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Syska C, Kiers A, Rancurel C, Bailly-Bechet M, Lipuma J, Alloing G, Garcia I, Dupont L. VapC10 toxin of the legume symbiont Sinorhizobium meliloti targets tRNASer and controls intracellular lifestyle. THE ISME JOURNAL 2024; 18:wrae015. [PMID: 38365913 PMCID: PMC10945364 DOI: 10.1093/ismejo/wrae015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/05/2024] [Accepted: 01/25/2024] [Indexed: 02/18/2024]
Abstract
The soil bacterium Sinorhizobium meliloti can establish a nitrogen-fixing symbiosis with the model legume Medicago truncatula. The rhizobia induce the formation of a specialized root organ called nodule, where they differentiate into bacteroids and reduce atmospheric nitrogen into ammonia. Little is known on the mechanisms involved in nodule senescence onset and in bacteroid survival inside the infected plant cells. Although toxin-antitoxin (TA) systems have been shown to promote intracellular survival within host cells in human pathogenic bacteria, their role in symbiotic bacteria was rarely investigated. S. meliloti encodes several TA systems, mainly of the VapBC family. Here we present the functional characterization, through a multidisciplinary approach, of the VapBC10 TA system of S. meliloti. Following a mapping by overexpression of an RNase in Escherichia coli (MORE) RNA-seq analysis, we demonstrated that the VapC10 toxin is an RNase that cleaves the anticodon loop of two tRNASer. Thereafter, a bioinformatics approach was used to predict VapC10 targets in bacteroids. This analysis suggests that toxin activation triggers a specific proteome reprogramming that could limit nitrogen fixation capability and viability of bacteroids. Accordingly, a vapC10 mutant induces a delayed senescence in nodules, associated to an enhanced bacteroid survival. VapBC10 TA system could contribute to S. meliloti adaptation to symbiotic lifestyle, in response to plant nitrogen status.
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Affiliation(s)
- Camille Syska
- Université Côte d'Azur, INRAE, CNRS, Institut Sophia Agrobiotech (ISA), Sophia Antipolis 06903, France
| | - Aurélie Kiers
- Université Côte d'Azur, INRAE, CNRS, Institut Sophia Agrobiotech (ISA), Sophia Antipolis 06903, France
| | - Corinne Rancurel
- Université Côte d'Azur, INRAE, CNRS, Institut Sophia Agrobiotech (ISA), Sophia Antipolis 06903, France
| | - Marc Bailly-Bechet
- Université Côte d'Azur, INRAE, CNRS, Institut Sophia Agrobiotech (ISA), Sophia Antipolis 06903, France
| | | | - Geneviève Alloing
- Université Côte d'Azur, INRAE, CNRS, Institut Sophia Agrobiotech (ISA), Sophia Antipolis 06903, France
| | - Isabelle Garcia
- Université Côte d'Azur, INRAE, CNRS, Institut Sophia Agrobiotech (ISA), Sophia Antipolis 06903, France
| | - Laurence Dupont
- Université Côte d'Azur, INRAE, CNRS, Institut Sophia Agrobiotech (ISA), Sophia Antipolis 06903, France
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Zamakhaev M, Bespyatykh J, Goncharenko A, Shumkov M. The Benefits of Toxicity: M. smegmatis VapBC TA Module Is Induced by Tetracycline Exposure and Promotes Survival. Microorganisms 2023; 11:2863. [PMID: 38138007 PMCID: PMC10745673 DOI: 10.3390/microorganisms11122863] [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: 10/01/2023] [Revised: 11/15/2023] [Accepted: 11/22/2023] [Indexed: 12/24/2023] Open
Abstract
Toxin-antitoxin (TA) systems are widely present in bacterial genomes. Mycolicibacterium smegmatis, a common model organism for studying Mycobacterium tuberculosis physiology, has eight TA loci, including mazEF and vapBC. This study aims to investigate the physiological significance of these TA systems. Proteomic profiling was conducted on a culture overexpressing the VapC toxin, and the involvement of VapC in M. smegmatis stress responses to heat shock and antibiotic treatment was examined. While deciphering the underlying mechanisms of the altered stress resistance, we assessed the antibiotic susceptibility of vapBC, mazEF, and double vapBC-mazEF deletion mutants. Additionally, the mRNA levels of vapC and mazF were measured following tetracycline supplementation. The results reveal changes in the abundance of metabolic enzymes and stress response proteins associated with VapC overexpression. This activation of the general stress response leads to reduced thermosensitivity in M. smegmatis, but does not affect susceptibility to ciprofloxacin and isoniazid. Under tetracycline treatment, both vapC and mazF expression levels are increased, and the fate of the cell depends on the interaction between the corresponding TA systems.
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Affiliation(s)
- Mikhail Zamakhaev
- Federal Research Center Fundamentals of Biotechnology of the Russian Academy of Sciences, 33, bld. 2 Leninsky Ave., 119071 Moscow, Russia; (A.G.); (M.S.)
| | - Julia Bespyatykh
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, 1A Malaya Pirogovskaya St., 119435 Moscow, Russia;
- Expertise Department in Anti-Doping and Drug Control, Mendeleev University of Chemical Technology of Russia, 9, Miusskaya Sq., 125047 Moscow, Russia
| | - Anna Goncharenko
- Federal Research Center Fundamentals of Biotechnology of the Russian Academy of Sciences, 33, bld. 2 Leninsky Ave., 119071 Moscow, Russia; (A.G.); (M.S.)
| | - Mikhail Shumkov
- Federal Research Center Fundamentals of Biotechnology of the Russian Academy of Sciences, 33, bld. 2 Leninsky Ave., 119071 Moscow, Russia; (A.G.); (M.S.)
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Chen X, Hu A, Zou Q, Luo S, Wu H, Yan C, Liu T, He D, Li X, Cheng G. The Mesorhizobium huakuii transcriptional regulator AbiEi plays a critical role in nodulation and is important for bacterial stress response. BMC Microbiol 2021; 21:245. [PMID: 34511061 PMCID: PMC8436566 DOI: 10.1186/s12866-021-02304-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/28/2021] [Indexed: 11/16/2022] Open
Abstract
Background Bacterial abortive infection (Abi) systems are type IV toxin–antitoxin (TA) system, which could elicit programmed cell death and constitute a native survival strategy of pathogenic bacteria under various stress conditions. However, no rhizobial AbiE family TA system has been reported so far. Here, a M. huakuii AbiE TA system was identified and characterized. Results A mutation in M. huakuii abiEi gene, encoding an adjacent GntR-type transcriptional regulator, was generated by homologous recombination. The abiEi mutant strain grew less well in rich TY medium, and displayed increased antioxidative capacity and enhanced gentamicin resistance, indicating the abiEi operon was negatively regulated by the antitoxin AbiEi in response to the oxidative stress and a particular antibiotic. The mRNA expression of abiEi gene was significantly up-regulated during Astragalus sinicus nodule development. The abiEi mutant was severely impaired in its competitive ability in rhizosphere colonization, and was defective in nodulation with 97% reduction in nitrogen-fixing capacity. The mutant infected nodule cells contained vacuolation and a small number of abnormal bacteroids with senescence character. RNA-seq experiment revealed it had 5 up-regulated and 111 down-regulated genes relative to wild type. Of these down-regulated genes, 21 are related to symbiosis nitrogen fixation and nitrogen mechanism, 16 are involved in the electron transport chain and antioxidant responses, and 12 belong to type VI secretion system (T6SS). Conclusions M. huakuii AbiEi behaves as a key transcriptional regulator mediating root nodule symbiosis. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02304-0.
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Affiliation(s)
- Xiaohong Chen
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, 430074, Hubei, China
| | - Aiqi Hu
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, 430074, Hubei, China
| | - Qian Zou
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, 430074, Hubei, China
| | - Sha Luo
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, 430074, Hubei, China
| | - Hetao Wu
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, 430074, Hubei, China
| | - Chunlan Yan
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, 430074, Hubei, China
| | - Tao Liu
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, 430074, Hubei, China
| | - Donglan He
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, 430074, Hubei, China
| | - Xiaohua Li
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, 430074, Hubei, China
| | - Guojun Cheng
- Hubei Provincial Engineering and Technology Research Center for Resources and Utilization of Microbiology, College of Life Sciences, South-Central University for Nationalities, Wuhan, 430074, Hubei, China.
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Boivin S, Mahé F, Debellé F, Pervent M, Tancelin M, Tauzin M, Wielbo J, Mazurier S, Young P, Lepetit M. Genetic Variation in Host-Specific Competitiveness of the Symbiont Rhizobium leguminosarum Symbiovar viciae. FRONTIERS IN PLANT SCIENCE 2021; 12:719987. [PMID: 34567032 PMCID: PMC8457355 DOI: 10.3389/fpls.2021.719987] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 07/29/2021] [Indexed: 05/25/2023]
Abstract
Legumes of the Fabeae tribe form nitrogen-fixing root nodules resulting from symbiotic interaction with the soil bacteria Rhizobium leguminosarum symbiovar viciae (Rlv). These bacteria are all potential symbionts of the Fabeae hosts but display variable partner choice when co-inoculated in mixture. Because partner choice and symbiotic nitrogen fixation mostly behave as genetically independent traits, the efficiency of symbiosis is often suboptimal when Fabeae legumes are exposed to natural Rlv populations present in soil. A core collection of 32 Rlv bacteria was constituted based on the genomic comparison of a collection of 121 genome sequences, representative of known worldwide diversity of Rlv. A variable part of the nodD gene sequence was used as a DNA barcode to discriminate and quantify each of the 32 bacteria in mixture. This core collection was co-inoculated on a panel of nine genetically diverse Pisum sativum, Vicia faba, and Lens culinaris genotypes. We estimated the relative Early Partner Choice (EPC) of the bacteria with the Fabeae hosts by DNA metabarcoding on the nodulated root systems. Comparative genomic analyses within the bacterial core collection identified molecular markers associated with host-dependent symbiotic partner choice. The results revealed emergent properties of rhizobial populations. They pave the way to identify genes related to important symbiotic traits operating at this level.
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Affiliation(s)
- Stéphane Boivin
- Laboratoire des Symbioses Tropicales et Méditerranéennes, INRAE, IRD, CIRAD, Montpellier SupAgro, University of Montpellier, Montpellier, France
| | - Frederic Mahé
- Biologie et Génétique des Interactions Plante-Parasite, CIRAD, INRAE, Montpellier SupAgro, University of Montpellier, Montpellier, France
| | - Frédéric Debellé
- Laboratoire des Interactions Plantes-Microorganismes, INRAE, CNRS, University of Toulouse, Castanet-Tolosan, France
| | - Marjorie Pervent
- Laboratoire des Symbioses Tropicales et Méditerranéennes, INRAE, IRD, CIRAD, Montpellier SupAgro, University of Montpellier, Montpellier, France
| | - Mathilde Tancelin
- Laboratoire des Symbioses Tropicales et Méditerranéennes, INRAE, IRD, CIRAD, Montpellier SupAgro, University of Montpellier, Montpellier, France
| | - Marc Tauzin
- Laboratoire des Symbioses Tropicales et Méditerranéennes, INRAE, IRD, CIRAD, Montpellier SupAgro, University of Montpellier, Montpellier, France
| | - Jerzy Wielbo
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Lublin, Poland
| | - Sylvie Mazurier
- Agroecology, AgroSup Dijon, INRAE, University Burgundy Franche-Comté, Dijon, France
| | - Peter Young
- Department of Biology, University of York, York, United Kingdom
| | - Marc Lepetit
- Laboratoire des Symbioses Tropicales et Méditerranéennes, INRAE, IRD, CIRAD, Montpellier SupAgro, University of Montpellier, Montpellier, France
- Institut Sophia Agrobiotech, INRAE, CNRS, Côte d’Azur University, Sophia-Antipolis, France
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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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Endosymbionts of Metazoans Dwelling in the PACManus Hydrothermal Vent: Diversity and Potential Adaptive Features Revealed by Genome Analysis. Appl Environ Microbiol 2020; 86:AEM.00815-20. [PMID: 32859597 PMCID: PMC7580541 DOI: 10.1128/aem.00815-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 08/22/2020] [Indexed: 12/04/2022] Open
Abstract
Deep-sea hydrothermal vents are dominated by several invertebrate species. The establishment of symbiosis has long been thought to be the key to successful colonization by these sedentary species in such harsh environments. However, the relationships between symbiotic bacteria and their hosts and their role in environmental adaptations generally remain unclear. In this paper, we show that the distribution of three host species showed characteristic niche partitioning in the Manus Basin, giving us the opportunity to understand how they adapt to their particular habitats. This study also revealed three novel genomes of symbionts from the snails of A. boucheti. Combined with a data set on other ectosymbiont and free-living bacteria, genome comparisons for the snail endosymbionts pointed to several genetic traits that may have contributed to the lifestyle shift of Epsilonproteobacteria into the epithelial cells. These findings could increase our understanding of invertebrate-endosymbiont relationships in deep-sea ecosystems. Deep-sea hydrothermal vent communities are dominated by invertebrates, namely, bathymodiolin mussels, siboglinid tubeworms, and provannid snails. Symbiosis is considered key to successful colonization by these sedentary species in such extreme environments. In the PACManus vent fields, snails, tubeworms, and mussels each colonized a niche with distinct geochemical characteristics. To better understand the metabolic potentials and genomic features contributing to host-environment adaptation, we compared the genomes of the symbionts of Bathymodiolus manusensis, Arcovestia ivanovi, and Alviniconcha boucheti sampled at PACManus, and we discuss their environmentally adaptive features. We found that B. manusensis and A. ivanovi are colonized by Gammaproteobacteria from distinct clades, whereas endosymbionts of B. manusensis feature high intraspecific heterogeneity with differing metabolic potentials. A. boucheti harbored three novel Epsilonproteobacteria symbionts, suggesting potential species-level diversity of snail symbionts. Genome comparisons revealed that the relative abundance of gene families related to low-pH homeostasis, metal resistance, oxidative stress resistance, environmental sensing/responses, and chemotaxis and motility was the highest in A. ivanovi’s symbiont, followed by symbionts of the vent-mouth-dwelling snail A. boucheti, and was relatively low in the symbiont of the vent-periphery-dwelling mussel B. manusensis, which is consistent with their environmental adaptations and host-symbiont interactions. Gene families classified as encoding host interaction/attachment, virulence factors/toxins, and eukaryotic-like proteins were most abundant in symbionts of mussels and least abundant in those of snails, indicating that these symbionts may differ in their host colonization strategies. Comparison of Epsilonproteobacteria symbionts to nonsymbionts demonstrated that the expanded gene families in symbionts were related to vitamin B12 synthesis, toxin-antitoxin systems, methylation, and lipopolysaccharide biosynthesis, suggesting that these are vital to symbiont establishment and development in Epsilonproteobacteria. IMPORTANCE Deep-sea hydrothermal vents are dominated by several invertebrate species. The establishment of symbiosis has long been thought to be the key to successful colonization by these sedentary species in such harsh environments. However, the relationships between symbiotic bacteria and their hosts and their role in environmental adaptations generally remain unclear. In this paper, we show that the distribution of three host species showed characteristic niche partitioning in the Manus Basin, giving us the opportunity to understand how they adapt to their particular habitats. This study also revealed three novel genomes of symbionts from the snails of A. boucheti. Combined with a data set on other ectosymbiont and free-living bacteria, genome comparisons for the snail endosymbionts pointed to several genetic traits that may have contributed to the lifestyle shift of Epsilonproteobacteria into the epithelial cells. These findings could increase our understanding of invertebrate-endosymbiont relationships in deep-sea ecosystems.
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Boivin S, Ait Lahmidi N, Sherlock D, Bonhomme M, Dijon D, Heulin‐Gotty K, Le‐Queré A, Pervent M, Tauzin M, Carlsson G, Jensen E, Journet E, Lopez‐Bellido R, Seidenglanz M, Marinkovic J, Colella S, Brunel B, Young P, Lepetit M. Host-specific competitiveness to form nodules in Rhizobium leguminosarum symbiovar viciae. THE NEW PHYTOLOGIST 2020; 226:555-568. [PMID: 31873949 PMCID: PMC7687279 DOI: 10.1111/nph.16392] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 12/09/2019] [Indexed: 05/07/2023]
Abstract
Fabeae legumes such as pea and faba bean form symbiotic nodules with a large diversity of soil Rhizobium leguminosarum symbiovar viciae (Rlv) bacteria. However, bacteria competitive to form root nodules (CFN) are generally not the most efficient to fix dinitrogen, resulting in a decrease in legume crop yields. Here, we investigate differential selection by host plants on the diversity of Rlv. A large collection of Rlv was collected by nodule trapping with pea and faba bean from soils at five European sites. Representative genomes were sequenced. In parallel, diversity and abundance of Rlv were estimated directly in these soils using metabarcoding. The CFN of isolates was measured with both legume hosts. Pea/faba bean CFN were associated to Rlv genomic regions. Variations of bacterial pea and/or faba bean CFN explained the differential abundance of Rlv genotypes in pea and faba bean nodules. No evidence was found for genetic association between CFN and variations in the core genome, but variations in specific regions of the nod locus, as well as in other plasmid loci, were associated with differences in CFN. These findings shed light on the genetic control of CFN in Rlv and emphasise the importance of host plants in controlling Rhizobium diversity.
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Affiliation(s)
- Stéphane Boivin
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM) INRAE, IRD, CIRADUniversity of MontpellierMontpellier SupAgro34398Montpellier cedex 5France
| | - Nassima Ait Lahmidi
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM) INRAE, IRD, CIRADUniversity of MontpellierMontpellier SupAgro34398Montpellier cedex 5France
| | | | - Maxime Bonhomme
- Laboratoire de Recherche en Sciences Végétales, CNRS, UPSUniversité de Toulouse31326Castanet‐TolosanFrance
| | - Doriane Dijon
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM) INRAE, IRD, CIRADUniversity of MontpellierMontpellier SupAgro34398Montpellier cedex 5France
| | - Karine Heulin‐Gotty
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM) INRAE, IRD, CIRADUniversity of MontpellierMontpellier SupAgro34398Montpellier cedex 5France
| | - Antoine Le‐Queré
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM) INRAE, IRD, CIRADUniversity of MontpellierMontpellier SupAgro34398Montpellier cedex 5France
| | - Marjorie Pervent
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM) INRAE, IRD, CIRADUniversity of MontpellierMontpellier SupAgro34398Montpellier cedex 5France
| | - Marc Tauzin
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM) INRAE, IRD, CIRADUniversity of MontpellierMontpellier SupAgro34398Montpellier cedex 5France
| | - Georg Carlsson
- Department of Biosystems and TechnologySwedish University of Agricultural SciencesSE‐230 53AlnarpSweden
| | - Erik Jensen
- Department of Biosystems and TechnologySwedish University of Agricultural SciencesSE‐230 53AlnarpSweden
| | - Etienne‐Pascal Journet
- AGroécologie, Innovation et teRritoires (AGIR) INRAEENSAT31326Castanet‐TolosanFrance
- Laboratoire des Interactions Plantes MicrorganismesUniversité de Toulouse, INRAE, CNRS31326Castanet‐TolosanFrance
| | - Raphael Lopez‐Bellido
- Departamento de Ciencias y Recursos Agrícolas y ForestalesUniversity of Córdoba14071CórdobaSpain
| | | | | | - Stefano Colella
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM) INRAE, IRD, CIRADUniversity of MontpellierMontpellier SupAgro34398Montpellier cedex 5France
| | - Brigitte Brunel
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM) INRAE, IRD, CIRADUniversity of MontpellierMontpellier SupAgro34398Montpellier cedex 5France
| | - Peter Young
- Department of BiologyUniversity of YorkYorkYO10 5DDUK
| | - Marc Lepetit
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM) INRAE, IRD, CIRADUniversity of MontpellierMontpellier SupAgro34398Montpellier cedex 5France
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Syska C, Brouquisse R, Alloing G, Pauly N, Frendo P, Bosseno M, Dupont L, Boscari A. Molecular Weapons Contribute to Intracellular Rhizobia Accommodation Within Legume Host Cell. FRONTIERS IN PLANT SCIENCE 2019; 10:1496. [PMID: 31850013 PMCID: PMC6902015 DOI: 10.3389/fpls.2019.01496] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 10/28/2019] [Indexed: 06/10/2023]
Abstract
The interaction between legumes and bacteria of rhizobia type results in a beneficial symbiotic relationship characterized by the formation of new root organs, called nodules. Within these nodules the bacteria, released in plant cells, differentiate into bacteroids and fix atmospheric nitrogen through the nitrogenase activity. This mutualistic interaction has evolved sophisticated signaling networks to allow rhizobia entry, colonization, bacteroid differentiation and persistence in nodules. Nodule cysteine rich (NCR) peptides, reactive oxygen species (ROS), reactive nitrogen species (RNS), and toxin-antitoxin (TA) modules produced by the host plants or bacterial microsymbionts have a major role in the control of the symbiotic interaction. These molecules described as weapons in pathogenic interactions have evolved to participate to the intracellular bacteroid accommodation by escaping control of plant innate immunity and adapt the functioning of the nitrogen-fixation to environmental signalling cues.
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Affiliation(s)
- Camille Syska
- Université Côte d’Azur, INRA, CNRS, ISA, Sophia Antipolis, France
| | | | | | - Nicolas Pauly
- Laboratoire des Interactions Plantes-Microorganismes, INRA, CNRS, Université de Toulouse, Castanet-Tolosan, France
| | - Pierre Frendo
- Université Côte d’Azur, INRA, CNRS, ISA, Sophia Antipolis, France
| | - Marc Bosseno
- Université Côte d’Azur, INRA, CNRS, ISA, Sophia Antipolis, France
| | - Laurence Dupont
- Université Côte d’Azur, INRA, CNRS, ISA, Sophia Antipolis, France
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Thomet M, Trautwetter A, Ermel G, Blanco C. Characterization of HicAB toxin-antitoxin module of Sinorhizobium meliloti. BMC Microbiol 2019; 19:10. [PMID: 30630415 PMCID: PMC6327479 DOI: 10.1186/s12866-018-1382-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 12/26/2018] [Indexed: 02/06/2023] Open
Abstract
Background Toxin-antitoxin (TA) systems are little genetic units generally composed of two genes encoding antitoxin and toxin. These systems are known to be involved in many functions that can lead to growth arrest and cell death. Among the different types of TA systems, the type II gathers together systems where the antitoxin directly binds and inhibits the toxin. Among these type II TA systems, the HicAB module is widely distributed in free-living Bacteria and Archaea and the toxin HicA functions via RNA binding and cleavage. The genome of the symbiotic Sinorhizobium meliloti encodes numerous TA systems and only a few of them are functional. Among the predicted TA systems, there is one homologous to HicAB modules. Results In this study, we characterize the HicAB toxin-antitoxin module of S. meliloti. The production of the HicA of S. meliloti in Escherichia coli cells abolishes growth and decreases cell viability. We show that expression of the HicB of S. meliloti counteracts HicA toxicity. The results of double hybrid assays and co-purification experiments allow demonstrating the interaction of HicB with the toxin HicA. Purified HicA, but not HicAB complex, is able to degrade ribosomal RNA in vitro. The analysis of separated domains of HicB protein permits us to define the antitoxin activity and the operator-binding domain. Conclusions This study points out the first characterization of the HicAB system of the symbiotic S. meliloti whereas HicA is a toxin with ribonuclease activity and HicB has two domains: the COOH-terminal one that binds the operator and the NH2-terminal one that inhibits the toxin. Electronic supplementary material The online version of this article (10.1186/s12866-018-1382-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Manon Thomet
- Ribosome, bacteria and stress Team, Univ. Rennes, CNRS, Institut de Génétique et de Développement de Rennes (IGDR), UMR6290, F35000, Rennes, France
| | - Annie Trautwetter
- Ribosome, bacteria and stress Team, Univ. Rennes, CNRS, Institut de Génétique et de Développement de Rennes (IGDR), UMR6290, F35000, Rennes, France
| | - Gwennola Ermel
- Ribosome, bacteria and stress Team, Univ. Rennes, CNRS, Institut de Génétique et de Développement de Rennes (IGDR), UMR6290, F35000, Rennes, France.
| | - Carlos Blanco
- Ribosome, bacteria and stress Team, Univ. Rennes, CNRS, Institut de Génétique et de Développement de Rennes (IGDR), UMR6290, F35000, Rennes, France
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Salvioli di Fossalunga A, Lipuma J, Venice F, Dupont L, Bonfante P. The endobacterium of an arbuscular mycorrhizal fungus modulates the expression of its toxin-antitoxin systems during the life cycle of its host. ISME JOURNAL 2017; 11:2394-2398. [PMID: 28548657 DOI: 10.1038/ismej.2017.84] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 04/11/2017] [Accepted: 04/19/2017] [Indexed: 02/06/2023]
Abstract
Arbuscular mycorrhizal fungi (AMF) are widespread root symbionts that perform important ecological services, such as improving plant nutrient and water acquisition. Some AMF from the Gigasporaceae family host a population of endobacteria, Candidatus Glomeribacter gigasporarum (Cagg). The analysis of the Cagg genome identified six putative toxin-antitoxin modules (TAs), consisting of pairs of stable toxins and unstable antitoxins that affect diverse physiological functions. Sequence analysis suggested that these TA modules were acquired by horizontal transfer. Gene expression patterns of two TAs (yoeB/yefM and chpB/chpS) changed during the fungal life cycle, with the expression during the pre-symbiotic phase higher than during the symbiosis with the plant host. The heterologous expression in Escherichia coli demonstrated the functionality only for the YoeB-YefM pair. On the basis of these observations, we speculate that TA modules might help Cagg adapt to its intracellular habitat, coordinating its proliferation with the physiological state of the AMF host.
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Affiliation(s)
| | - Justine Lipuma
- Institut Sophia Agrobiotech (ISA), INRA UMR 1355, CNRS UMR 7254, Université de Nice Sophia Antipolis, Sophia Antipolis, France
| | - Francesco Venice
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
| | - Laurence Dupont
- Institut Sophia Agrobiotech (ISA), INRA UMR 1355, CNRS UMR 7254, Université de Nice Sophia Antipolis, Sophia Antipolis, France
| | - Paola Bonfante
- Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
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Alunni B, Gourion B. Terminal bacteroid differentiation in the legume-rhizobium symbiosis: nodule-specific cysteine-rich peptides and beyond. THE NEW PHYTOLOGIST 2016; 211:411-7. [PMID: 27241115 DOI: 10.1111/nph.14025] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 04/14/2016] [Indexed: 05/06/2023]
Abstract
Contents 411 I. 411 II. 412 III. 412 IV. 413 V. 414 VI. 414 VII. 415 VIII. 415 416 References 416 SUMMARY: Terminal bacteroid differentiation (TBD) is a remarkable case of bacterial cell differentiation that occurs after rhizobia are released intracellularly within plant cells of symbiotic legume organs called nodules. The hallmarks of TBD are cell enlargement, genome amplification and membrane permeabilization. This plant-driven process is governed by a large family of bacteroid-targeted nodule-specific cysteine-rich (NCR) peptides that were until recently thought to be restricted to a specific lineage of the legume family, including the model plant Medicago truncatula. Recently, new plant and bacterial factors involved in TBD have been identified, challenging our view of this phenomenon at mechanistic and evolutionary levels. Here, we review the recent literature and discuss emerging questions about the mechanisms and the role(s) of TBD.
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Affiliation(s)
- Benoît Alunni
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, Gif-sur-Yvette, France
| | - Benjamin Gourion
- LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France
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