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Klonowska A, Ardley J, Moulin L, Zandberg J, Patrel D, Gollagher M, Marinova D, Reddy TBK, Varghese N, Huntemann M, Woyke T, Seshadri R, Ivanova N, Kyrpides N, Reeve W. Discovery of a novel filamentous prophage in the genome of the Mimosa pudica microsymbiont Cupriavidus taiwanensis STM 6018. Front Microbiol 2023; 14:1082107. [PMID: 36925474 PMCID: PMC10011098 DOI: 10.3389/fmicb.2023.1082107] [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: 10/27/2022] [Accepted: 01/24/2023] [Indexed: 03/08/2023] Open
Abstract
Integrated virus genomes (prophages) are commonly found in sequenced bacterial genomes but have rarely been described in detail for rhizobial genomes. Cupriavidus taiwanensis STM 6018 is a rhizobial Betaproteobacteria strain that was isolated in 2006 from a root nodule of a Mimosa pudica host in French Guiana, South America. Here we describe features of the genome of STM 6018, focusing on the characterization of two different types of prophages that have been identified in its genome. The draft genome of STM 6018 is 6,553,639 bp, and consists of 80 scaffolds, containing 5,864 protein-coding genes and 61 RNA genes. STM 6018 contains all the nodulation and nitrogen fixation gene clusters common to symbiotic Cupriavidus species; sharing >99.97% bp identity homology to the nod/nif/noeM gene clusters from C. taiwanensis LMG19424T and "Cupriavidus neocalidonicus" STM 6070. The STM 6018 genome contains the genomes of two prophages: one complete Mu-like capsular phage and one filamentous phage, which integrates into a putative dif site. This is the first characterization of a filamentous phage found within the genome of a rhizobial strain. Further examination of sequenced rhizobial genomes identified filamentous prophage sequences in several Beta-rhizobial strains but not in any Alphaproteobacterial rhizobia.
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Affiliation(s)
- Agnieszka Klonowska
- Université de Montpellier, IRD, CIRAD, INRAE, Institut AgroPHIM Plant Health Institute, Montpellier, France
| | - Julie Ardley
- Centre for Crop and Food Innovation, Food Futures Institute, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, WA, Australia
| | - Lionel Moulin
- Université de Montpellier, IRD, CIRAD, INRAE, Institut AgroPHIM Plant Health Institute, Montpellier, France
| | - Jaco Zandberg
- Centre for Crop and Food Innovation, Food Futures Institute, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, WA, Australia
| | - Delphine Patrel
- Université de Montpellier, IRD, CIRAD, INRAE, Institut AgroPHIM Plant Health Institute, Montpellier, France
| | - Margaret Gollagher
- Curtin University Sustainability Policy Institute, Curtin University, Bentley, WA, Australia
| | - Dora Marinova
- Curtin University Sustainability Policy Institute, Curtin University, Bentley, WA, Australia
| | - T B K Reddy
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Neha Varghese
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Marcel Huntemann
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Tanja Woyke
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Rekha Seshadri
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Natalia Ivanova
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Nikos Kyrpides
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Wayne Reeve
- Centre for Crop and Food Innovation, Food Futures Institute, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, WA, Australia
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Jiménez-Guerrero I, Medina C, Vinardell JM, Ollero FJ, López-Baena FJ. The Rhizobial Type 3 Secretion System: The Dr. Jekyll and Mr. Hyde in the Rhizobium–Legume Symbiosis. Int J Mol Sci 2022; 23:ijms231911089. [PMID: 36232385 PMCID: PMC9569860 DOI: 10.3390/ijms231911089] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/08/2022] [Accepted: 09/14/2022] [Indexed: 01/14/2023] Open
Abstract
Rhizobia are soil bacteria that can establish a symbiotic association with legumes. As a result, plant nodules are formed on the roots of the host plants where rhizobia differentiate to bacteroids capable of fixing atmospheric nitrogen into ammonia. This ammonia is transferred to the plant in exchange of a carbon source and an appropriate environment for bacterial survival. This process is subjected to a tight regulation with several checkpoints to allow the progression of the infection or its restriction. The type 3 secretion system (T3SS) is a secretory system that injects proteins, called effectors (T3E), directly into the cytoplasm of the host cell, altering host pathways or suppressing host defense responses. This secretion system is not present in all rhizobia but its role in symbiosis is crucial for some symbiotic associations, showing two possible faces as Dr. Jekyll and Mr. Hyde: it can be completely necessary for the formation of nodules, or it can block nodulation in different legume species/cultivars. In this review, we compile all the information currently available about the effects of different rhizobial effectors on plant symbiotic phenotypes. These phenotypes are diverse and highlight the importance of the T3SS in certain rhizobium–legume symbioses.
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Teulet A, Camuel A, Perret X, Giraud E. The Versatile Roles of Type III Secretion Systems in Rhizobia-Legume Symbioses. Annu Rev Microbiol 2022; 76:45-65. [PMID: 35395168 DOI: 10.1146/annurev-micro-041020-032624] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To suppress plant immunity and promote the intracellular infection required for fixing nitrogen for the benefit of their legume hosts, many rhizobia use type III secretion systems (T3SSs) that deliver effector proteins (T3Es) inside host cells. As reported for interactions between pathogens and host plants, the immune system of legume hosts and the cocktail of T3Es secreted by rhizobia determine the symbiotic outcome. If they remain undetected, T3Es may reduce plant immunity and thus promote infection of legumes by rhizobia. If one or more of the secreted T3Es are recognized by the cognate plant receptors, defense responses are triggered and rhizobial infection may abort. However, some rhizobial T3Es can also circumvent the need for nodulation (Nod) factors to trigger nodule formation. Here we review the multifaceted roles played by rhizobial T3Es during symbiotic interactions with legumes. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Albin Teulet
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), IRD, Institut Agro, INRAE, Université de Montpellier, and CIRAD, Montpellier, France;
| | - Alicia Camuel
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), IRD, Institut Agro, INRAE, Université de Montpellier, and CIRAD, Montpellier, France; .,PHIM Plant Health Institute, IRD, Institut Agro, INRAE, Université de Montpellier, and CIRAD, Montpellier, France
| | - Xavier Perret
- Laboratory of Microbial Genetics, Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Eric Giraud
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), IRD, Institut Agro, INRAE, Université de Montpellier, and CIRAD, Montpellier, France; .,PHIM Plant Health Institute, IRD, Institut Agro, INRAE, Université de Montpellier, and CIRAD, Montpellier, France
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Wakimoto T, Nakagishi S, Matsukawa N, Tani S, Kai K. A Unique Combination of Two Different Quorum Sensing Systems in the β-Rhizobium Cupriavidus taiwanensis. JOURNAL OF NATURAL PRODUCTS 2020; 83:1876-1884. [PMID: 32484353 DOI: 10.1021/acs.jnatprod.0c00054] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Cupriavidus taiwanensis LMG19424, a β-rhizobial symbiont of Mimosa pudica, harbors phc and tqs quorum sensing (QS), which are the homologous cell-cell communication systems previously identified from the plant pathogen Ralstonia solanacearum and the human pathogen Vibrio cholerae, respectively. However, there has been no experimental evidence reported that these QS systems function in C. taiwanensis LMG19424. We identified (R)-methyl 3-hydroxymyristate (3-OH MAME) and (S)-3-hydroxypentadecan-4-one (C15-AHK) as phc and tqs QS signals, respectively, and characterized these QS systems. The expression of the signal synthase gene phcB and tqsA in E. coli BL21(DE3) resulted in the high production of 3-OH MAME and C15-AHK, respectively. Their structures were elucidated by comparison of EI-MS data and GC/chiral LC retention times with synthetic standards. The deletion of phcB reduced cell motility and increased biofilm formation, and the double deletion of phcB/tqsA caused the accumulation of the metal chelator coproporphyrin III in its mutant culture. Although the deletion of phcB and tqsA slightly reduced its ability to nodulate on aseptically grown seedlings of M. pudica, there was no significant difference in nodule formation between LMG19424 and its QS mutants when commercial soils were used. Taken together, this is the first example of the simultaneous production of 3-OH MAME/C15-AHK as QS signals in a bacterial species, and the importance of the phc/tqs QS systems in the saprophytic stage of C. taiwanensis LMG19424 is suggested.
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Affiliation(s)
- Takayuki Wakimoto
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Shiori Nakagishi
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Nao Matsukawa
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Shuji Tani
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Kenji Kai
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
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Doin de Moura GG, Remigi P, Masson-Boivin C, Capela D. Experimental Evolution of Legume Symbionts: What Have We Learnt? Genes (Basel) 2020; 11:E339. [PMID: 32210028 PMCID: PMC7141107 DOI: 10.3390/genes11030339] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 03/17/2020] [Accepted: 03/20/2020] [Indexed: 12/11/2022] Open
Abstract
Rhizobia, the nitrogen-fixing symbionts of legumes, are polyphyletic bacteria distributed in many alpha- and beta-proteobacterial genera. They likely emerged and diversified through independent horizontal transfers of key symbiotic genes. To replay the evolution of a new rhizobium genus under laboratory conditions, the symbiotic plasmid of Cupriavidus taiwanensis was introduced in the plant pathogen Ralstonia solanacearum, and the generated proto-rhizobium was submitted to repeated inoculations to the C. taiwanensis host, Mimosa pudica L.. This experiment validated a two-step evolutionary scenario of key symbiotic gene acquisition followed by genome remodeling under plant selection. Nodulation and nodule cell infection were obtained and optimized mainly via the rewiring of regulatory circuits of the recipient bacterium. Symbiotic adaptation was shown to be accelerated by the activity of a mutagenesis cassette conserved in most rhizobia. Investigating mutated genes led us to identify new components of R. solanacearum virulence and C. taiwanensis symbiosis. Nitrogen fixation was not acquired in our short experiment. However, we showed that post-infection sanctions allowed the increase in frequency of nitrogen-fixing variants among a non-fixing population in the M. pudica-C. taiwanensis system and likely allowed the spread of this trait in natura. Experimental evolution thus provided new insights into rhizobium biology and evolution.
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Affiliation(s)
| | | | | | - Delphine Capela
- LIPM, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan 31320, France; (G.G.D.d.M.); (P.R.); (C.M.-B.)
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Alaswad AA, Oehrle NW, Krishnan HB. Classical Soybean ( Glycine max (L.) Merr) Symbionts, Sinorhizobium fredii USDA191 and Bradyrhizobium diazoefficiens USDA110, Reveal Contrasting Symbiotic Phenotype on Pigeon Pea ( Cajanus cajan (L.) Millsp). Int J Mol Sci 2019; 20:E1091. [PMID: 30832430 PMCID: PMC6429105 DOI: 10.3390/ijms20051091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 02/22/2019] [Accepted: 02/26/2019] [Indexed: 02/06/2023] Open
Abstract
Pigeon pea (Cajanus cajan (L.) Millspaugh) is cultivated widely in semiarid agricultural regions in over 90 countries around the world. This important legume can enter into symbiotic associations with a wide range of rhizobia including Bradyrhizobium and fast-growing rhizobia. In comparison with other major legumes such as soybean and common bean, only limited information is available on the symbiotic interaction of pigeon pea with rhizobia. In this study, we investigated the ability of two classical soybean symbionts-S. fredii USDA191 and B. diazoefficiens USDA110-and their type 3 secretion system (T3SS) mutants, to nodulate pigeon pea. Both S. fredii USDA191 and a T3SS mutant S. fredii RCB26 formed nitrogen-fixing nodules on pigeon pea. Inoculation of pigeon pea roots with B. diazoefficiens USDA110 and B. diazoefficiens Δ136 (a T3SS mutant) resulted in the formation of Fix- and Fix+ nodules, respectively. Light and transmission electron microscopy of Fix- nodules initiated by B. diazoefficiens USDA110 revealed the complete absence of rhizobia within these nodules. In contrast, Fix+ nodules formed by B. diazoefficiens Δ136 revealed a central region that was completely filled with rhizobia. Ultrastructural investigation revealed the presence of numerous bacteroids surrounded by peribacteroid membranes in the infected cells. Analysis of nodule proteins by one- and two-dimensional gel electrophoresis revealed that leghemoglobin was absent in B. diazoefficiens USDA110 nodules, while it was abundantly present in B. diazoefficiens Δ136 nodules. Results of competitive nodulation assays indicated that B. diazoefficiens Δ136 had greater competitiveness for nodulation on pigeon pea than did the wild type strain. Our results suggest that this T3SS mutant of B. diazoefficiens, due to its greater competitiveness and ability to form Fix+ nodules, could be exploited as a potential inoculant to boost pigeon pea productivity.
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Affiliation(s)
- Alaa A Alaswad
- Plant Science Division, University of Missouri, Columbia, MO 65211, USA.
- King Abdul Aziz University, 21589 Jeddah, Saudi Arabia.
| | - Nathan W Oehrle
- Plant Genetics Research Unit, USDA-Agricultural Research Service, Columbia, MO 65211, USA.
| | - Hari B Krishnan
- Plant Science Division, University of Missouri, Columbia, MO 65211, USA.
- Plant Genetics Research Unit, USDA-Agricultural Research Service, Columbia, MO 65211, USA.
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Parallels between experimental and natural evolution of legume symbionts. Nat Commun 2018; 9:2264. [PMID: 29891837 PMCID: PMC5995829 DOI: 10.1038/s41467-018-04778-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 05/11/2018] [Indexed: 12/29/2022] Open
Abstract
The emergence of symbiotic interactions has been studied using population genomics in nature and experimental evolution in the laboratory, but the parallels between these processes remain unknown. Here we compare the emergence of rhizobia after the horizontal transfer of a symbiotic plasmid in natural populations of Cupriavidus taiwanensis, over 10 MY ago, with the experimental evolution of symbiotic Ralstonia solanacearum for a few hundred generations. In spite of major differences in terms of time span, environment, genetic background, and phenotypic achievement, both processes resulted in rapid genetic diversification dominated by purifying selection. We observe no adaptation in the plasmid carrying the genes responsible for the ecological transition. Instead, adaptation was associated with positive selection in a set of genes that led to the co-option of the same quorum-sensing system in both processes. Our results provide evidence for similarities in experimental and natural evolutionary transitions and highlight the potential of comparisons between both processes to understand symbiogenesis. It is unclear if experimental evolution is a good model for natural processes. Here, Clerissi et al. find parallels between the evolution of symbiosis in rhizobia after horizontal transfer of a plasmid over 10 million years ago and experimentally evolved symbionts.
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Klonowska A, Melkonian R, Miché L, Tisseyre P, Moulin L. Transcriptomic profiling of Burkholderia phymatum STM815, Cupriavidus taiwanensis LMG19424 and Rhizobium mesoamericanum STM3625 in response to Mimosa pudica root exudates illuminates the molecular basis of their nodulation competitiveness and symbiotic evolutionary history. BMC Genomics 2018; 19:105. [PMID: 29378510 PMCID: PMC5789663 DOI: 10.1186/s12864-018-4487-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 01/17/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Rhizobial symbionts belong to the classes Alphaproteobacteria and Betaproteobacteria (called "alpha" and "beta"-rhizobia). Most knowledge on the genetic basis of symbiosis is based on model strains belonging to alpha-rhizobia. Mimosa pudica is a legume that offers an excellent opportunity to study the adaptation toward symbiotic nitrogen fixation in beta-rhizobia compared to alpha-rhizobia. In a previous study (Melkonian et al., Environ Microbiol 16:2099-111, 2014) we described the symbiotic competitiveness of M. pudica symbionts belonging to Burkholderia, Cupriavidus and Rhizobium species. RESULTS In this article we present a comparative analysis of the transcriptomes (by RNAseq) of B. phymatum STM815 (BP), C. taiwanensis LMG19424 (CT) and R. mesoamericanum STM3625 (RM) in conditions mimicking the early steps of symbiosis (i.e. perception of root exudates). BP exhibited the strongest transcriptome shift both quantitatively and qualitatively, which mirrors its high competitiveness in the early steps of symbiosis and its ancient evolutionary history as a symbiont, while CT had a minimal response which correlates with its status as a younger symbiont (probably via acquisition of symbiotic genes from a Burkholderia ancestor) and RM had a typical response of Alphaproteobacterial rhizospheric bacteria. Interestingly, the upregulation of nodulation genes was the only common response among the three strains; the exception was an up-regulated gene encoding a putative fatty acid hydroxylase, which appears to be a novel symbiotic gene specific to Mimosa symbionts. CONCLUSION The transcriptional response to root exudates was correlated to each strain nodulation competitiveness, with Burkholderia phymatum appearing as the best specialised symbiont of Mimosa pudica.
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Affiliation(s)
| | - Rémy Melkonian
- IRD, UMR LSTM, Campus de Baillarguet, Montpellier, France
| | - Lucie Miché
- IRD, UMR LSTM, Campus de Baillarguet, Montpellier, France.,Present address: Aix Marseille University, University of Avignon, CNRS, IRD, IMBE, Marseille, France
| | | | - Lionel Moulin
- IRD, Cirad, University of Montpellier, IPME, Montpellier, France.
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Abstract
Rhizobia are nitrogen-fixing bacteria that establish a nodule symbiosis with legumes. Nodule formation depends on signals and surface determinants produced by both symbiotic partners. Among them, rhizobial Nops (nodulation outer proteins) play a crucial symbiotic role in many strain-host combinations. Nops are defined as proteins secreted via a rhizobial T3SS (type III secretion system). Functional T3SSs have been characterized in many rhizobial strains. Nops have been identified using various genetic, biochemical, proteomic, genomic and experimental approaches. Certain Nops represent extracellular components of the T3SS, which are visible in electron micrographs as bacterial surface appendages called T3 (type III) pili. Other Nops are T3 effector proteins that can be translocated into plant cells. Rhizobial T3 effectors manipulate cellular processes in host cells to suppress plant defence responses against rhizobia and to promote symbiosis-related processes. Accordingly, mutant strains deficient in synthesis or secretion of T3 effectors show reduced symbiotic properties on certain host plants. On the other hand, direct or indirect recognition of T3 effectors by plant cells expressing specific R (resistance) proteins can result in effector triggered defence responses that negatively affect rhizobial infection. Hence Nops are double-edged swords that may promote establishment of symbiosis with one legume (symbiotic factors) and impair symbiotic processes when bacteria are inoculated on another legume species (asymbiotic factors). In the present review, we provide an overview of our current understanding of Nops. We summarize their symbiotic effects, their biochemical properties and their possible modes of action. Finally, we discuss future perspectives in the field of T3 effector research.
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Gourion B, Berrabah F, Ratet P, Stacey G. Rhizobium-legume symbioses: the crucial role of plant immunity. TRENDS IN PLANT SCIENCE 2015; 20:186-94. [PMID: 25543258 DOI: 10.1016/j.tplants.2014.11.008] [Citation(s) in RCA: 166] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 11/16/2014] [Accepted: 11/21/2014] [Indexed: 05/03/2023]
Abstract
New research results have significantly revised our understanding of the rhizobium-legume infection process. For example, Nod factors (NFs), previously thought to be absolutely essential for this symbiosis, were shown to be dispensable under particular conditions. Similarly, an NF receptor, previously considered to be solely involved in symbiosis, was shown to function during plant pathogen infections. Indeed, there is a growing realization that plant innate immunity is a crucial component in the establishment and maintenance of symbiosis. We review here the factors involved in the suppression of plant immunity during rhizobium-legume symbiosis, and we attempt to place this information into context with the most recent and sometimes surprising research results.
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Affiliation(s)
- Benjamin Gourion
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique (CNRS), Saclay Plant Sciences, Avenue de la terrasse, 91198 Gif-sur-Yvette CEDEX, France.
| | - Fathi Berrabah
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique (CNRS), Saclay Plant Sciences, Avenue de la terrasse, 91198 Gif-sur-Yvette CEDEX, France
| | - Pascal Ratet
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique (CNRS), Saclay Plant Sciences, Avenue de la terrasse, 91198 Gif-sur-Yvette CEDEX, France
| | - Gary Stacey
- Divisions of Plant Science and Biochemistry, National Center for Soybean Biotechnology, C.S. Bond Life Science Center, University of Missouri, Columbia, MO 65203, USA
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Limpens E, van Zeijl A, Geurts R. Lipochitooligosaccharides modulate plant host immunity to enable endosymbioses. ANNUAL REVIEW OF PHYTOPATHOLOGY 2015; 53:311-34. [PMID: 26047562 DOI: 10.1146/annurev-phyto-080614-120149] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Symbiotic nitrogen-fixing rhizobium bacteria and arbuscular mycorrhizal fungi use lipochitooligosaccharide (LCO) signals to communicate with potential host plants. Upon a compatible match, an intimate relation is established during which the microsymbiont is allowed to enter root (-derived) cells. Plants perceive microbial LCO molecules by specific LysM-domain-containing receptor-like kinases. These do not only activate a common symbiosis signaling pathway that is shared in both symbioses but also modulate innate immune responses. Recent studies revealed that symbiotic LCO receptors are closely related to chitin innate immune receptors, and some of these receptors even function in symbiosis as well as immunity. This raises questions about how plants manage to translate structurally very similar microbial signals into different outputs. Here, we describe the current view on chitin and LCO perception in innate immunity and endosymbiosis and question how LCOs might modulate the immune system. Furthermore, we discuss what it takes to become an endosymbiont.
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Affiliation(s)
- Erik Limpens
- Laboratory of Molecular Biology, Department of Plant Science, Wageningen University, 6708PB Wageningen, The Netherlands;
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Tampakaki AP. Commonalities and differences of T3SSs in rhizobia and plant pathogenic bacteria. FRONTIERS IN PLANT SCIENCE 2014; 5:114. [PMID: 24723933 PMCID: PMC3973906 DOI: 10.3389/fpls.2014.00114] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 03/11/2014] [Indexed: 05/19/2023]
Abstract
Plant pathogenic bacteria and rhizobia infect higher plants albeit the interactions with their hosts are principally distinct and lead to completely different phenotypic outcomes, either pathogenic or mutualistic, respectively. Bacterial protein delivery to plant host plays an essential role in determining the phenotypic outcome of plant-bacteria interactions. The involvement of type III secretion systems (T3SSs) in mediating animal- and plant-pathogen interactions was discovered in the mid-80's and is now recognized as a multiprotein nanomachine dedicated to trans-kingdom movement of effector proteins. The discovery of T3SS in bacteria with symbiotic lifestyles broadened its role beyond virulence. In most T3SS-positive bacterial pathogens, virulence is largely dependent on functional T3SSs, while in rhizobia the system is dispensable for nodulation and can affect positively or negatively the mutualistic associations with their hosts. This review focuses on recent comparative genome analyses in plant pathogens and rhizobia that uncovered similarities and variations among T3SSs in their genetic organization, regulatory networks and type III secreted proteins and discusses the evolutionary adaptations of T3SSs and type III secreted proteins that might account for the distinguishable phenotypes and host range characteristics of plant pathogens and symbionts.
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Affiliation(s)
- Anastasia P. Tampakaki
- *Correspondence: Anastasia P. Tampakaki, Laboratory of General and Agricultural Microbiology, Department of Crop Science, Agricultural University of Athens, Iera Odos 75, Votanikos, 11855, Athens, Greece e-mail:
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