganisms, etc.), the different formulates often show variable effects. In this review, we analyze the main factors that influence the effectiveness of PGPM applications and some of the applications that make them a useful tool for agroecological transition.
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9
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Basile LA, Lepek VC. Legume-rhizobium dance: an agricultural tool that could be improved? Microb Biotechnol 2021; 14:1897-1917. [PMID: 34318611 PMCID: PMC8449669 DOI: 10.1111/1751-7915.13906] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 07/15/2021] [Accepted: 07/19/2021] [Indexed: 12/29/2022] Open
Abstract
The specific interaction between rhizobia and legume roots leads to the development of a highly regulated process called nodulation, by which the atmospheric nitrogen is converted into an assimilable plant nutrient. This capacity is the basis for the use of bacterial inoculants for field crop cultivation. Legume plants have acquired tools that allow the entry of compatible bacteria. Likewise, plants can impose sanctions against the maintenance of nodules occupied by rhizobia with low nitrogen-fixing capacity. At the same time, bacteria must overcome different obstacles posed first by the environment and then by the legume. The present review describes the mechanisms involved in the regulation of the entire legume-rhizobium symbiotic process and the strategies and tools of bacteria for reaching the nitrogen-fixing state inside the nodule. Also, we revised different approaches to improve the nodulation process for a better crop yield.
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Affiliation(s)
- Laura A. Basile
- Instituto de Investigaciones Biotecnológicas “Dr. Rodolfo A. Ugalde”Universidad Nacional de San Martín (IIB‐UNSAM‐CONICET)Av. 25 de Mayo y Francia, Gral. San Martín, Provincia de Buenos AiresBuenos AiresB1650HMPArgentina
| | - Viviana C. Lepek
- Instituto de Investigaciones Biotecnológicas “Dr. Rodolfo A. Ugalde”Universidad Nacional de San Martín (IIB‐UNSAM‐CONICET)Av. 25 de Mayo y Francia, Gral. San Martín, Provincia de Buenos AiresBuenos AiresB1650HMPArgentina
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10
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Rolli E, Vergani L, Ghitti E, Patania G, Mapelli F, Borin S. 'Cry-for-help' in contaminated soil: a dialogue among plants and soil microbiome to survive in hostile conditions. Environ Microbiol 2021; 23:5690-5703. [PMID: 34139059 PMCID: PMC8596516 DOI: 10.1111/1462-2920.15647] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/25/2021] [Accepted: 06/16/2021] [Indexed: 12/20/2022]
Abstract
An open question in environmental ecology regards the mechanisms triggered by root chemistry to drive the assembly and functionality of a beneficial microbiome to rapidly adapt to stress conditions. This phenomenon, originally described in plant defence against pathogens and predators, is encompassed in the ‘cry‐for‐help’ hypothesis. Evidence suggests that this mechanism may be part of the adaptation strategy to ensure the holobiont fitness in polluted environments. Polychlorinated biphenyls (PCBs) were considered as model pollutants due to their toxicity, recalcitrance and poor phyto‐extraction potential, which lead to a plethora of phytotoxic effects and rise environmental safety concerns. Plants have inefficient detoxification processes to catabolize PCBs, even leading to by‐products with a higher toxicity. We propose that the ‘cry‐for‐help’ mechanism could drive the exudation‐mediated recruitment and sustainment of the microbial services for PCBs removal, exerted by an array of anaerobic and aerobic microbial degrading populations working in a complex metabolic network. Through this synergistic interaction, the holobiont copes with the soil contamination, releasing the plant from the pollutant stress by the ecological services provided by the boosted metabolism of PCBs microbial degraders. Improving knowledge of root chemistry under PCBs stress is, therefore, advocated to design rhizoremediation strategies based on plant microbiome engineering.
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Affiliation(s)
- Eleonora Rolli
- Department of Food, Environmental and Nutritional Sciences, DeFENS, University of Milan, Via Celoria 2, Milan, 20133, Italy
| | - Lorenzo Vergani
- Department of Food, Environmental and Nutritional Sciences, DeFENS, University of Milan, Via Celoria 2, Milan, 20133, Italy
| | - Elisa Ghitti
- Department of Food, Environmental and Nutritional Sciences, DeFENS, University of Milan, Via Celoria 2, Milan, 20133, Italy
| | - Giovanni Patania
- Department of Food, Environmental and Nutritional Sciences, DeFENS, University of Milan, Via Celoria 2, Milan, 20133, Italy
| | - Francesca Mapelli
- Department of Food, Environmental and Nutritional Sciences, DeFENS, University of Milan, Via Celoria 2, Milan, 20133, Italy
| | - Sara Borin
- Department of Food, Environmental and Nutritional Sciences, DeFENS, University of Milan, Via Celoria 2, Milan, 20133, Italy
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11
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Goyal RK, Mattoo AK, Schmidt MA. Rhizobial-Host Interactions and Symbiotic Nitrogen Fixation in Legume Crops Toward Agriculture Sustainability. Front Microbiol 2021; 12:669404. [PMID: 34177848 PMCID: PMC8226219 DOI: 10.3389/fmicb.2021.669404] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 04/29/2021] [Indexed: 11/13/2022] Open
Abstract
Symbiotic nitrogen fixation (SNF) process makes legume crops self-sufficient in nitrogen (N) in sharp contrast to cereal crops that require an external input by N-fertilizers. Since the latter process in cereal crops results in a huge quantity of greenhouse gas emission, the legume production systems are considered efficient and important for sustainable agriculture and climate preservation. Despite benefits of SNF, and the fact that chemical N-fertilizers cause N-pollution of the ecosystems, the focus on improving SNF efficiency in legumes did not become a breeder’s priority. The size and stability of heritable effects under different environment conditions weigh significantly on any trait useful in breeding strategies. Here we review the challenges and progress made toward decoding the heritable components of SNF, which is considerably more complex than other crop allelic traits since the process involves genetic elements of both the host and the symbiotic rhizobial species. SNF-efficient rhizobial species designed based on the genetics of the host and its symbiotic partner face the test of a unique microbiome for its success and productivity. The progress made thus far in commercial legume crops with relevance to the dynamics of host–rhizobia interaction, environmental impact on rhizobial performance challenges, and what collectively determines the SNF efficiency under field conditions are also reviewed here.
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Affiliation(s)
- Ravinder K Goyal
- Agriculture and Agri-Food Canada, Lacombe Research and Development Centre, Lacombe, AB, Canada
| | - Autar K Mattoo
- Sustainable Agricultural Systems Laboratory, Agricultural Research Service, United States Department of Agriculture, Beltsville Agricultural Research Center, Beltsville, MD, United States
| | - Maria Augusta Schmidt
- Agriculture and Agri-Food Canada, Lacombe Research and Development Centre, Lacombe, AB, Canada
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12
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Computational characterizations of GDP-mannose 4,6-dehydratase (NoeL) Rhizobial proteins. Curr Genet 2021; 67:769-784. [PMID: 33837815 DOI: 10.1007/s00294-021-01184-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/19/2021] [Accepted: 03/29/2021] [Indexed: 10/21/2022]
Abstract
A growing body of evidence suggests that Nod Factors molecules are the critical structural components in nitrogen fixation. These molecules have been implicated in plant-microbe signaling. Many enzymes involved in Nod factors biosynthesis; however, the enzymes that decorate (modify) nod factor main structure play a vital role. Here, the computational analysis of GDP-mannose 4,6-dehydratase (NoeL) proteins with great impact in modification of nod factor structure in four genomes of agriculturally important rhizobia (Bradyrhizobium, Mesorhizobium, Rhizobium, Sinorhizobium) presented. The NoeL number of amino acids was in the range of 147 (M5AMF5) to 372 (A0A023XWX0, Q89TZ1). The molecular weights were around 41 KDa. The results showed that the strain-specific purification strategy should apply as the pI of the sequences varied significantly (in the range of 5.59 to 9.12). The enzyme sequences and eight 3-dimensional structures predicted with homology modeling and machine learning representing the phylogenetic tree revealed the stability of enzymes in different conditions (Instability and Aliphatic index); however, this stability is also strain-specific. Disulphide bonds were observed in some species; however, the pattern was not detected in all members of the same species. Alpha helix was the dominant secondary structure predicted in all cytoplasmic NoeL. All models were homo-tetramer with acceptable sequence identity, GMEAN and coverage (60, - 1.80, 88, respectively). Additionally, Ramachandran maps showed that more than 94% of residues are in favored regions. We also highlight several key characterizations of NoeL from four rhizobia genomes annotation. These findings provide novel insights into the complexity and diversity of NoeL enzymes among important rhizobia and suggest considering a broader framework of biofilm for future research.
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13
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Pande A, Mun BG, Lee DS, Khan M, Lee GM, Hussain A, Yun BW. NO Network for Plant-Microbe Communication Underground: A Review. FRONTIERS IN PLANT SCIENCE 2021; 12:658679. [PMID: 33815456 PMCID: PMC8010196 DOI: 10.3389/fpls.2021.658679] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 02/24/2021] [Indexed: 05/30/2023]
Abstract
Mechanisms governing plant-microbe interaction in the rhizosphere attracted a lot of investigative attention in the last decade. The rhizosphere is not simply a source of nutrients and support for the plants; it is rather an ecosystem teeming with diverse flora and fauna including different groups of microbes that are useful as well as harmful for the plants. Plant-microbe interaction occurs via a highly complex communication network that involves sophisticated machinery for the recognition of friend and foe at both sides. On the other hand, nitric oxide (NO) is a key, signaling molecule involved in plant development and defense. Studies on legume-rhizobia symbiosis suggest the involvement of NO during recognition, root hair curling, development of infection threads, nodule development, and nodule senescence. A similar role of NO is also suggested in the case of plant interaction with the mycorrhizal fungi. Another, insight into the plant-microbe interaction in the rhizosphere comes from the recognition of pathogen-associated molecular patterns (PAMPs)/microbe-associated molecular patterns (MAMPs) by the host plant and thereby NO-mediated activation of the defense signaling cascade. Thus, NO plays a major role in mediating the communication between plants and microbes in the rhizosphere. Interestingly, reports suggesting the role of silicon in increasing the number of nodules, enhancing nitrogen fixation, and also the combined effect of silicon and NO may indicate a possibility of their interaction in mediating microbial communication underground. However, the exact role of NO in mediating plant-microbe interaction remains elusive. Therefore, understanding the role of NO in underground plant physiology is very important, especially in relation to the plant's interaction with the rhizospheric microbiome. This will help devise new strategies for protection against phytopathogens and enhancing plant productivity by promoting symbiotic interaction. This review focuses on the role of NO in plant-microbe communication underground.
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Affiliation(s)
- Anjali Pande
- Laboratory of Plant Molecular Pathology and Functional Genomics, Department of Plant Biosciences, School of Applied Biosciences, College of Agriculture and Life Science, Kyungpook National University, Daegu, South Korea
| | - Bong-Gyu Mun
- Laboratory of Plant Molecular Pathology and Functional Genomics, Department of Plant Biosciences, School of Applied Biosciences, College of Agriculture and Life Science, Kyungpook National University, Daegu, South Korea
| | - Da-Sol Lee
- Laboratory of Plant Molecular Pathology and Functional Genomics, Department of Plant Biosciences, School of Applied Biosciences, College of Agriculture and Life Science, Kyungpook National University, Daegu, South Korea
| | - Murtaza Khan
- Laboratory of Plant Molecular Pathology and Functional Genomics, Department of Plant Biosciences, School of Applied Biosciences, College of Agriculture and Life Science, Kyungpook National University, Daegu, South Korea
| | - Geun-Mo Lee
- Laboratory of Plant Molecular Pathology and Functional Genomics, Department of Plant Biosciences, School of Applied Biosciences, College of Agriculture and Life Science, Kyungpook National University, Daegu, South Korea
| | - Adil Hussain
- Department of Entomology, Abdul Wali Khan University, Mardan, Pakistan
| | - Byung-Wook Yun
- Laboratory of Plant Molecular Pathology and Functional Genomics, Department of Plant Biosciences, School of Applied Biosciences, College of Agriculture and Life Science, Kyungpook National University, Daegu, South Korea
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14
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Ochieno DMW, Karoney EM, Muge EK, Nyaboga EN, Baraza DL, Shibairo SI, Naluyange V. Rhizobium-Linked Nutritional and Phytochemical Changes Under Multitrophic Functional Contexts in Sustainable Food Systems. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2021. [DOI: 10.3389/fsufs.2020.604396] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Rhizobia are bacteria that exhibit both endophytic and free-living lifestyles. Endophytic rhizobial strains are widely known to infect leguminous host plants, while some do infect non-legumes. Infection of leguminous roots often results in the formation of root nodules. Associations between rhizobia and host plants may result in beneficial or non-beneficial effects. Such effects are linked to various biochemical changes that have far-reaching implications on relationships between host plants and the dependent multitrophic biodiversity. This paper explores relationships that exist between rhizobia and various plant species. Emphasis is on nutritional and phytochemical changes that occur in rhizobial host plants, and how such changes affect diverse consumers at different trophic levels. The purpose of this paper is to bring into context various aspects of such interactions that could improve knowledge on the application of rhizobia in different fields. The relevance of rhizobia in sustainable food systems is addressed in context.
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15
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Toniutti MA, Albicoro FJ, Castellani LG, López García SL, Fornasero LV, Zuber NE, Vera LM, Vacca C, Cafiero JH, Winkler A, Kalinowski J, Lagares A, Torres Tejerizo GA, Del Papa MF. Genome sequence of Bradyrhizobium yuanmingense strain P10 130, a highly efficient nitrogen-fixing bacterium that could be used for Desmodium incanum inoculation. Gene 2020; 768:145267. [PMID: 33122079 DOI: 10.1016/j.gene.2020.145267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 08/08/2020] [Accepted: 10/20/2020] [Indexed: 10/23/2022]
Abstract
Strain P10 130, an isolated Bradyrhizobium strain from Argentina which promotes the growth of the leguminous plant Desmodium incanum by different mechanisms was previously selected as the best candidate for D. incanum inoculation based on broader selective criteria. A close relationship between this strain and B. yuanmingense was determined by MALDI BioTyper identification and 16S rRNA gene phylogenetic analysis. This study aimed to analyse the genome sequence of B. yuanmingense P10 130 in order to deepen our knowledge regarding its plant growth-promoting traits and to establish its phylogenetic relationship with other species of Bradyrhizobium genus. The genome size of strain P10 130 was estimated to be 7.54 Mb that consisted of 65 contigs. Genome Average Nucleotide Identity (ANI) analysis revealed that B. yuanmingense CCBAU 10071 T was the closest strain to P10 130 with ca. 96% identity. Further analysis of the genome of B. yuanmingense P10 130 identified 20 nod/nol/NOE, 14 nif/18 fix, 5 nap/5 nor genes, which may be potentially involved in nodulation, nitrogen fixation, and denitrification process respectively. Genome sequence of B. yuanmingense P10 130 is a valuable source of information to continue the research of its potential industrial production as a biofertilizer of D. incanum.
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Affiliation(s)
| | - Francisco Javier Albicoro
- IBBM - Instituto de Biotecnología y Biología Molecular, CONICET - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calles 47 y 115 (1900) La Plata, Argentina
| | - Lucas Gabriel Castellani
- IBBM - Instituto de Biotecnología y Biología Molecular, CONICET - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calles 47 y 115 (1900) La Plata, Argentina
| | - Silvina Laura López García
- IBBM - Instituto de Biotecnología y Biología Molecular, CONICET - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calles 47 y 115 (1900) La Plata, Argentina
| | | | - Nicolás Emilio Zuber
- IBBM - Instituto de Biotecnología y Biología Molecular, CONICET - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calles 47 y 115 (1900) La Plata, Argentina
| | - Leda Mailén Vera
- IBBM - Instituto de Biotecnología y Biología Molecular, CONICET - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calles 47 y 115 (1900) La Plata, Argentina
| | - Carolina Vacca
- IBBM - Instituto de Biotecnología y Biología Molecular, CONICET - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calles 47 y 115 (1900) La Plata, Argentina
| | - Juan Hilario Cafiero
- IBBM - Instituto de Biotecnología y Biología Molecular, CONICET - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calles 47 y 115 (1900) La Plata, Argentina
| | - Anika Winkler
- CeBiTec - Centrum für Biotechnologie, Universität Bielefeld, Bielefeld, Germany
| | - Jörn Kalinowski
- CeBiTec - Centrum für Biotechnologie, Universität Bielefeld, Bielefeld, Germany
| | - Antonio Lagares
- IBBM - Instituto de Biotecnología y Biología Molecular, CONICET - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calles 47 y 115 (1900) La Plata, Argentina
| | - Gonzalo Arturo Torres Tejerizo
- IBBM - Instituto de Biotecnología y Biología Molecular, CONICET - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calles 47 y 115 (1900) La Plata, Argentina.
| | - María Florencia Del Papa
- IBBM - Instituto de Biotecnología y Biología Molecular, CONICET - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calles 47 y 115 (1900) La Plata, Argentina.
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16
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Compant S, Cambon MC, Vacher C, Mitter B, Samad A, Sessitsch A. The plant endosphere world - bacterial life within plants. Environ Microbiol 2020; 23:1812-1829. [PMID: 32955144 DOI: 10.1111/1462-2920.15240] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 09/11/2020] [Accepted: 09/16/2020] [Indexed: 12/23/2022]
Abstract
The plant endosphere is colonized by complex microbial communities and microorganisms, which colonize the plant interior at least part of their lifetime and are termed endophytes. Their functions range from mutualism to pathogenicity. All plant organs and tissues are generally colonized by bacterial endophytes and their diversity and composition depend on the plant, the plant organ and its physiological conditions, the plant growth stage as well as on the environment. Plant-associated microorganisms, and in particular endophytes, have lately received high attention, because of the increasing awareness of the importance of host-associated microbiota for the functioning and performance of their host. Some endophyte functions are known from mostly lab assays, genome prediction and few metagenome analyses; however, we have limited understanding on in planta activities, particularly considering the diversity of micro-environments and the dynamics of conditions. In our review, we present recent findings on endosphere environments, their physiological conditions and endophyte colonization. Furthermore, we discuss microbial functions, the interaction between endophytes and plants as well as methodological limitations of endophyte research. We also provide an outlook on needs of future research to improve our understanding on the role of microbiota colonizing the endosphere on plant traits and ecosystem functioning.
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Affiliation(s)
- Stéphane Compant
- Center for Health and Bioresources, Bioresources Unit, Konrad Lorenz Straße 24, AIT Austrian Institute of Technology, Tulln, A-3430, Austria
| | | | | | - Birgit Mitter
- Center for Health and Bioresources, Bioresources Unit, Konrad Lorenz Straße 24, AIT Austrian Institute of Technology, Tulln, A-3430, Austria
| | - Abdul Samad
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Québec, G1V4C7, Canada
| | - Angela Sessitsch
- Center for Health and Bioresources, Bioresources Unit, Konrad Lorenz Straße 24, AIT Austrian Institute of Technology, Tulln, A-3430, Austria
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17
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OnfD, an AraC-Type Transcriptional Regulator Encoded by Rhizobium tropici CIAT 899 and Involved in Nod Factor Synthesis and Symbiosis. Appl Environ Microbiol 2020; 86:AEM.01297-20. [PMID: 32709725 PMCID: PMC7499043 DOI: 10.1128/aem.01297-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 07/16/2020] [Indexed: 02/06/2023] Open
Abstract
Rhizobium tropici CIAT 899 is a broad-host-range rhizobial strain that establishes symbiotic interactions with legumes and tolerates different environmental stresses such as heat, acidity, or salinity. This rhizobial strain produces a wide variety of symbiotically active nodulation factors (NF) induced not only by the presence of plant-released flavonoids but also under osmotic stress conditions through the LysR-type transcriptional regulators NodD1 (flavonoids) and NodD2 (osmotic stress). However, the activation of NodD2 under high-osmotic-stress conditions remains elusive. Here, we have studied the role of a new AraC-type regulator (named as OnfD) in the symbiotic interaction of R. tropici CIAT 899 with Phaseolus vulgaris and Lotus plants. We determined that OnfD is required under salt stress conditions for the transcriptional activation of the nodulation genes and therefore the synthesis and export of NF, which are required for a successful symbiosis with P. vulgaris Moreover, using bacterial two-hybrid analysis, we demonstrated that the OnfD and NodD2 proteins form homodimers and OnfD/NodD2 form heterodimers, which could be involved in the production of NF in the presence of osmotic stress conditions since both regulators are required for NF synthesis in the presence of salt. A structural model of OnfD is presented and discussed.IMPORTANCE The synthesis and export of rhizobial NF are mediated by a conserved group of LysR-type regulators, the NodD proteins. Here, we have demonstrated that a non-LysR-type regulator, an AraC-type protein, is required for the transcriptional activation of symbiotic genes and for the synthesis of symbiotically active NF under salt stress conditions.
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18
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Abstract
By analyzing successive lifestyle stages of a model Rhizobium-legume symbiosis using mariner-based transposon insertion sequencing (INSeq), we have defined the genes required for rhizosphere growth, root colonization, bacterial infection, N2-fixing bacteroids, and release from legume (pea) nodules. While only 27 genes are annotated as nif and fix in Rhizobium leguminosarum, we show 603 genetic regions (593 genes, 5 transfer RNAs, and 5 RNA features) are required for the competitive ability to nodulate pea and fix N2 Of these, 146 are common to rhizosphere growth through to bacteroids. This large number of genes, defined as rhizosphere-progressive, highlights how critical successful competition in the rhizosphere is to subsequent infection and nodulation. As expected, there is also a large group (211) specific for nodule bacteria and bacteroid function. Nodule infection and bacteroid formation require genes for motility, cell envelope restructuring, nodulation signaling, N2 fixation, and metabolic adaptation. Metabolic adaptation includes urea, erythritol and aldehyde metabolism, glycogen synthesis, dicarboxylate metabolism, and glutamine synthesis (GlnII). There are 17 separate lifestyle adaptations specific to rhizosphere growth and 23 to root colonization, distinct from infection and nodule formation. These results dramatically highlight the importance of competition at multiple stages of a Rhizobium-legume symbiosis.
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19
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Liu J, Yu X, Qin Q, Dinkins RD, Zhu H. The Impacts of Domestication and Breeding on Nitrogen Fixation Symbiosis in Legumes. Front Genet 2020; 11:00973. [PMID: 33014021 PMCID: PMC7461779 DOI: 10.3389/fgene.2020.00973] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 07/31/2020] [Indexed: 01/12/2023] Open
Abstract
Legumes are the second most important family of crop plants. One defining feature of legumes is their unique ability to establish a nitrogen-fixing root nodule symbiosis with soil bacteria known as rhizobia. Since domestication from their wild relatives, crop legumes have been under intensive breeding to improve yield and other agronomic traits but with little attention paid to the belowground symbiosis traits. Theoretical models predict that domestication and breeding processes, coupled with high−input agricultural practices, might have reduced the capacity of crop legumes to achieve their full potential of nitrogen fixation symbiosis. Testing this prediction requires characterizing symbiosis traits in wild and breeding populations under both natural and cultivated environments using genetic, genomic, and ecological approaches. However, very few experimental studies have been dedicated to this area of research. Here, we review how legumes regulate their interactions with soil rhizobia and how domestication, breeding and agricultural practices might have affected nodulation capacity, nitrogen fixation efficiency, and the composition and function of rhizobial community. We also provide a perspective on how to improve legume-rhizobial symbiosis in sustainable agricultural systems.
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Affiliation(s)
- Jinge Liu
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, United States
| | - Xiaocheng Yu
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, United States
| | - Qiulin Qin
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, United States
| | - Randy D Dinkins
- Forage-Animal Production Research Unit, United States Department of Agriculture-Agricultural Research Service, Lexington, KY, United States
| | - Hongyan Zhu
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, United States
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20
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Zhang C, Qi M, Zhang X, Wang Q, Yu Y, Zhang Y, Kong Z. Rhizobial infection triggers systemic transport of endogenous RNAs between shoots and roots in soybean. SCIENCE CHINA. LIFE SCIENCES 2020; 63:1213-1226. [PMID: 32221813 DOI: 10.1007/s11427-019-1608-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Accepted: 12/16/2019] [Indexed: 10/24/2022]
Abstract
Legumes have evolved a symbiotic relationship with rhizobial bacteria and their roots form unique nitrogen-fixing organs called nodules. Studies have shown that abiotic and biotic stresses alter the profile of gene expression and transcript mobility in plants. However, little is known about the systemic transport of RNA between roots and shoots in response to rhizobial infection on a genome-wide scale during the formation of legume-rhizobia symbiosis. In our study, we found that two soybean (Glycine max) cultivars, Peking and Williams, show a high frequency of single nucleotide polymorphisms; this allowed us to characterize the origin and mobility of transcripts in hetero-grafts of these two cultivars. We identified 4,552 genes that produce mobile RNAs in soybean, and found that rhizobial infection triggers mass transport of mRNAs between shoots and roots at the early stage of nodulation. The majority of these mRNAs are of relatively low abundance and their transport occurs in a selective manner in soybean plants. Notably, the mRNAs that moved from shoots to roots at the early stage of nodulation were enriched in many nodule-related responsive processes. Moreover, the transcripts of many known symbiosis-related genes that are induced by rhizobial infection can move between shoots and roots. Our findings provide a deeper understanding of endogenous RNA transport in legume-rhizobia symbiotic processes.
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Affiliation(s)
- Chen Zhang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Meifang Qi
- Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaxia Zhang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Qi Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yanjun Yu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yijing Zhang
- Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China.
| | - Zhaosheng Kong
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China.
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21
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Signorelli S, Sainz M, Tabares-da Rosa S, Monza J. The Role of Nitric Oxide in Nitrogen Fixation by Legumes. FRONTIERS IN PLANT SCIENCE 2020; 11:521. [PMID: 32582223 PMCID: PMC7286274 DOI: 10.3389/fpls.2020.00521] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 04/06/2020] [Indexed: 05/26/2023]
Abstract
The legume-rhizobia symbiosis is an important process in agriculture because it allows the biological nitrogen fixation (BNF) which contributes to increasing the levels of nitrogen in the soil. Nitric oxide (⋅NO) is a small free radical molecule having diverse signaling roles in plants. Here we present and discuss evidence showing the role of ⋅NO during different stages of the legume-rhizobia interaction such as recognition, infection, nodule development, and nodule senescence. Although the mechanisms by which ⋅NO modulates this interaction are not fully understood, we discuss potential mechanisms including its interaction with cytokinin, auxin, and abscisic acid signaling pathways. In matures nodules, a more active metabolism of ⋅NO has been reported and both the plant and rhizobia participate in ⋅NO production and scavenging. Although ⋅NO has been shown to induce the expression of genes coding for NITROGENASE, controlling the levels of ⋅NO in mature nodules seems to be crucial as ⋅NO was shown to be a potent inhibitor of NITROGENASE activity, to induce nodule senescence, and reduce nitrogen assimilation. In this sense, LEGHEMOGLOBINS (Lbs) were shown to play an important role in the scavenging of ⋅NO and reactive nitrogen species (RNS), potentially more relevant in senescent nodules. Even though ⋅NO can reduce NITROGENASE activity, most reports have linked ⋅NO to positive effects on BNF. This can relate mainly to the regulation of the spatiotemporal distribution of ⋅NO which favors some effects over others. Another plausible explanation for this observation is that the negative effect of ⋅NO requires its direct interaction with NITROGENASE, whereas the positive effect of ⋅NO is related to its signaling function, which results in an amplifier effect. In the near future, it would be interesting to explore the role of environmental stress-induced ⋅NO in BNF.
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Affiliation(s)
- Santiago Signorelli
- Laboratorio de Bioquímica, Departamento de Biología Vegetal, Facultad de Agronomía, Universidad de la República, Montevideo, Uruguay
- The School of Molecular Sciences, Faculty of Science, The University of Western Australia, Crawley, WA, Australia
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, WA, Australia
| | - Martha Sainz
- Laboratorio de Bioquímica, Departamento de Biología Vegetal, Facultad de Agronomía, Universidad de la República, Montevideo, Uruguay
| | - Sofía Tabares-da Rosa
- Laboratorio de Bioquímica, Departamento de Biología Vegetal, Facultad de Agronomía, Universidad de la República, Montevideo, Uruguay
| | - Jorge Monza
- Laboratorio de Bioquímica, Departamento de Biología Vegetal, Facultad de Agronomía, Universidad de la República, Montevideo, Uruguay
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22
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Tong W, Li X, Wang E, Cao Y, Chen W, Tao S, Wei G. Genomic insight into the origins and evolution of symbiosis genes in Phaseolus vulgaris microsymbionts. BMC Genomics 2020; 21:186. [PMID: 32106817 PMCID: PMC7047383 DOI: 10.1186/s12864-020-6578-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 02/13/2020] [Indexed: 01/02/2023] Open
Abstract
Background Phaseolus vulgaris (common bean) microsymbionts belonging to the bacterial genera Rhizobium, Bradyrhizobium, and Ensifer (Sinorhizobium) have been isolated across the globe. Individual symbiosis genes (e.g., nodC) of these rhizobia can be different within each genus and among distinct genera. Little information is available about the symbiotic structure of indigenous Rhizobium strains nodulating introduced bean plants or the emergence of a symbiotic ability to associate with bean plants in Bradyrhizobium and Ensifer strains. Here, we sequenced the genomes of 29 representative bean microsymbionts (21 Rhizobium, four Ensifer, and four Bradyrhizobium) and compared them with closely related reference strains to estimate the origins of symbiosis genes among these Chinese bean microsymbionts. Results Comparative genomics demonstrated horizontal gene transfer exclusively at the plasmid level, leading to expanded diversity of bean-nodulating Rhizobium strains. Analysis of vertically transferred genes uncovered 191 (out of the 2654) single-copy core genes with phylogenies strictly consistent with the taxonomic status of bacterial species, but none were found on symbiosis plasmids. A common symbiotic region was wholly conserved within the Rhizobium genus yet different from those of the other two genera. A single strain of Ensifer and two Bradyrhizobium strains shared similar gene content with soybean microsymbionts in both chromosomes and symbiotic regions. Conclusions The 19 native bean Rhizobium microsymbionts were assigned to four defined species and six putative novel species. The symbiosis genes of R. phaseoli, R. sophoriradicis, and R. esperanzae strains that originated from Mexican bean-nodulating strains were possibly introduced alongside bean seeds. R. anhuiense strains displayed distinct host ranges, indicating transition into bean microsymbionts. Among the six putative novel species exclusive to China, horizontal transfer of symbiosis genes suggested symbiosis with other indigenous legumes and loss of originally symbiotic regions or non-symbionts before the introduction of common bean into China. Genome data for Ensifer and Bradyrhizobium strains indicated symbiotic compatibility between microsymbionts of common bean and other hosts such as soybean.
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Affiliation(s)
- Wenjun Tong
- 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, Yangling, Shaanxi, 712100, People's Republic of China
| | - Xiangchen Li
- 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, Yangling, Shaanxi, 712100, People's Republic of China.,Bioinformatics Center, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Entao Wang
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, 11340, México D.F, Mexico
| | - Ying Cao
- 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, 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, Yangling, Shaanxi, 712100, People's Republic of China.
| | - Shiheng Tao
- Bioinformatics Center, Northwest A&F University, 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, Yangling, Shaanxi, 712100, People's Republic of China.
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23
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Modulation of Quorum Sensing as an Adaptation to Nodule Cell Infection during Experimental Evolution of Legume Symbionts. mBio 2020; 11:mBio.03129-19. [PMID: 31992622 PMCID: PMC6989110 DOI: 10.1128/mbio.03129-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Over millions of years, changes have occurred in regulatory circuitries in response to genome reorganization and/or persistent changes in environmental conditions. How bacteria optimize regulatory circuitries is crucial to understand bacterial adaptation. Here, we analyzed the experimental evolution of the plant pathogen Ralstonia solanacearum into legume symbionts after the transfer of a natural plasmid encoding the essential mutualistic genes. We showed that the Phc quorum sensing system required for the virulence of the ancestral bacterium was reconfigured to improve intracellular infection of root nodules induced by evolved Ralstonia A single mutation in either the PhcB autoinducer synthase or the PhcQ regulator of the sensory cascade tuned the kinetics of activation of the central regulator PhcA in response to cell density so that the minimal stimulatory concentration of autoinducers needed for a given response was increased. Yet, a change in the expression of a PhcA target gene was observed in infection threads progressing in root hairs, suggesting early programming for the late accommodation of bacteria in nodule cells. Moreover, this delayed switch to the quorum sensing mode decreased the pathogenicity of the ancestral strain, illustrating the functional plasticity of regulatory systems and showing how a small modulation in signal response can produce drastic changes in bacterial lifestyle.IMPORTANCE Rhizobia are soil bacteria from unrelated genera able to form a mutualistic relationship with legumes. Bacteria induce the formation of root nodules, invade nodule cells, and fix nitrogen to the benefit of the plant. Rhizobial lineages emerged from the horizontal transfer of essential symbiotic genes followed by genome remodeling to activate and/or optimize the acquired symbiotic potential. This evolutionary scenario was replayed in a laboratory evolution experiment in which the plant pathogen Ralstonia solanacearum successively evolved the capacities to nodulate Mimosa pudica and poorly invade, then massively invade, nodule cells. In some lines, the improvement of intracellular infection was achieved by mutations modulating a quorum sensing regulatory system of the ancestral strain. This modulation that affects the activity of a central regulator during the earliest stages of symbiosis has a huge impact on late stages of symbiosis. This work showed that regulatory rewiring is the main driver of this pathogeny-symbiosis transition.
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24
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Sulima AS, Zhukov VA, Kulaeva OA, Vasileva EN, Borisov AY, Tikhonovich IA. New sources of Sym2A allele in the pea ( Pisum sativum L.) carry the unique variant of candidate LysM-RLK gene LykX. PeerJ 2019; 7:e8070. [PMID: 31768303 PMCID: PMC6874852 DOI: 10.7717/peerj.8070] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 10/20/2019] [Indexed: 01/09/2023] Open
Abstract
At the onset of legume-rhizobial symbiosis, the mutual recognition of partners occurs based on a complicated interaction between signal molecules and receptors. Bacterial signal molecules named Nod factors ("nodulation factors") are perceived by the plant LysM-containing receptor-like kinases (LysM-RLKs) that recognize details of its structure (i.e., unique substitutions), thus providing the conditions particular to symbiosis. In the garden pea (Pisum sativum L.), the allelic state of Sym2 gene has long been reported to regulate the symbiotic specificity: for infection to be successful, plants with the Sym2 A allele (for "Sym2 Afghan", as these genotypes originate mostly from Afghanistan) require an additional acetylation of the Nod factor which is irrelevant for genotypes with the Sym2 E allele (for "Sym2 European"). Despite being described about 90 years ago, Sym2 has not yet been cloned, though phenotypic analysis suggests it probably encodes a receptor for the Nod factor. Recently, we described a novel pea gene LykX (PsLykX) from the LysM-RLK gene family that demonstrates a perfect correlation between its allelic state and the symbiotic specificity of the Sym2 A-type. Here we report on a series of Middle-Eastern pea genotypes exhibiting the phenotype of narrow symbiotic specificity discovered in the VIR plant genetic resources gene bank (Saint-Petersburg, Russia). These genotypes are new sources of Sym2 A, as has been confirmed by an allelism test with Sym2 A pea cv. Afghanistan. Within these genotypes, LykX is present either in the allelic state characteristic for cv. Afghanistan, or in another, minor allelic state found in two genotypes from Tajikistan and Turkmenistan. Plants carrying the second allele demonstrate the same block of rhizobial infection as cv. Afghanistan when inoculated with an incompatible strain. Intriguingly, this "Tajik" allele of LykX differs from the "European" one by a single nucleotide polymorphism leading to an R75P change in the receptor part of the putative protein. Thus, our new data are in agreement with the hypothesis concerning the identity of LykX and the elusive Sym2 gene.
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Affiliation(s)
- Anton S Sulima
- All-Russia Research Institute for Agricultural Microbiology, Saint-Petersburg, Russia
| | - Vladimir A Zhukov
- All-Russia Research Institute for Agricultural Microbiology, Saint-Petersburg, Russia
| | - Olga A Kulaeva
- All-Russia Research Institute for Agricultural Microbiology, Saint-Petersburg, Russia
| | - Ekaterina N Vasileva
- All-Russia Research Institute for Agricultural Microbiology, Saint-Petersburg, Russia
| | - Alexey Y Borisov
- All-Russia Research Institute for Agricultural Microbiology, Saint-Petersburg, Russia
| | - Igor A Tikhonovich
- All-Russia Research Institute for Agricultural Microbiology, Saint-Petersburg, Russia.,Faculty of Biology, St. Petersburg State University, Saint-Petersburg, Russia
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25
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Farci D, Sanna C, Medda R, Pintus F, Kalaji HM, Kirkpatrick J, Piano D. Shedding light on the presymbiontic phase of C. arietinum. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 143:224-231. [PMID: 31521050 DOI: 10.1016/j.plaphy.2019.09.014] [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: 07/16/2019] [Revised: 09/08/2019] [Accepted: 09/08/2019] [Indexed: 06/10/2023]
Abstract
A complex network of symbiotic events between plants and bacteria allows the biosphere to exploit the atmospheric reservoir of molecular nitrogen. In seeds, a series of presymbiotic steps are already identified during imbibition, while interactions between the host and its symbiont begin in the early stages of germination. In the present study, a detailed analysis of the substances' complex delivered by Cicer arietinum seeds during imbibition showed a relevant presence of proteins and amino acids, which, except for cysteine, occurred with the whole proteinogenic pool. The imbibing solution was found to provide essential probiotic properties able to sustain the growth of the specific chickpea symbiont Mesorhizobium ciceri. Moreover, the imbibing solution, behaving as a complete medium, was found to be critically important for the symbiont's attraction, a fact this that is strictly related to the presence of the amino acids glycine, serine, and threonine. Here, the presence of these amino acids is constantly supported by the presence of the enzymes serine hydroxymethyltransferase and formyltetrahydrofolate deformylase, which are both involved in their biosynthesis. The reported findings are discussed in the light of the pivotal role played by the imbibing solution in attracting and sustaining symbiosis between the host and its symbiont.
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Affiliation(s)
- Domenica Farci
- Laboratory of Plant Physiology and Photobiology, Department of Life and Environmental Sciences, University of Cagliari, V.le S. Ignazio da Laconi 13, 09123, Cagliari, Italy; White Hill Company, Ciołkowskiego 161, 15-545, Białystok, Poland; Department of Plant Physiology, Warsaw University of Life Sciences - SGGW, Nowoursynowska Str. 159, 02776, Warsaw, Poland
| | - Cinzia Sanna
- Laboratory of Pharmaceutical Botany, Department of Life and Environmental Sciences, University of Cagliari, V.le S. Ignazio da Laconi 13, 09123, Cagliari, Italy
| | - Rosaria Medda
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria, 09042, Monserrato, Italy
| | - Francesca Pintus
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria, 09042, Monserrato, Italy
| | - Hazem M Kalaji
- White Hill Company, Ciołkowskiego 161, 15-545, Białystok, Poland; Department of Plant Physiology, Warsaw University of Life Sciences - SGGW, Nowoursynowska Str. 159, 02776, Warsaw, Poland
| | - Joanna Kirkpatrick
- Leibniz Institute on Aging - Fritz Lipmann Institute, Beutenbergstraβe 11, 07745, Jena, Germany
| | - Dario Piano
- Laboratory of Plant Physiology and Photobiology, Department of Life and Environmental Sciences, University of Cagliari, V.le S. Ignazio da Laconi 13, 09123, Cagliari, Italy; Department of Plant Physiology, Warsaw University of Life Sciences - SGGW, Nowoursynowska Str. 159, 02776, Warsaw, Poland.
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Mayer E, Dörr de Quadros P, Fulthorpe R. Plantibacter flavus, Curtobacterium herbarum, Paenibacillus taichungensis, and Rhizobium selenitireducens Endophytes Provide Host-Specific Growth Promotion of Arabidopsis thaliana, Basil, Lettuce, and Bok Choy Plants. Appl Environ Microbiol 2019; 85:e00383-19. [PMID: 31350315 PMCID: PMC6752021 DOI: 10.1128/aem.00383-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Accepted: 07/06/2019] [Indexed: 11/20/2022] Open
Abstract
A collection of bacterial endophytes isolated from stem tissues of plants growing in soils highly contaminated with petroleum hydrocarbons were screened for plant growth-promoting capabilities. Twenty-seven endophytic isolates significantly improved the growth of Arabidopsis thaliana plants in comparison to that of uninoculated control plants. The five most beneficial isolates, one strain each of Curtobacterium herbarum, Paenibacillus taichungensis, and Rhizobium selenitireducens and two strains of Plantibacter flavus were further examined for growth promotion in Arabidopsis, lettuce, basil, and bok choy plants. Host-specific plant growth promotion was observed when plants were inoculated with the five bacterial strains. P. flavus strain M251 increased the total biomass and total root length of Arabidopsis plants by 4.7 and 5.8 times, respectively, over that of control plants and improved lettuce and basil root growth, while P. flavus strain M259 promoted Arabidopsis shoot and root growth, lettuce and basil root growth, and bok choy shoot growth. A genome comparison between P. flavus strains M251 and M259 showed that both genomes contain up to 70 actinobacterial putative plant-associated genes and genes involved in known plant-beneficial pathways, such as those for auxin and cytokinin biosynthesis and 1-aminocyclopropane-1-carboxylate deaminase production. This study provides evidence of direct plant growth promotion by Plantibacter flavusIMPORTANCE The discovery of new plant growth-promoting bacteria is necessary for the continued development of biofertilizers, which are environmentally friendly and cost-efficient alternatives to conventional chemical fertilizers. Biofertilizer effects on plant growth can be inconsistent due to the complexity of plant-microbe interactions, as the same bacteria can be beneficial to the growth of some plant species and neutral or detrimental to others. We examined a set of bacterial endophytes isolated from plants growing in a unique petroleum-contaminated environment to discover plant growth-promoting bacteria. We show that strains of Plantibacter flavus exhibit strain-specific plant growth-promoting effects on four different plant species.
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Affiliation(s)
- Evan Mayer
- University of Toronto Scarborough, Toronto, Ontario, Canada
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Smigielski L, Laubach EM, Pesch L, Glock JML, Albrecht F, Slusarenko A, Panstruga R, Kuhn H. Nodulation Induces Systemic Resistance of Medicago truncatula and Pisum sativum Against Erysiphe pisi and Primes for Powdery Mildew-Triggered Salicylic Acid Accumulation. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:1243-1255. [PMID: 31025899 DOI: 10.1094/mpmi-11-18-0304-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Plants encounter beneficial and detrimental microorganisms both above- and belowground and the health status of the plant depends on the composition of this pan-microbiome. Beneficial microorganisms contribute to plant nutrition or systemically or locally protect plants against pathogens, thus facilitating adaptation to a variety of environments. Induced systemic resistance, caused by root-associated microbes, manifests as aboveground resistance against necrotrophic pathogens and is mediated by jasmonic acid/ethylene-dependent signaling. By contrast, systemic acquired resistance relies on salicylic acid (SA) signaling and confers resistance against secondary infection by (hemi)biotrophic pathogens. To investigate whether symbiotic rhizobia that are ubiquitously found in natural ecosystems are able to modulate resistance against biotrophs, we tested the impact of preestablished nodulation of Medicago truncatula and pea (Pisum sativum) plants against infection by the powdery mildew fungus Erysiphe pisi. We found that root symbiosis interfered with fungal penetration of M. truncatula and reduced asexual spore formation on pea leaves independently of symbiotic nitrogen fixation. Improved resistance of nodulated plants correlated with elevated levels of free SA and SA-dependent marker gene expression upon powdery mildew infection. Our results suggest that nodulation primes the plants systemically for E. pisi-triggered SA accumulation and defense gene expression, resulting in increased resistance.
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Affiliation(s)
- Lara Smigielski
- Institute for Biology I, Unit of Plant Molecular Cell Biology, RWTH Aachen University, Worringerweg 1, 52056 Aachen, Germany
| | - Eva-Maria Laubach
- Institute for Biology I, Unit of Plant Molecular Cell Biology, RWTH Aachen University, Worringerweg 1, 52056 Aachen, Germany
| | - Lina Pesch
- Institute for Biology I, Unit of Plant Molecular Cell Biology, RWTH Aachen University, Worringerweg 1, 52056 Aachen, Germany
| | - Joanna Marie Leyva Glock
- Institute for Biology I, Unit of Plant Molecular Cell Biology, RWTH Aachen University, Worringerweg 1, 52056 Aachen, Germany
| | - Frank Albrecht
- Institute for Biology III, Department of Plant Physiology, RWTH Aachen University
| | - Alan Slusarenko
- Institute for Biology III, Department of Plant Physiology, RWTH Aachen University
| | - Ralph Panstruga
- Institute for Biology I, Unit of Plant Molecular Cell Biology, RWTH Aachen University, Worringerweg 1, 52056 Aachen, Germany
| | - Hannah Kuhn
- Institute for Biology I, Unit of Plant Molecular Cell Biology, RWTH Aachen University, Worringerweg 1, 52056 Aachen, Germany
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28
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Pislariu CI, Sinharoy S, Torres-Jerez I, Nakashima J, Blancaflor EB, Udvardi MK. The Nodule-Specific PLAT Domain Protein NPD1 Is Required for Nitrogen-Fixing Symbiosis. PLANT PHYSIOLOGY 2019; 180:1480-1497. [PMID: 31061106 PMCID: PMC6752919 DOI: 10.1104/pp.18.01613] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 04/22/2019] [Indexed: 05/06/2023]
Abstract
Symbiotic nitrogen fixation by rhizobia in legume root nodules is a key source of nitrogen for sustainable agriculture. Genetic approaches have revealed important roles for only a few of the thousands of plant genes expressed during nodule development and symbiotic nitrogen fixation. Previously, we isolated >100 nodulation and nitrogen fixation mutants from a population of Tnt1-insertion mutants of Medigaco truncatula Using Tnt1 as a tag to identify genetic lesions in these mutants, we discovered that insertions in a M. truncatula nodule-specific polycystin-1, lipoxygenase, α-toxin (PLAT) domain-encoding gene, MtNPD1, resulted in development of ineffective nodules. Early stages of nodule development and colonization by the nitrogen-fixing bacterium Sinorhizobium meliloti appeared to be normal in the npd1 mutant. However, npd1 nodules ceased to grow after a few days, resulting in abnormally small, ineffective nodules. Rhizobia that colonized developing npd1 nodules did not differentiate completely into nitrogen-fixing bacteroids and quickly degraded. MtNPD1 expression was low in roots but increased significantly in developing nodules 4 d postinoculation, and expression accompanied invading rhizobia in the nodule infection zone and into the distal nitrogen fixation zone. A functional MtNPD1:GFP fusion protein localized in the space surrounding symbiosomes in infected cells. When ectopically expressed in tobacco (Nicotiana tabacum) leaves, MtNPD1 colocalized with vacuoles and the endoplasmic reticulum. MtNPD1 belongs to a cluster of five nodule-specific single PLAT domain-encoding genes, with apparent nonredundant functions.
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Affiliation(s)
- Catalina I Pislariu
- Plant Biology Division, Noble Research Institute, Ardmore, Oklahoma 73401
- Department of Biology, Texas Woman's University, Denton, Texas 76204
| | - Senjuti Sinharoy
- Plant Biology Division, Noble Research Institute, Ardmore, Oklahoma 73401
| | - Ivone Torres-Jerez
- Plant Biology Division, Noble Research Institute, Ardmore, Oklahoma 73401
| | - Jin Nakashima
- Plant Biology Division, Noble Research Institute, Ardmore, Oklahoma 73401
| | | | - Michael K Udvardi
- Plant Biology Division, Noble Research Institute, Ardmore, Oklahoma 73401
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Das DR, Horváth B, Kundu A, Kaló P, DasGupta M. Functional conservation of CYCLOPS in crack entry legume Arachis hypogaea. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 281:232-241. [PMID: 30824056 DOI: 10.1016/j.plantsci.2018.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 12/05/2018] [Accepted: 12/07/2018] [Indexed: 06/09/2023]
Abstract
Root nodule symbiosis in legumes is established following interaction of compatible rhizobia that activates an array of genes, commonly known as symbiotic-pathway, resulting in nodule development. In model legumes, bacterial entry mainly occurs through infection thread involving the expression of transcription factor CYCLOPS/IPD3. Here we show the functional analysis of AhCYCLOPS in Arachis hypogaea where bacteria invade roots through epidermal cracks. Exploiting significant cross-species domain conservation, trans-complementation experiments involving ectopic expression of AhCYCLOPS in transgenic hairy-roots of Medicago truncatula ipd3 mutants resulted in functional complementation of Medicago nodules. Moreover, native promoter of AhCYCLOPS was sufficient for this cross-species complementation irrespective of the different modes of infection of roots by rhizobia and nodule ontology. To unravel the role of AhCYCLOPS during 'crack-entry' nodulation in A. hypogaea, RNAi of AhCYCLOPS was performed which resulted in delayed nodule inception followed by drastic reduction in nodule number on transgenic hairy-roots. The infection zone of a significant number of RNAi nodules showed presence of infected cells with enlarged nucleus and rod shaped undifferentiated bacteria. Expression analysis showed downregulation of several nodulation responsible effectors endorsing the compromised condition of RNAi roots. Together, the results indicated that AhCYCLOPS plays an important role in A. hypogaea nodule development.
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Affiliation(s)
- Debapriya Rajlakshmi Das
- Department of Biochemistry, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, West Bengal, India
| | - Beatrix Horváth
- Agricultural Biotechnology Institute, NARIC, Szent-Györgyi Albert u. 4, Gödöllő, Hungary
| | - Anindya Kundu
- Department of Biochemistry, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, West Bengal, India
| | - Péter Kaló
- Agricultural Biotechnology Institute, NARIC, Szent-Györgyi Albert u. 4, Gödöllő, Hungary
| | - Maitrayee DasGupta
- Department of Biochemistry, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, West Bengal, India.
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Karmakar K, Kundu A, Rizvi AZ, Dubois E, Severac D, Czernic P, Cartieaux F, DasGupta M. Transcriptomic Analysis With the Progress of Symbiosis in 'Crack-Entry' Legume Arachis hypogaea Highlights Its Contrast With 'Infection Thread' Adapted Legumes. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:271-285. [PMID: 30109978 DOI: 10.1094/mpmi-06-18-0174-r] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In root-nodule symbiosis, rhizobial invasion and nodule organogenesis is host controlled. In most legumes, rhizobia enter through infection threads and nodule primordium in the cortex is induced from a distance. But in dalbergoid legumes like Arachis hypogaea, rhizobia directly invade cortical cells through epidermal cracks to generate the primordia. Herein, we report the transcriptional dynamics with the progress of symbiosis in A. hypogaea at 1 day postinfection (dpi) (invasion), 4 dpi (nodule primordia), 8 dpi (spread of infection in nodule-like structure), 12 dpi (immature nodules containing rod-shaped rhizobia), and 21 dpi (mature nodules with spherical symbiosomes). Expression of putative ortholog of symbiotic genes in 'crack entry' legume A. hypogaea was compared with infection thread-adapted model legumes. The contrasting features were i) higher expression of receptors like LYR3 and EPR3 as compared with canonical Nod factor receptors, ii) late induction of transcription factors like NIN and NSP2 and constitutive high expression of ERF1, EIN2, bHLH476, and iii) induction of divergent pathogenesis-responsive PR-1 genes. Additionally, symbiotic orthologs of SymCRK, ROP6, RR9, SEN1, and DNF2 were not detectable and microsynteny analysis indicated the absence of a RPG homolog in diploid parental genomes of A. hypogaea. The implications are discussed and a molecular framework that guides crack-entry symbiosis in A. hypogaea is proposed.
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Affiliation(s)
- Kanchan Karmakar
- 1 Department of Biochemistry, University of Calcutta, Kolkata 700019, India
| | - Anindya Kundu
- 1 Department of Biochemistry, University of Calcutta, Kolkata 700019, India
| | - Ahsan Z Rizvi
- 2 LSTM, Univ. Montpellier, CIRAD, INRA, IRD, SupAgro, Montpellier, France; and
| | - Emeric Dubois
- 3 Montpellier GenomiX (MGX), c/o Institut de Génomique Fonctionnelle, 141 rue de la cardonille, 34094 Montpellier Cedex 05, France
| | - Dany Severac
- 3 Montpellier GenomiX (MGX), c/o Institut de Génomique Fonctionnelle, 141 rue de la cardonille, 34094 Montpellier Cedex 05, France
| | - Pierre Czernic
- 2 LSTM, Univ. Montpellier, CIRAD, INRA, IRD, SupAgro, Montpellier, France; and
| | - Fabienne Cartieaux
- 2 LSTM, Univ. Montpellier, CIRAD, INRA, IRD, SupAgro, Montpellier, France; and
| | - Maitrayee DasGupta
- 1 Department of Biochemistry, University of Calcutta, Kolkata 700019, India
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31
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Piromyou P, Songwattana P, Teamtisong K, Tittabutr P, Boonkerd N, Tantasawat PA, Giraud E, Göttfert M, Teaumroong N. Mutualistic co-evolution of T3SSs during the establishment of symbiotic relationships between Vigna radiata and Bradyrhizobia. Microbiologyopen 2019; 8:e00781. [PMID: 30628192 PMCID: PMC6612562 DOI: 10.1002/mbo3.781] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 11/04/2018] [Accepted: 11/06/2018] [Indexed: 02/06/2023] Open
Abstract
This study supports the idea that the evolution of type III secretion system (T3SS) is one of the factors that controls Vigna radiata-bradyrhizobia symbiosis. Based on phylogenetic tree data and gene arrangements, it seems that the T3SSs of the Thai bradyrhizobial strains SUTN9-2, DOA1, and DOA9 and the Senegalese strain ORS3257 may share the same origin. Therefore, strains SUTN9-2, DOA1, DOA9, and ORS3257 may have evolved their T3SSs independently from other bradyrhizobia, depending on biological and/or geological events. For functional analyses, the rhcJ genes of ORS3257, SUTN9-2, DOA9, and USDA110 were disrupted. These mutations had cultivar-specific effects on nodulation properties. The T3SSs of ORS3257 and DOA9 showed negative effects on V. radiata nodulation, while the T3SS of SUTN9-2 showed no effect on V. radiata symbiosis. In the roots of V. radiata CN72, the expression levels of the PR1 gene after inoculation with ORS3257 and DOA9 were significantly higher than those after inoculation with ORS3257 ΩT3SS, DOA9 ΩT3SS, and SUTN9-2. The T3Es from ORS3257 and DOA9 could trigger PR1 expression, which ultimately leads to abort nodulation. In contrast, the T3E from SUTN9-2 reduced PR1 expression. It seems that the mutualistic relationship between SUTN9-2 and V. radiata may have led to the selection of the most well-adapted combination of T3SS and symbiotic bradyrhizobial genotype.
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Affiliation(s)
- Pongdet Piromyou
- School of Biotechnology, Institute of Agricultural TechnologySuranaree University of TechnologyNakhon RatchasimaThailand
| | - Pongpan Songwattana
- School of Biotechnology, Institute of Agricultural TechnologySuranaree University of TechnologyNakhon RatchasimaThailand
| | - Kamonluck Teamtisong
- The Center for Scientific and Technological EquipmentSuranaree University of TechnologyNakhon RatchasimaThailand
| | - Panlada Tittabutr
- School of Biotechnology, Institute of Agricultural TechnologySuranaree University of TechnologyNakhon RatchasimaThailand
| | - Nantakorn Boonkerd
- School of Biotechnology, Institute of Agricultural TechnologySuranaree University of TechnologyNakhon RatchasimaThailand
| | - Piyada Alisha Tantasawat
- School of Crop Production Technology, Institute of Agricultural TechnologySuranaree University of TechnologyNakhon RatchasimaThailand
| | - Eric Giraud
- IRD, Laboratory of Tropical and Mediterranean SymbiosesUMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de BaillarguetMontpellierFrance
| | | | - Neung Teaumroong
- School of Biotechnology, Institute of Agricultural TechnologySuranaree University of TechnologyNakhon RatchasimaThailand
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Dingjan T, Gillon É, Imberty A, Pérez S, Titz A, Ramsland PA, Yuriev E. Virtual Screening Against Carbohydrate-Binding Proteins: Evaluation and Application to Bacterial Burkholderia ambifaria Lectin. J Chem Inf Model 2018; 58:1976-1989. [DOI: 10.1021/acs.jcim.8b00185] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Tamir Dingjan
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Émilie Gillon
- University Grenoble Alpes, CNRS, CERMAV, 38000 Grenoble, France
| | - Anne Imberty
- University Grenoble Alpes, CNRS, CERMAV, 38000 Grenoble, France
| | - Serge Pérez
- University Grenoble Alpes, CNRS, DPM, 38000 Grenoble, France
| | - Alexander Titz
- Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research, D-66123 Saarbrücken, Germany
- Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany
- Department of Pharmacy, Saarland University, D-66123 Saarbrücken, Germany
| | - Paul A. Ramsland
- School of Science, RMIT University, Bundoora, Victoria 3083, Australia
- Department of Surgery Austin Health, University of Melbourne, Heidelberg, Victoria 3084, Australia
- Department of Immunology, Monash University, Alfred Medical Research and Education Precinct, Melbourne, Victoria 3004, Australia
- Burnet Institute, Melbourne, Victoria 3004, Australia
| | - Elizabeth Yuriev
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
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Roumiantseva ML, Saksaganskaia AS, Muntyan VS, Cherkasova ME, Simarov BV. Structural Polymorphism of Sinorhizobium meliloti Genes Related to Virulence and Salt Tolerance. RUSS J GENET+ 2018. [DOI: 10.1134/s1022795418050083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Ledermann R, Bartsch I, Müller B, Wülser J, Fischer HM. A Functional General Stress Response of Bradyrhizobium diazoefficiens Is Required for Early Stages of Host Plant Infection. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:537-547. [PMID: 29278144 DOI: 10.1094/mpmi-11-17-0284-r] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Phylogenetically diverse bacteria respond to various stress conditions by mounting a general stress response (GSR) resulting in the induction of protection or damage repair functions. In α-proteobacteria, the GSR is induced by a regulatory cascade consisting of the extracytoplasmic function (ECF) σ factor σEcfG, its anti-σ factor NepR, and the anti-anti-σ factor PhyR. We have reported previously that σEcfG and PhyR of Bradyrhizobium diazoefficiens (formerly named Bradyrhizobium japonicum), the nitrogen-fixing root nodule symbiont of soybean and related legumes, are required for efficient symbiosis; however, the precise role of the GSR remained undefined. Here, we analyze the symbiotic defects of a B. diazoefficiens mutant lacking σEcfG by comparing distinct infection stages of enzymatically or fluorescently tagged wild-type and mutant bacteria. Although root colonization and root hair curling were indistinguishable, the mutant was not competitive, and showed delayed development of emerging nodules and only a few infection threads. Consequently, many of the mutant-induced nodules were aborted, empty, or partially colonized. Congruent with these results, we found that σEcfG was active in bacteria present in root-hair-entrapped microcolonies and infection threads but not in root-associated bacteria and nitrogen-fixing bacteroids. We conclude that GSR-controlled functions are crucial for synchronization of infection thread formation, colonization, and nodule development.
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Affiliation(s)
- Raphael Ledermann
- ETH Zurich, Institute of Microbiology, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Ilka Bartsch
- ETH Zurich, Institute of Microbiology, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Barbara Müller
- ETH Zurich, Institute of Microbiology, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Janine Wülser
- ETH Zurich, Institute of Microbiology, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Hans-Martin Fischer
- ETH Zurich, Institute of Microbiology, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
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35
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Ramongolalaina C, Teraishi M, Okumoto Y. QTLs underlying the genetic interrelationship between efficient compatibility of Bradyrhizobium strains with soybean and genistein secretion by soybean roots. PLoS One 2018; 13:e0194671. [PMID: 29617389 PMCID: PMC5884529 DOI: 10.1371/journal.pone.0194671] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 03/07/2018] [Indexed: 12/18/2022] Open
Abstract
Soybean plants establish symbiotic relationships with soil rhizobia which form nodules on the plant roots. Nodule formation starts when the plant roots exudate isoflavonoids that induce nod gene expression of a specific Bradyrhizobium. We examined the specific indigenous rhizobia that form nodules with the soybean cultivars Peking and Tamahomare in different soils. PCR-RFLP analysis targeted to the 16S-23S rRNA gene internal transcribed spacer (ITS) region of the bacterial type of each root nodule showed that Bradyrhizobium japonicum (USDA110-type) and Bradyrhizobium elkanii (USDA94-type) had high compatibility with the Tamahomare and Peking cultivars, respectively. We grew 93 recombinant inbred lines (RIL) of soybean seeds derived from the cross between Peking and Tamahomare in three different field soils and identified the indigenous rhizobia nodulating each line using the same PCR-RFLP analysis. QTL analysis identified one QTL region in chromosome-18 with a highly significant additive effect that controls compatibility with both B. japonicum USDA110 and B. elkanii USDA94. We also measured the amount of daidzein and genistein secretion from roots of the 93 RILs by HPLC analysis. QTL analysis showed one QTL region in chromosome-18 controlling genistein secretion from roots and coinciding with that regulating compatibility of specific indigenous rhizobia with soybean. The amount of genistein may be a major regulatory factor in soybean-rhizobium compatibility.
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MESH Headings
- Bradyrhizobium/genetics
- Bradyrhizobium/physiology
- DNA, Bacterial/isolation & purification
- DNA, Bacterial/metabolism
- Flavonoids/metabolism
- Genistein/metabolism
- Isoflavones/metabolism
- Plant Roots/genetics
- Plant Roots/metabolism
- Plant Roots/microbiology
- Quantitative Trait Loci
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 16S/metabolism
- RNA, Ribosomal, 23S/genetics
- RNA, Ribosomal, 23S/metabolism
- Glycine max/genetics
- Glycine max/metabolism
- Glycine max/microbiology
- Symbiosis
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Affiliation(s)
| | - Masayoshi Teraishi
- Graduate School of Agriculture, Kyoto University, Oiwake, Kitashirakawa, Sakyo, Kyoto, Japan
| | - Yutaka Okumoto
- Graduate School of Agriculture, Kyoto University, Oiwake, Kitashirakawa, Sakyo, Kyoto, Japan
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36
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Chromium(VI) Toxicity in Legume Plants: Modulation Effects of Rhizobial Symbiosis. BIOMED RESEARCH INTERNATIONAL 2018; 2018:8031213. [PMID: 29662899 PMCID: PMC5832134 DOI: 10.1155/2018/8031213] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 12/31/2017] [Indexed: 11/18/2022]
Abstract
Most legume species have the ability to establish a symbiotic relationship with soil nitrogen-fixing rhizobacteria that promote plant growth and productivity. There is an increasing evidence of reactive oxygen species (ROS) important role in formation of legume-rhizobium symbiosis and nodule functioning. Environmental pollutants such as chromium compounds can cause damage to rhizobia, legumes, and their symbiosis. In plants, toxic effects of chromium(VI) compounds are associated with the increased production of ROS and oxidative stress development as well as with inhibition of pigment synthesis and modification of virtually all cellular components. These metabolic changes result in inhibition of seed germination and seedling development as well as reduction of plant biomass and crop yield. However, if plants establish symbiosis with rhizobia, heavy metals are accumulated preferentially in nodules decreasing the toxicity of metals to the host plant. This review summarizes data on toxic effects of chromium on legume plants and legume-rhizobium symbiosis. In addition, we discussed the role of oxidative stress in both chromium toxicity and formation of rhizobial symbiosis and use of nodule bacteria for minimizing toxic effects of chromium on plants.
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37
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Checcucci A, DiCenzo GC, Bazzicalupo M, Mengoni A. Trade, Diplomacy, and Warfare: The Quest for Elite Rhizobia Inoculant Strains. Front Microbiol 2017; 8:2207. [PMID: 29170661 PMCID: PMC5684177 DOI: 10.3389/fmicb.2017.02207] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 10/26/2017] [Indexed: 01/12/2023] Open
Abstract
Rhizobia form symbiotic nitrogen-fixing nodules on leguminous plants, which provides an important source of fixed nitrogen input into the soil ecosystem. The improvement of symbiotic nitrogen fixation is one of the main challenges facing agriculture research. Doing so will reduce the usage of chemical nitrogen fertilizer, contributing to the development of sustainable agriculture practices to deal with the increasing global human population. Sociomicrobiological studies of rhizobia have become a model for the study of the evolution of mutualistic interactions. The exploitation of the wide range of social interactions rhizobia establish among themselves, with the soil and root microbiota, and with the host plant, could constitute a great advantage in the development of a new generation of highly effective rhizobia inoculants. Here, we provide a brief overview of the current knowledge on three main aspects of rhizobia interaction: trade of fixed nitrogen with the plant; diplomacy in terms of communication and possible synergistic effects; and warfare, as antagonism and plant control over symbiosis. Then, we propose new areas of investigation and the selection of strains based on the combination of the genetic determinants for the relevant rhizobia symbiotic behavioral phenotypes.
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Affiliation(s)
- Alice Checcucci
- Department of Biology, University of Florence, Florence, Italy
| | | | | | - Alessio Mengoni
- Department of Biology, University of Florence, Florence, Italy
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Chen Y, Li F, Tian L, Huang M, Deng R, Li X, Chen W, Wu P, Li M, Jiang H, Wu G. The Phenylalanine Ammonia Lyase Gene LjPAL1 Is Involved in Plant Defense Responses to Pathogens and Plays Diverse Roles in Lotus japonicus-Rhizobium Symbioses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:739-753. [PMID: 28598263 DOI: 10.1094/mpmi-04-17-0080-r] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Phenylalanine ammonia lyase (PAL) is important in the biosynthesis of plant secondary metabolites that regulate growth responses. Although its function is well-established in various plants, the functional significance of PAL genes in nodulation is poorly understood. Here, we demonstrate that the Lotus japonicus PAL (LjPAL1) gene is induced by Mesorhizobium loti infection and methyl-jasmonate (Me-JA) treatment in roots. LjPAL1 altered PAL activity, leading to changes in lignin contents and thicknesses of cell walls in roots and nodules of transgenic plants and, hence, to structural changes in roots and nodules. LjPAL1-knockdown plants (LjPAL1i) exhibited increased infection thread and nodule numbers and the induced upregulation of nodulin gene expression after M. loti infection. Conversely, LjPAL1 overexpression delayed the infection process and reduced infection thread and nodule numbers after M. loti inoculation. LjPAL1i plants also exhibited reduced endogenous salicylic acid (SA) accumulation and expression of the SA-dependent marker gene. Their infection phenotype could be partially restored by exogenous SA or Me-JA application. Our data demonstrate that LjPAL1 plays diverse roles in L. japonicus-rhizobium symbiosis, affecting rhizobial infection progress and nodule structure, likely by inducing lignin modification, regulating endogenous SA biosynthesis, and modulating SA signaling.
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Affiliation(s)
- Yaping Chen
- 1 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- 2 Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden; and
| | - Fengjiao Li
- 1 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- 2 Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden; and
- 3 University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lu Tian
- 1 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- 2 Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden; and
- 3 University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mingchao Huang
- 1 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- 2 Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden; and
- 3 University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rufang Deng
- 1 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- 2 Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden; and
| | - Xueliu Li
- 1 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- 2 Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden; and
- 3 University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Chen
- 1 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- 2 Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden; and
- 3 University of Chinese Academy of Sciences, Beijing 100049, China
| | - Pingzhi Wu
- 1 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- 2 Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden; and
| | - Meiru Li
- 1 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- 2 Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden; and
| | - Huawu Jiang
- 1 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- 2 Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden; and
| | - Guojiang Wu
- 1 Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- 2 Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden; and
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Kassaw T, Nowak S, Schnabel E, Frugoli J. ROOT DETERMINED NODULATION1 Is Required for M. truncatula CLE12, But Not CLE13, Peptide Signaling through the SUNN Receptor Kinase. PLANT PHYSIOLOGY 2017; 174:2445-2456. [PMID: 28592666 PMCID: PMC5543944 DOI: 10.1104/pp.17.00278] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 06/01/2017] [Indexed: 05/06/2023]
Abstract
The combinatorial interaction of a receptor kinase and a modified CLE peptide is involved in several developmental processes in plants, including autoregulation of nodulation (AON), which allows legumes to limit the number of root nodules formed based on available nitrogen and previous rhizobial colonization. Evidence supports the modification of CLE peptides by enzymes of the hydroxyproline O-arabinosyltransferase (HPAT/RDN) family. Here, we show by grafting and genetic analysis in Medicago truncatula that, in the AON pathway, RDN1, functioning in the root, acts upstream of the receptor kinase SUNN, functioning in the shoot. As expected for a glycosyltransferase, we found that RDN1 and RDN2 proteins are localized to the Golgi, as was shown previously for AtHPAT1. Using composite plants with transgenic hairy roots, we show that RDN1 and RDN2 orthologs from dicots as well as a related RDN gene from rice (Oryza sativa) can rescue the phenotype of rdn1-2 when expressed constitutively, but the less related MtRDN3 cannot. The timing of the induction of MtCLE12 and MtCLE13 peptide genes (negative regulators of AON) in nodulating roots is not altered by the mutation of RDN1 or SUNN, although expression levels are higher. Plants with transgenic roots constitutively expressing MtCLE12 require both RDN1 and SUNN to prevent nodule formation, while plants constitutively expressing MtCLE13 require only SUNN, suggesting that the two CLEs have different requirements for function. Combined with previous work, these data support a model in which RDN1 arabinosylates MtCLE12, and this modification is necessary for the transport and/or reception of the AON signal by the SUNN kinase.
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Affiliation(s)
- Tessema Kassaw
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina 29630
| | - Stephen Nowak
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina 29630
| | - Elise Schnabel
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina 29630
| | - Julia Frugoli
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina 29630
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Cao Y, Halane MK, Gassmann W, Stacey G. The Role of Plant Innate Immunity in the Legume-Rhizobium Symbiosis. ANNUAL REVIEW OF PLANT BIOLOGY 2017; 68:535-561. [PMID: 28142283 DOI: 10.1146/annurev-arplant-042916-041030] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A classic view of the evolution of mutualism is that it derives from a pathogenic relationship that attenuated over time to a situation in which both partners can benefit. If this is the case for rhizobia, then one might uncover features of the symbiosis that reflect this earlier pathogenic state. For example, as with plant pathogens, it is now generally assumed that rhizobia actively suppress the host immune response to allow infection and symbiosis establishment. Likewise, the host has retained mechanisms to control the nutrient supply to the symbionts and the number of nodules so that they do not become too burdensome. The open question is whether such events are strictly ancillary to the central symbiotic nodulation factor signaling pathway or are essential for rhizobial host infection. Subsequent to these early infection events, plant immune responses can also be induced inside nodules and likely play a role in, for example, nodule senescence. Thus, a balanced regulation of innate immunity is likely required throughout rhizobial infection, symbiotic establishment, and maintenance. In this review, we discuss the significance of plant immune responses in the regulation of symbiotic associations with rhizobia, as well as rhizobial evasion of the host immune system.
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Affiliation(s)
- Yangrong Cao
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Morgan K Halane
- Division of Plant Sciences, C.S. Bond Life Sciences Center, and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri 65211
| | - Walter Gassmann
- Division of Plant Sciences, C.S. Bond Life Sciences Center, and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri 65211
| | - Gary Stacey
- Division of Plant Sciences, C.S. Bond Life Sciences Center, and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri 65211
- Division of Biochemistry, University of Missouri, Columbia, Missouri 65211;
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Ghosh PK, Maiti TK. Structure of Extracellular Polysaccharides (EPS) Produced by Rhizobia and their Functions in Legume–Bacteria Symbiosis: — A Review. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.als.2016.11.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Grote J, Krysciak D, Petersen K, Güllert S, Schmeisser C, Förstner KU, Krishnan HB, Schwalbe H, Kubatova N, Streit WR. The Absence of the N-acyl-homoserine-lactone Autoinducer Synthase Genes traI and ngrI Increases the Copy Number of the Symbiotic Plasmid in Sinorhizobium fredii NGR234. Front Microbiol 2016; 7:1858. [PMID: 27917168 PMCID: PMC5114275 DOI: 10.3389/fmicb.2016.01858] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 11/04/2016] [Indexed: 01/24/2023] Open
Abstract
Plant-released flavonoids induce the transcription of symbiotic genes in rhizobia and one of the first bacterial responses is the synthesis of so called Nod factors. They are responsible for the initial root hair curling during onset of root nodule development. This signal exchange is believed to be essential for initiating the plant symbiosis with rhizobia affiliated with the Alphaproteobacteria. Here, we provide evidence that in the broad host range strain Sinorhizobium fredii NGR234 the complete lack of quorum sensing molecules results in an elevated copy number of its symbiotic plasmid (pNGR234a). This in turn triggers the expression of symbiotic genes and the production of Nod factors in the absence of plant signals. Therefore, increasing the copy number of specific plasmids could be a widespread mechanism of specialized bacterial populations to bridge gaps in signaling cascades.
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Affiliation(s)
- Jessica Grote
- Department of Microbiology and Biotechnology, Biocenter Klein Flottbek, University of Hamburg Hamburg, Germany
| | - Dagmar Krysciak
- Department of Microbiology and Biotechnology, Biocenter Klein Flottbek, University of Hamburg Hamburg, Germany
| | - Katrin Petersen
- Department of Microbiology and Biotechnology, Biocenter Klein Flottbek, University of Hamburg Hamburg, Germany
| | - Simon Güllert
- Department of Microbiology and Biotechnology, Biocenter Klein Flottbek, University of Hamburg Hamburg, Germany
| | - Christel Schmeisser
- Department of Microbiology and Biotechnology, Biocenter Klein Flottbek, University of Hamburg Hamburg, Germany
| | - Konrad U Förstner
- Core Unit Systems Medicine, University of Würzburg Würzburg, Germany
| | - Hari B Krishnan
- Plant Genetics Research Unit, Agricultural Research Service, United States Department of Agriculture, University of Missouri Columbia, MO, USA
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance Johann Wolfgang Goethe-University Frankfurt, Germany
| | - Nina Kubatova
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance Johann Wolfgang Goethe-University Frankfurt, Germany
| | - Wolfgang R Streit
- Department of Microbiology and Biotechnology, Biocenter Klein Flottbek, University of Hamburg Hamburg, Germany
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del Cerro P, Rolla-Santos AAP, Valderrama-Fernández R, Gil-Serrano A, Bellogín RA, Gomes DF, Pérez-Montaño F, Megías M, Hungría M, Ollero FJ. NrcR, a New Transcriptional Regulator of Rhizobium tropici CIAT 899 Involved in the Legume Root-Nodule Symbiosis. PLoS One 2016; 11:e0154029. [PMID: 27096734 PMCID: PMC4838322 DOI: 10.1371/journal.pone.0154029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 04/07/2016] [Indexed: 11/19/2022] Open
Abstract
The establishment of nitrogen-fixing rhizobium-legume symbioses requires a highly complex cascade of events. In this molecular dialogue the bacterial NodD transcriptional regulators in conjunction with plant inducers, mostly flavonoids, are responsible for the biosynthesis and secretion of Nod factors which are key molecules for successful nodulation. Other transcriptional regulators related to the symbiotic process have been identified in rhizobial genomes, including negative regulators such as NolR. Rhizobium tropici CIAT 899 is an important symbiont of common bean (Phaseolus vulgaris L.), and its genome encompasses intriguing features such as five copies of nodD genes, as well as other possible transcriptional regulators including the NolR protein. Here we describe and characterize a new regulatory gene located in the non-symbiotic plasmid pRtrCIAT899c, that shows homology (46% identity) with the nolR gene located in the chromosome of CIAT 899. The mutation of this gene, named nrcR (nolR-like plasmid c Regulator), enhanced motility and exopolysaccharide production in comparison to the wild-type strain. Interestingly, the number and decoration of Nod Factors produced by this mutant were higher than those detected in the wild-type strain, especially under salinity stress. The nrcR mutant showed delayed nodulation and reduced competitiveness with P. vulgaris, and reduction in nodule number and shoot dry weight in both P. vulgaris and Leucaena leucocephala. Moreover, the mutant exhibited reduced capacity to induce the nodC gene in comparison to the wild-type CIAT 899. The finding of a new nod-gene regulator located in a non-symbiotic plasmid may reveal the existence of even more complex mechanisms of regulation of nodulation genes in R. tropici CIAT 899 that may be applicable to other rhizobial species.
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Affiliation(s)
- Pablo del Cerro
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla. Sevilla, Spain
| | | | | | - Antonio Gil-Serrano
- Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla. Sevilla, Spain
| | - Ramón A. Bellogín
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla. Sevilla, Spain
| | | | | | - Manuel Megías
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla. Sevilla, Spain
| | | | - Francisco Javier Ollero
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla. Sevilla, Spain
- * E-mail:
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Geurts R, Xiao TT, Reinhold-Hurek B. What Does It Take to Evolve A Nitrogen-Fixing Endosymbiosis? TRENDS IN PLANT SCIENCE 2016; 21:199-208. [PMID: 26850795 DOI: 10.1016/j.tplants.2016.01.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/07/2016] [Accepted: 01/08/2016] [Indexed: 05/08/2023]
Abstract
Plant rhizo- and phyllospheres are exposed to a plethora of nitrogen-fixing bacteria, providing opportunities for the establishment of symbiotic associations. Nitrogen-fixing endosymbioses are most profitable and have evolved more than ten times in the angiosperms. This suggests that the evolutionary trajectory towards endosymbiosis is not complex. Here, we argue that microbe-induced cell divisions are a prerequisite for the entrance of diazotrophic prokaryotes into living plant cells. For rhizobia and Frankia bacteria, this is achieved by adapting the readout of the common symbiosis signalling pathway, such that cell divisions are induced. The common symbiosis signalling pathway is conserved in the plant kingdom and is required to establish an endosymbiosis with mycorrhizal fungi. We also discuss the adaptations that may have occurred that allowed nitrogen-fixing root nodule endosymbiosis.
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Affiliation(s)
- Rene Geurts
- Wageningen University, Department of Plant Science, Laboratory of Molecular Biology, Droevendaalsesteeg 1, 6708PB, The Netherlands.
| | - Ting Ting Xiao
- Wageningen University, Department of Plant Science, Laboratory of Molecular Biology, Droevendaalsesteeg 1, 6708PB, The Netherlands
| | - Barbara Reinhold-Hurek
- Department of Microbe-Plant Interaction, Faculty 2, University of Bremen, PO Box 33 04 40, 28334 Bremen, Germany.
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The extracellular polysaccharide produced by Enterobacter spp. isolated from root nodules of Abrus precatorius L. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2016. [DOI: 10.1016/j.bcab.2015.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Hewitt DKL, Mills G, Hayes F, Norris D, Coyle M, Wilkinson S, Davies W. N-fixation in legumes--An assessment of the potential threat posed by ozone pollution. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 208:909-18. [PMID: 26385644 DOI: 10.1016/j.envpol.2015.09.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 09/04/2015] [Indexed: 06/05/2023]
Abstract
The growth, development and functioning of legumes are often significantly affected by exposure to tropospheric ozone (O3) pollution. However, surprisingly little is known about how leguminous Nitrogen (N) fixation responds to ozone, with a scarcity of studies addressing this question in detail. In the last decade, ozone impacts on N-fixation in soybean, cowpea, mung bean, peanut and clover have been shown for concentrations which are now commonly recorded in ambient air or are likely to occur in the near future. We provide a synthesis of the existing literature addressing this issue, and also explore the effects that may occur on an agroecosystem scale by predicting reductions in Trifolium (clovers) root nodule biomass in United Kingdom (UK) pasture based on ozone concentration data for a "high" (2006) and "average" ozone year (2008). Median 8% and 5% reductions in clover root nodule biomass in pasture across the UK were predicted for 2006 and 2008 respectively. Seasonal exposure to elevated ozone, or short-term acute concentrations >100 ppb, are sufficient to reduce N-fixation and/or impact nodulation, in a range of globally-important legumes. However, an increasing global burden of CO2, the use of artificial fertiliser, and reactive N-pollution may partially mitigate impacts of ozone on N-fixation.
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Affiliation(s)
- D K L Hewitt
- Centre for Ecology & Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd, LL57 2UW, UK; Lancaster University, Lancaster Environment Centre, Lancaster, Lancashire, LA1 4YQ, UK.
| | - G Mills
- Centre for Ecology & Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd, LL57 2UW, UK
| | - F Hayes
- Centre for Ecology & Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd, LL57 2UW, UK
| | - D Norris
- Centre for Ecology & Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd, LL57 2UW, UK
| | - M Coyle
- Centre for Ecology & Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB, UK
| | - S Wilkinson
- Lancaster University, Lancaster Environment Centre, Lancaster, Lancashire, LA1 4YQ, UK
| | - W Davies
- Lancaster University, Lancaster Environment Centre, Lancaster, Lancashire, LA1 4YQ, UK
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Opening the "black box" of nodD3, nodD4 and nodD5 genes of Rhizobium tropici strain CIAT 899. BMC Genomics 2015; 16:864. [PMID: 26502986 PMCID: PMC4624370 DOI: 10.1186/s12864-015-2033-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 10/08/2015] [Indexed: 11/15/2022] Open
Abstract
Background Transcription of nodulation genes in rhizobial species is orchestrated by the regulatory nodD gene. Rhizobium tropici strain CIAT 899 is an intriguing species in possessing features such as broad host range, high tolerance of abiotic stresses and, especially, by carrying the highest known number of nodD genes—five—and the greatest diversity of Nod factors (lipochitooligosaccharides, LCOs). Here we shed light on the roles of the multiple nodD genes of CIAT 899 by reporting, for the first time, results obtained with nodD3, nodD4 and nodD5 mutants. Methods The three nodD mutants were built by insertion of Ω interposon. Nod factors were purified and identified by LC-MS/MS analyses. In addition, nodD1 and nodC relative gene expressions were measured by quantitative RT-PCR in the wt and derivative mutant strains. Phenotypic traits such as exopolysaccharide (EPS), lipopolysaccharide (LPS), swimming and swarming motilities, biofilm formation and indole acetid acid (IAA) production were also perfomed. All these experiments were carried out in presence of both inducers of CIAT 899, apigenin and salt. Finally, nodulation assays were evaluated in up to six different legumes, including common bean (Phaseolus vulgaris L.). Results Phenotypic and symbiotic properties, Nod factors and gene expression of nodD3, nodD4 and nodD5 mutants were compared with those of the wild-type (WT) CIAT 899, both in the presence and in the absence of the nod-gene-inducing molecule apigenin and of saline stress. No differences between the mutants and the WT were observed in exopolysaccharide (EPS) and lipopolysaccharide (LPS) profiles, motility, indole acetic acid (IAA) synthesis or biofilm production, either in the presence, or in the absence of inducers. Nodulation studies demonstrated the most complex regulatory system described so far, requiring from one (Leucaena leucocephala, Lotus burtii) to four (Lotus japonicus) nodD genes. Up to 38 different structures of Nod factors were detected, being higher under salt stress, except for the nodD5 mutant; in addition, a high number of structures was synthesized by the nodD4 mutant in the absence of any inducer. Probable activator (nodD3 and nodD5) or repressor roles (nodD4), possibly via nodD1 and/or nodD2, were attributed to the three nodD genes. Expression of nodC, nodD1 and each nodD studied by RT-qPCR confirmed that nodD3 is an activator of nodD1, both in the presence of apigenin and salt stress. In contrast, nodD4 might be an inducer with apigenin and a repressor under saline stress, whereas nodD5 was an inducer under both conditions. Conclusions We report for R. tropici CIAT 899 the most complex model of regulation of nodulation genes described so far. Five nodD genes performed different roles depending on the host plant and the inducing environment. Nodulation required from one to four nodD genes, depending on the host legume. nodD3 and nodD5 were identified as activators of the nodD1 gene, whereas, for the first time, it was shown that a regulatory nodD gene—nodD4—might act as repressor or inducer, depending on the inducing environment, giving support to the hypothesis that nodD roles go beyond nodulation, in terms of responses to abiotic stresses. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2033-z) contains supplementary material, which is available to authorized users.
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Nguyen TT, Volkening JD, Rose CM, Venkateshwaran M, Westphall MS, Coon JJ, Ané JM, Sussman MR. Potential regulatory phosphorylation sites in a Medicago truncatula plasma membrane proton pump implicated during early symbiotic signaling in roots. FEBS Lett 2015; 589:2186-93. [PMID: 26188545 PMCID: PMC5991090 DOI: 10.1016/j.febslet.2015.06.035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 06/22/2015] [Accepted: 06/24/2015] [Indexed: 10/23/2022]
Abstract
In plants and fungi the plasma membrane proton pump generates a large proton-motive force that performs essential functions in many processes, including solute transport and the control of cell elongation. Previous studies in yeast and higher plants have indicated that phosphorylation of an auto-inhibitory domain is involved in regulating pump activity. In this report we examine the Medicago truncatula plasma membrane proton pump gene family, and in particular MtAHA5. Yeast complementation assays with phosphomimetic mutations at six candidate sites support a phosphoregulatory role for two residues, suggesting a molecular model to explain early Nod factor-induced changes in the plasma membrane proton-motive force of legume root cells.
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Affiliation(s)
- Thao T Nguyen
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States; Biotechnology Center, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Jeremy D Volkening
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States; Biotechnology Center, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Christopher M Rose
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States; Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Muthusubramanian Venkateshwaran
- Department of Agronomy, University of Wisconsin-Madison, Madison, WI 53706, United States; School of Agriculture, University of Wisconsin-Platteville, Platteville, WI 53818, United States
| | - Michael S Westphall
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States; Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Joshua J Coon
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States; Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI 53706, United States; Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Jean-Michel Ané
- Department of Agronomy, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Michael R Sussman
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States; Biotechnology Center, University of Wisconsin-Madison, Madison, WI 53706, United States.
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Mariangela H, Marco AN, Ricardo SA. Alternative methods of soybean inoculation to overcome adverse conditions at sowing. ACTA ACUST UNITED AC 2015. [DOI: 10.5897/ajar2014.8687] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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del Cerro P, Rolla-Santos AAP, Gomes DF, Marks BB, Pérez-Montaño F, Rodríguez-Carvajal MÁ, Nakatani AS, Gil-Serrano A, Megías M, Ollero FJ, Hungria M. Regulatory nodD1 and nodD2 genes of Rhizobium tropici strain CIAT 899 and their roles in the early stages of molecular signaling and host-legume nodulation. BMC Genomics 2015; 16:251. [PMID: 25880529 PMCID: PMC4393855 DOI: 10.1186/s12864-015-1458-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 03/09/2015] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Nodulation and symbiotic nitrogen fixation are mediated by several genes, both of the host legume and of the bacterium. The rhizobial regulatory nodD gene plays a critical role, orchestrating the transcription of the other nodulation genes. Rhizobium tropici strain CIAT 899 is an effective symbiont of several legumes-with an emphasis on common bean (Phaseolus vulgaris)-and is unusual in carrying multiple copies of nodD, the roles of which remain to be elucidated. RESULTS Phenotypes, Nod factors and gene expression of nodD1 and nodD2 mutants of CIAT 899 were compared with those of the wild type strain, both in the presence and in the absence of the nod-gene-inducing molecules apigenin and salt (NaCl). Differences between the wild type and mutants were observed in swimming motility and IAA (indole acetic acid) synthesis. In the presence of both apigenin and salt, large numbers of Nod factors were detected in CIAT 899, with fewer detected in the mutants. nodC expression was lower in both mutants; differences in nodD1 and nodD2 expression were observed between the wild type and the mutants, with variation according to the inducing molecule, and with a major role of apigenin with nodD1 and of salt with nodD2. In the nodD1 mutant, nodulation was markedly reduced in common bean and abolished in leucaena (Leucaena leucocephala) and siratro (Macroptilium atropurpureum), whereas a mutation in nodD2 reduced nodulation in common bean, but not in the other two legumes. CONCLUSION Our proposed model considers that full nodulation of common bean by R. tropici requires both nodD1 and nodD2, whereas, in other legume species that might represent the original host, nodD1 plays the major role. In general, nodD2 is an activator of nod-gene transcription, but, in specific conditions, it can slightly repress nodD1. nodD1 and nodD2 play other roles beyond nodulation, such as swimming motility and IAA synthesis.
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Affiliation(s)
- Pablo del Cerro
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avda. Reina Mercedes, 6 Apdo Postal 41012, Sevilla, Spain.
| | | | | | | | - Francisco Pérez-Montaño
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avda. Reina Mercedes, 6 Apdo Postal 41012, Sevilla, Spain.
| | | | | | - Antonio Gil-Serrano
- Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla, Apdo Postal 553, 41071, Sevilla, Spain.
| | - Manuel Megías
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avda. Reina Mercedes, 6 Apdo Postal 41012, Sevilla, Spain.
| | - Francisco Javier Ollero
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avda. Reina Mercedes, 6 Apdo Postal 41012, Sevilla, Spain.
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