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Moréra S, Vigouroux A, Aumont-Nicaise M, Ahmar M, Meyer T, El Sahili A, Deicsics G, González-Mula A, Li S, Doré J, Sirigu S, Legrand P, Penot C, André F, Faure D, Soulère L, Queneau Y, Vial L. A highly conserved ligand-binding site for AccA transporters of antibiotic and quorum-sensing regulator in Agrobacterium leads to a different specificity. Biochem J 2024; 481:93-117. [PMID: 38058289 DOI: 10.1042/bcj20230273] [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: 06/29/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 12/08/2023]
Abstract
Plants genetically modified by the pathogenic Agrobacterium strain C58 synthesize agrocinopines A and B, whereas those modified by the pathogenic strain Bo542 produce agrocinopines C and D. The four agrocinopines (A, B, C and D) serve as nutrients by agrobacteria and signaling molecule for the dissemination of virulence genes. They share the uncommon pyranose-2-phosphate motif, represented by the l-arabinopyranose moiety in agrocinopines A/B and the d-glucopyranose moiety in agrocinopines C/D, also found in the antibiotic agrocin 84. They are imported into agrobacterial cytoplasm via the Acc transport system, including the solute-binding protein AccA coupled to an ABC transporter. We have previously shown that unexpectedly, AccA from strain C58 (AccAC58) recognizes the pyranose-2-phosphate motif present in all four agrocinopines and agrocin 84, meaning that strain C58 is able to import agrocinopines C/D, originating from the competitor strain Bo542. Here, using agrocinopine derivatives and combining crystallography, affinity and stability measurements, modeling, molecular dynamics, in vitro and vivo assays, we show that AccABo542 and AccAC58 behave differently despite 75% sequence identity and a nearly identical ligand binding site. Indeed, strain Bo542 imports only compounds containing the d-glucopyranose-2-phosphate moiety, and with a lower affinity compared with strain C58. This difference in import efficiency makes C58 more competitive than Bo542 in culture media. We can now explain why Agrobacterium/Allorhizobium vitis strain S4 is insensitive to agrocin 84, although its genome contains a conserved Acc transport system. Overall, our work highlights AccA proteins as a case study, for which stability and dynamics drive specificity.
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Affiliation(s)
- Solange Moréra
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Armelle Vigouroux
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Magali Aumont-Nicaise
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Mohammed Ahmar
- Univ Lyon, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, CNRS, Université Lyon 1, INSA Lyon, CPE Lyon, ICBMS, UMR 5246; Université Claude Bernard, Bâtiment Lederer, 69622 Villeurbanne Cedex, France
| | - Thibault Meyer
- UMR Ecologie Microbienne, CNRS, INRAE, VetAgro Sup, UCBL, Université de Lyon, Villeurbanne, F-69622 Lyon, France
| | - Abbas El Sahili
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Grégory Deicsics
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Almudena González-Mula
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Sizhe Li
- Univ Lyon, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, CNRS, Université Lyon 1, INSA Lyon, CPE Lyon, ICBMS, UMR 5246; Université Claude Bernard, Bâtiment Lederer, 69622 Villeurbanne Cedex, France
| | - Jeanne Doré
- UMR Ecologie Microbienne, CNRS, INRAE, VetAgro Sup, UCBL, Université de Lyon, Villeurbanne, F-69622 Lyon, France
| | - Serena Sirigu
- Synchrotron SOLEIL, HelioBio Group, 91190 Saint-Aubin, France
| | - Pierre Legrand
- Synchrotron SOLEIL, HelioBio Group, 91190 Saint-Aubin, France
| | - Camille Penot
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - François André
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Denis Faure
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Laurent Soulère
- Univ Lyon, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, CNRS, Université Lyon 1, INSA Lyon, CPE Lyon, ICBMS, UMR 5246; Université Claude Bernard, Bâtiment Lederer, 69622 Villeurbanne Cedex, France
| | - Yves Queneau
- Univ Lyon, Institut de Chimie et Biochimie Moléculaires et Supramoléculaires, CNRS, Université Lyon 1, INSA Lyon, CPE Lyon, ICBMS, UMR 5246; Université Claude Bernard, Bâtiment Lederer, 69622 Villeurbanne Cedex, France
| | - Ludovic Vial
- UMR Ecologie Microbienne, CNRS, INRAE, VetAgro Sup, UCBL, Université de Lyon, Villeurbanne, F-69622 Lyon, France
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Buyel JF. Product safety aspects of plant molecular farming. Front Bioeng Biotechnol 2023; 11:1238917. [PMID: 37614627 PMCID: PMC10442644 DOI: 10.3389/fbioe.2023.1238917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 07/31/2023] [Indexed: 08/25/2023] Open
Abstract
Plant molecular farming (PMF) has been promoted since the 1990s as a rapid, cost-effective and (most of all) safe alternative to the cultivation of bacteria or animal cells for the production of biopharmaceutical proteins. Numerous plant species have been investigated for the production of a broad range of protein-based drug candidates. The inherent safety of these products is frequently highlighted as an advantage of PMF because plant viruses do not replicate in humans and vice versa. However, a more nuanced analysis of this principle is required when considering other pathogens because toxic compounds pose a risk even in the absence of replication. Similarly, it is necessary to assess the risks associated with the host system (e.g., the presence of toxic secondary metabolites) and the production approach (e.g., transient expression based on bacterial infiltration substantially increases the endotoxin load). This review considers the most relevant host systems in terms of their toxicity profile, including the presence of secondary metabolites, and the risks arising from the persistence of these substances after downstream processing and product purification. Similarly, we discuss a range of plant pathogens and disease vectors that can influence product safety, for example, due to the release of toxins. The ability of downstream unit operations to remove contaminants and process-related toxic impurities such as endotoxins is also addressed. This overview of plant-based production, focusing on product safety aspects, provides recommendations that will allow stakeholders to choose the most appropriate strategies for process development.
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Affiliation(s)
- J. F. Buyel
- Department of Biotechnology (DBT), Institute of Bioprocess Science and Engineering (IBSE), University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
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Du Y, Zou J, Yin Z, Chen T. Pan-Chromosome and Comparative Analysis of Agrobacterium fabrum Reveal Important Traits Concerning the Genetic Diversity, Evolutionary Dynamics, and Niche Adaptation of the Species. Microbiol Spectr 2023; 11:e0292422. [PMID: 36853054 PMCID: PMC10100860 DOI: 10.1128/spectrum.02924-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 02/14/2023] [Indexed: 03/01/2023] Open
Abstract
Agrobacterium fabrum has been critical for the development of plant genetic engineering and agricultural biotechnology due to its ability to transform eukaryotic cells. However, the gene composition, evolutionary dynamics, and niche adaptation of this species is still unknown. Therefore, we established a comparative genomic analysis based on a pan-chromosome data set to evaluate the genetic diversity of A. fabrum. Here, 25 A. fabrum genomes were selected for analysis by core genome phylogeny combined with the average nucleotide identity (ANI), amino acid identity (AAI), and in silico DNA-DNA hybridization (DDH) values. An open pan-genome of A. fabrum exhibits genetic diversity with variable accessorial genes as evidenced by a consensus pan-genome of 12 representative genomes. The genomic plasticity of A. fabrum is apparent in its putative sequences for mobile genetic elements (MGEs), limited horizontal gene transfer barriers, and potentially horizontally transferred genes. The evolutionary constraints and functional enrichment in the pan-chromosome were measured by the Clusters of Orthologous Groups (COG) categories using eggNOG-mapper software, and the nonsynonymous/synonymous rate ratio (dN/dS) was determined using HYPHY software. Comparative analysis revealed significant differences in the functional enrichment and the degree of purifying selection between the core genome and non-core genome. We demonstrate that the core gene families undergo stronger purifying selection but have a significant bias to contain one or more positively selected sites. Furthermore, although they shared similar genetic diversity, we observed significant differences between chromosome 1 (Chr I) and the chromid in their functional features and evolutionary constraints. We demonstrate that putative genetic elements responsible for plant infection, ecological adaptation, and speciation represent the core genome, highlighting their importance in the adaptation of A. fabrum to plant-related niches. Our pan-chromosome analysis of A. fabrum provides comprehensive insights into the genetic properties, evolutionary patterns, and niche adaptation of the species. IMPORTANCE Agrobacterium spp. live in diverse plant-associated niches such as soil, the rhizosphere, and vegetation, which are challenged by multiple stressors such as diverse energy sources, plant defenses, and microbial competition. They have evolved the ability to utilize diverse resources, escape plant defenses, and defeat competitors. However, the underlying genetic diversity and evolutionary dynamics of Agrobacterium spp. remain unexplored. We examined the phylogeny and pan-genome of A. fabrum to define intraspecies evolutionary relationships. Our results indicate an open pan-genome and numerous MGEs and horizontally transferred genes among A. fabrum genomes, reflecting the flexibility of the chromosomes and the potential for genetic exchange. Furthermore, we observed significant differences in the functional features and evolutionary constraints between the core and accessory genomes and between Chr I and the chromid, respectively.
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Affiliation(s)
- Yuhui Du
- MOE International Joint Research Laboratory on Synthetic Biology and Medicines, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, People’s Republic of China
| | - Jinrong Zou
- MOE International Joint Research Laboratory on Synthetic Biology and Medicines, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, People’s Republic of China
| | - Zhiqiu Yin
- Clinical Laboratory Department, Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, People’s Republic of China
- National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Tai’an, People’s Republic of China
| | - Tingjian Chen
- MOE International Joint Research Laboratory on Synthetic Biology and Medicines, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, People’s Republic of China
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Induction of AmpC-Mediated β-Lactam Resistance Requires a Single Lytic Transglycosylase in Agrobacterium tumefaciens. Appl Environ Microbiol 2022; 88:e0033322. [PMID: 35638841 PMCID: PMC9238390 DOI: 10.1128/aem.00333-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The remarkable ability of Agrobacterium tumefaciens to transfer DNA to plant cells has allowed the generation of important transgenic crops. One challenge of A. tumefaciens-mediated transformation is eliminating the bacteria after plant transformation to prevent detrimental effects to plants and the release of engineered bacteria to the environment. Here, we use a reverse-genetics approach to identify genes involved in ampicillin resistance, with the goal of utilizing these antibiotic-sensitive strains for plant transformations. We show that treating A. tumefaciens C58 with ampicillin led to increased β-lactamase production, a response dependent on the broad-spectrum β-lactamase AmpC and its transcription factor, AmpR. Loss of the putative ampD orthologue atu2113 led to constitutive production of AmpC-dependent β-lactamase activity and ampicillin resistance. Finally, one cell wall remodeling enzyme, MltB3, was necessary for the AmpC-dependent β-lactamase activity, and its loss elicited ampicillin and carbenicillin sensitivity in the A. tumefaciens C58 and GV3101 strains. Furthermore, GV3101 ΔmltB3 transforms plants with efficiency comparable to that of the wild type but can be cleared with sublethal concentrations of ampicillin. The functional characterization of the genes involved in the inducible ampicillin resistance pathway of A. tumefaciens constitutes a major step forward in efforts to reduce the intrinsic antibiotic resistance of this bacterium. IMPORTANCE Agrobacterium tumefaciens, a significant biotechnological tool for production of transgenic plant lines, is highly resistant to a wide variety of antibiotics, posing challenges for various applications. One challenge is the efficient elimination of A. tumefaciens from transformed plant tissue without using levels of antibiotics that are toxic to the plants. Here, we present the functional characterization of genes involved in β-lactam resistance in A. tumefaciens. Knowledge about proteins that promote or inhibit β-lactam resistance will enable the development of strains to improve the efficiency of Agrobacterium-mediated plant genetic transformations. Effective removal of Agrobacterium from transformed plant tissue has the potential to maximize crop yield and food production, improving the outlook for global food security.
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Phenotypic and Molecular-Phylogenetic Analyses Reveal Distinct Features of Crown Gall-Associated Xanthomonas Strains. Microbiol Spectr 2022; 10:e0057721. [PMID: 35107322 PMCID: PMC8809331 DOI: 10.1128/spectrum.00577-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In summer 2019, widespread occurrence of crown gall disease caused by Agrobacterium spp. was observed on commercially grown ornamental plants in southern Iran. Beside agrobacteria, pale yellow-pigmented Gram-negative strains resembling the members of Xanthomonas were also associated with crown gall tissues on weeping fig (Ficus benjamina) and Amaranthus sp. plants. The purpose of the present study was to characterize the crown gall-associated Xanthomonas strains using plant inoculation assays, molecular-phylogenetic analyses, and comparative genomics approaches. Pathogenicity tests showed that the Xanthomonas strains did not induce disease symptoms on their host of isolation. However, the strains induced hypersensitive reaction on tobacco, geranium, melon, squash, and tomato leaves via leaf infiltration. Multilocus sequence analysis suggested that the strains belong to clade IA of Xanthomonas, phylogenetically close to Xanthomonas translucens, X. theicola, and X. hyacinthi. Average nucleotide identity and digital DNA-DNA hybridization values between the whole-genome sequences of the strains isolated in this study and reference Xanthomonas strains are far below the accepted thresholds for the definition of prokaryotic species, signifying that these strains could be defined as two new species within clade IA of Xanthomonas. Comparative genomics showed that the strains isolated from crown gall tissues are genetically distinct from X. translucens, as almost all the type III secretion system genes and type III effectors are lacking in the former group. The data obtained in this study provide novel insight into the breadth of genetic diversity of crown gall-associated bacteria and pave the way for research on gall-associated Xanthomonas-plant interactions. IMPORTANCE Tumorigenic agrobacteria—members of the bacterial family Rhizobiaceae—cause crown gall and hairy root diseases on a broad range of plant species. These bacteria are responsible for economic losses in nurseries of important fruit trees and ornamental plants. The microclimate of crown gall and their accompanying microorganisms has rarely been studied for the microbial diversity and population dynamics of gall-associated bacteria. Here, we employed a series of biochemical tests, pathogenicity assays, and molecular-phylogenetic analyses, supplemented with comparative genomics, to elucidate the biological features, taxonomic position, and genomic repertories of five crown gall-associated Xanthomonas strains isolated from weeping fig and Amaranthus sp. plants in Iran. The strains investigated in this study induced hypersensitive reactions (HR) on geranium, melon, squash, tobacco, and tomato leaves, while they were nonpathogenic on their host of isolation. Phylogenetic analyses and whole-genome-sequence-based average nucleotide identity (ANI)/digital DNA-DNA hybridization (dDDH) calculations suggested that the Xanthomonas strains isolated from crown gall tissues belong to two taxonomically unique clades closely related to the clade IA species of the genus, i.e., X. translucens, X. hyacinthi, and X. theicola.
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6
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Singh NK, Lavire C, Nesme J, Vial L, Nesme X, Mason CE, Lassalle F, Venkateswaran K. Comparative Genomics of Novel Agrobacterium G3 Strains Isolated From the International Space Station and Description of Agrobacterium tomkonis sp. nov. Front Microbiol 2021; 12:765943. [PMID: 34938279 PMCID: PMC8685578 DOI: 10.3389/fmicb.2021.765943] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 10/12/2021] [Indexed: 12/14/2022] Open
Abstract
Strains of Agrobacterium genomospecies 3 (i.e., genomovar G3 of the Agrobacterium tumefaciens species complex) have been previously isolated from diverse environments, including in association with plant roots, with algae, as part of a lignocellulose degrading community, from a hospital environment, as a human opportunistic pathogen, or as reported in this study, from a surface within the International Space Station. Polyphasic taxonomic methods revealed the relationship of Agrobacterium G3 strains to other Agrobacterium spp., which supports the description of a novel species. The G3 strains tested (n = 9) were phenotypically distinguishable among the strains from other genomospecies of the genus Agrobacterium. Phylogenetic analyses of the 16S rRNA gene, gyrB gene, multi-locus sequence analysis, and 1,089-gene core-genome gene concatenate concur that tested G3 strains belong to the Agrobacterium genus and they form a clade distinct from other validly described Agrobacterium species. The distinctiveness of this clade was confirmed by average nucleotide identity (ANI) and in silico digital DNA-DNA hybridization (dDDH) comparisons between the G3 tested strains and all known Agrobacterium species type strains, since obtained values were considerably below the 95% (ANI) and 70% (dDDH) thresholds used for the species delineation. According to the core-genome phylogeny and ANI comparisons, the closest relatives of G3 strains were Agrobacterium sp. strains UGM030330-04 and K599, members of a novel genomospecies we propose to call genomovar G21. Using this polyphasic approach, we characterized the phenotypic and genotypic synapomorphies of Agrobacterium G3, showing it is a bona fide bacterial species, well separated from previously named Agrobacterium species or other recognized genomic species. We thus propose the name Agrobacterium tomkonis for this species previously referred to as Agrobacterium genomospecies 3. The type strain of A. tomkonis is IIF1SW-B1T (= LMG 32164 = NRRL B-65602). Comparative genomic analysis show A. tomkonis strains have species-specific genes associated with secretion of secondary metabolites, including an exopolysaccharide and putative adhesins and resistance to copper. A. tomkonis specific gene functions notably relate to surface adhesion and could be involved to colonize nutrient-poor and harsh habitats. The A. tomkonis strains from the ISS showed presence of a 40-kbp plasmid and several other potential mobile genetic elements detected that could also be part of conjugative elements or integrated prophages.
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Affiliation(s)
- Nitin K. Singh
- Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
| | - Céline Lavire
- CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, Université de Lyon, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Joseph Nesme
- Section of Microbiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Ludovic Vial
- CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, Université de Lyon, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Xavier Nesme
- CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, Université de Lyon, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Christopher E. Mason
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, United States
| | - Florent Lassalle
- Parasites and Microbes Programme, Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Kasthuri Venkateswaran
- Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States
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Vigouroux A, Meyer T, Naretto A, Legrand P, Aumont-Nicaise M, Di Cicco A, Renoud S, Doré J, Lévy D, Vial L, Lavire C, Moréra S. Characterization of the first tetrameric transcription factor of the GntR superfamily with allosteric regulation from the bacterial pathogen Agrobacterium fabrum. Nucleic Acids Res 2021; 49:529-546. [PMID: 33313837 PMCID: PMC7797058 DOI: 10.1093/nar/gkaa1181] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 11/12/2020] [Accepted: 11/24/2020] [Indexed: 12/12/2022] Open
Abstract
A species-specific region, denoted SpG8-1b allowing hydroxycinnamic acids (HCAs) degradation is important for the transition between the two lifestyles (rhizospheric versus pathogenic) of the plant pathogen Agrobacterium fabrum. Indeed, HCAs can be either used as trophic resources and/or as induced-virulence molecules. The SpG8-1b region is regulated by two transcriptional regulators, namely, HcaR (Atu1422) and Atu1419. In contrast to HcaR, Atu1419 remains so far uncharacterized. The high-resolution crystal structures of two fortuitous citrate complexes, two DNA complexes and the apoform revealed that the tetrameric Atu1419 transcriptional regulator belongs to the VanR group of Pfam PF07729 subfamily of the large GntR superfamily. Until now, GntR regulators were described as dimers. Here, we showed that Atu1419 represses three genes of the HCAs catabolic pathway. We characterized both the effector and DNA binding sites and identified key nucleotides in the target palindrome. From promoter activity measurement using defective gene mutants, structural analysis and gel-shift assays, we propose N5,N10-methylenetetrahydrofolate as the effector molecule, which is not a direct product/substrate of the HCA degradation pathway. The Zn2+ ion present in the effector domain has both a structural and regulatory role. Overall, our work shed light on the allosteric mechanism of transcription employed by this GntR repressor.
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Affiliation(s)
- Armelle Vigouroux
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Thibault Meyer
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Anaïs Naretto
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Pierre Legrand
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, 91192 Gif-sur-Yvette, France
| | - Magali Aumont-Nicaise
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Aurélie Di Cicco
- Sorbonne Université, Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 26 rue d’Ulm, 75005 Paris, France
| | - Sébastien Renoud
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Jeanne Doré
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Daniel Lévy
- Sorbonne Université, Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, 26 rue d’Ulm, 75005 Paris, France
| | - Ludovic Vial
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Céline Lavire
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, VetAgro Sup, UMR Ecologie Microbienne, F-69622 Villeurbanne, France
| | - Solange Moréra
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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Kang B, Maeshige T, Okamoto A, Kataoka Y, Yamamoto S, Rikiishi K, Tani A, Sawada H, Suzuki K. The Presence of the Hairy-Root-Disease-Inducing (Ri) Plasmid in Wheat Endophytic Rhizobia Explains a Pathogen Reservoir Function of Healthy Resistant Plants. Appl Environ Microbiol 2020; 86:e00671-20. [PMID: 32631868 PMCID: PMC7440801 DOI: 10.1128/aem.00671-20] [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: 03/20/2020] [Accepted: 06/23/2020] [Indexed: 11/20/2022] Open
Abstract
A large number of strains in the Rhizobium radiobacter species complex (biovar 1 Agrobacterium) have been known as causative pathogens for crown gall and hairy root diseases. Strains within this complex were also found as endophytes in many plant species with no symptoms. The aim of this study was to reveal the endophyte variation of this complex and how these endophytic strains differ from pathogenic strains. In this study, we devised a simple but effective screening method by exploiting the high resolution power of mass spectrometry. We screened endophyte isolates from young wheat and barley plants, which are resistant to the diseases, and identified seven isolates from wheat as members of the R. radiobacter species complex. Through further analyses, we assigned five strains to the genomovar (genomic group) G1 and two strains to G7 in R. radiobacter Notably, these two genomovar groups harbor many known pathogenic strains. In fact, the two G7 endophyte strains showed pathogenicity on tobacco, as well as the virulence prerequisites, including a 200-kbp Ri plasmid. All five G1 strains possessed a 500-kbp plasmid, which is present in well-known crown gall pathogens. These data strongly suggest that healthy wheat plants are reservoirs for pathogenic strains of R. radiobacterIMPORTANCE Crown gall and hairy root diseases exhibit very wide host-plant ranges that cover gymnosperm and dicot plants. The Rhizobium radiobacter species complex harbors causative agents of the two diseases. Recently, endophyte isolates from many plant species have been assigned to this species complex. We isolated seven endophyte strains belonging to the species complex from wheat plants and revealed their genomovar affiliations and plasmid profile. The significance of this study is the finding of the genomovar correlation between the endophytes and the known pathogens, the presence of a virulence ability in two of the seven endophyte strains, and the high ratio of the pathogenic strains in the endophyte strains. This study therefore provides convincing evidence that could unravel the mechanism that maintains pathogenic agents of this species and sporadically delivers them to susceptible plants.
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Affiliation(s)
- Byoungwoo Kang
- Basic Biology Program, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Taichi Maeshige
- Department of Biological Science, Graduate School of Science, Hiroshima University, Hiroshima, Japan
| | - Aya Okamoto
- Department of Biological Science, Graduate School of Science, Hiroshima University, Hiroshima, Japan
| | - Yui Kataoka
- Department of Biological Science, Graduate School of Science, Hiroshima University, Hiroshima, Japan
| | - Shinji Yamamoto
- Department of Biological Science, Graduate School of Science, Hiroshima University, Hiroshima, Japan
| | - Kazuhide Rikiishi
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, Japan
| | - Akio Tani
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama, Japan
| | - Hiroyuki Sawada
- Genetic Resources Center, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan
| | - Katsunori Suzuki
- Basic Biology Program, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
- Department of Biological Science, Graduate School of Science, Hiroshima University, Hiroshima, Japan
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Binns AN, Zhao J. The MexE/MexF/AmeC Efflux Pump of Agrobacterium tumefaciens and Its Role in Ti Plasmid Virulence Gene Expression. J Bacteriol 2020; 202:e00609-19. [PMID: 32015146 PMCID: PMC7099130 DOI: 10.1128/jb.00609-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 01/25/2020] [Indexed: 12/21/2022] Open
Abstract
Expression of the tumor-inducing (Ti) plasmid virulence genes of Agrobacterium tumefaciens is required for the transfer of DNA from the bacterium into plant cells, ultimately resulting in the initiation of plant tumors. The vir genes are induced as a result of exposure to certain phenol derivatives, monosaccharides, and low pH in the extracellular milieu. The soil, as well as wound sites on a plant-the usual site of the virulence activity of this bacterium-can contain these signals, but vir gene expression in the soil would be a wasteful utilization of energy. This suggests that mechanisms may exist to ensure that vir gene expression occurs only at the higher concentrations of inducers typically found at a plant wound site. In a search for transposon-mediated mutations that affect sensitivity for the virulence gene-inducing activity of the phenol, 3,5-dimethoxy-4-hydroxyacetophenone (acetosyringone [AS]), an RND-type efflux pump homologous to the MexE/MexF/OprN pump of Pseudomonas aeruginosa was identified. Phenotypes of mutants carrying an insertion or deletion of pump components included hypersensitivity to the vir-inducing effects of AS, hypervirulence in the tobacco leaf explant virulence assay, and hypersensitivity to the toxic effects of chloramphenicol. Furthermore, the methoxy substituents on the phenol ring of AS appear to be critical for recognition as a pump substrate. These results support the hypothesis that the regulation of virulence gene expression is integrated with cellular activities that elevate the level of plant-derived inducers required for induction so that this occurs preferentially, if not exclusively, in a plant environment.IMPORTANCE Expression of genes controlling the virulence activities of a bacterial pathogen is expected to occur preferentially at host sites vulnerable to that pathogen. Host-derived molecules that induce such activities in the plant pathogen Agrobacterium tumefaciens are found in the soil, as well as in the plant. Here, we tested the hypothesis that mechanisms exist to suppress the sensitivity of Agrobacterium species to a virulence gene-inducing molecule by selecting for mutant bacteria that are hypersensitive to its inducing activity. The mutant genes identified encode an efflux pump whose proposed activity increases the concentration of the inducer necessary for vir gene expression; this pump is also involved in antibiotic resistance, demonstrating a relationship between cellular defense activities and the control of virulence in Agrobacterium.
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Affiliation(s)
- Andrew N Binns
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jinlei Zhao
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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10
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Import pathways of the mannityl-opines into the bacterial pathogen Agrobacterium tumefaciens: structural, affinity and in vivo approaches. Biochem J 2020; 477:615-628. [PMID: 31922182 DOI: 10.1042/bcj20190886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 01/08/2020] [Accepted: 01/10/2020] [Indexed: 11/17/2022]
Abstract
Agrobacterium tumefaciens pathogens use specific compounds denoted opines as nutrients in their plant tumor niche. These opines are produced by the host plant cells genetically modified by agrobacteria. They are imported into bacteria via solute-binding proteins (SBPs) in association with ATP-binding cassette transporters. The mannityl-opine family encompasses mannopine, mannopinic acid, agropine and agropinic acid. Structural and affinity data on mannopinic acid bound to SBPs are currently lacking while those of the three others mannityl opines are available. We investigated the molecular basis of two pathways for mannopinic acid uptake. MoaA was proposed as the specific SBP for mannopinic acid import in mannityl opines-assimilating agrobacteria, which was validated here using genetic studies and affinity measurements. We structurally characterized the mannopinic acid-binding mode of MoaA in two crystal forms at 2.05 and 1.57 Å resolution. We demonstrated that the non-specific SBP MotA, so far characterized as mannopine and Amadori compound importer, was also able to transport mannopinic acid. The structure of MotA bound to mannopinic acid at 2.2 Å resolution defines a different mannopinic acid-binding signature, similar to that of mannopine. Combining in vitro and in vivo approaches, this work allowed us to complete the characterization of the mannityl-opines assimilation pathways, highlighting the important role of two dual imports of agropinic and mannopinic acids. Our data shed new light on how the mannityl-opines contribute to the establishment of the ecological niche of agrobacteria from the early to the late stages of tumor development.
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11
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Kuzmanović N, Puławska J. Evolutionary Relatedness and Classification of Tumor-Inducing and Opine-Catabolic Plasmids in Three Rhizobium rhizogenes Strains Isolated from the Same Crown Gall Tumor. Genome Biol Evol 2019; 11:1525-1540. [PMID: 31028704 PMCID: PMC6546132 DOI: 10.1093/gbe/evz091] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2019] [Indexed: 12/12/2022] Open
Abstract
Plasmids play a crucial role in the ecology of agrobacteria. In this study, we sequenced tumor-inducing (Ti) and opine-catabolic (OC) plasmids in three Rhizobium rhizogenes (Agrobacterium biovar 2) strains isolated from the same crown gall tumor on “Colt” cherry rootstock and conducted comparative genomic analyses. Tumorigenic strains C5.7 and C6.5 carry nopaline-type Ti plasmids pTiC5.7/pTiC6.5, whereas the nonpathogenic strain Colt5.8 carries the nopaline-type OC plasmid pOC-Colt5.8. Overall, comparative genomic analysis indicated that pTiC5.7/pTiC6.5 and related Ti plasmids described before (pTiC58 and pTi-SAKURA) originate from a common ancestor, although they have diverged during evolution. On the other hand, plasmid pOC-Colt5.8 was most closely related to the well-known OC plasmid pAtK84b; however, analysis suggested that they had different evolutionary histories and seem to share a more distant common ancestor. Although the reconstruction of the evolutionary history of Ti and OC plasmids is still speculative, we hypothesized that nopaline-type Ti plasmid might originate from the nopaline-type OC plasmid. Our results suggested that OC plasmids are widespread and closely associated with crown gall tumors. Finally, we proposed a thorough scheme for classification of Ti and OC plasmids that is based on separate comparative analysis of each functional element of the plasmid studied.
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Affiliation(s)
- Nemanja Kuzmanović
- Julius Kühn-Institut, Federal Research Centre for Cultivated Plants (JKI), Institute for Epidemiology and Pathogen Diagnostics, Braunschweig, Germany
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12
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Gan HM, Szegedi E, Fersi R, Chebil S, Kovács L, Kawaguchi A, Hudson AO, Burr TJ, Savka MA. Insight Into the Microbial Co-occurrence and Diversity of 73 Grapevine ( Vitis vinifera) Crown Galls Collected Across the Northern Hemisphere. Front Microbiol 2019; 10:1896. [PMID: 31456792 PMCID: PMC6700373 DOI: 10.3389/fmicb.2019.01896] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 07/31/2019] [Indexed: 12/15/2022] Open
Abstract
Crown gall (CG) is a globally distributed and economically important disease of grapevine and other important crop plants. The causal agent of CG is Agrobacterium or Allorhizobium strains that harbor a tumor-inducing plasmid (pTi). The microbial community within the CG tumor has not been widely elucidated and it is not known if certain members of this microbial community promote or inhibit CG. This study investigated the microbiotas of grapevine CG tumor tissues from seven infected vineyards located in Hungary, Japan, Tunisia, and the United States. Heavy co-amplification of grapevine chloroplast and mitochondrial ribosomal RNA genes was observed with the widely used Illumina V3-V4 16S rRNA gene primers, requiring the design of a new reverse primer to enrich for bacterial 16S rRNA from CG tumors. The operational taxonomic unit (OTU) clustering approach is not suitable for CG microbiota analysis as it collapsed several ecologically distinct Agrobacterium species into a single OTU due to low interspecies genetic divergence. The CG microbial community assemblages were significantly different across sampling sites (ANOSIM global R = 0.63, p-value = 0.001) with evidence of site-specific differentially abundant ASVs. The presence of Allorhizobium vitis in the CG microbiota is almost always accompanied by Xanthomonas and Novosphingobium, the latter may promote the spread of pTi plasmid by way of acyl-homoserine lactone signal production, whereas the former may take advantage of the presence of substrates associated with plant cell wall growth and repair. The technical and biological insights gained from this study will contribute to the understanding of complex interaction between the grapevine and its microbial community and may facilitate better management of CG disease in the future.
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Affiliation(s)
- Han Ming Gan
- Deakin Genomics Centre, School of Life and Environmental Sciences, Deakin University, Geelong, VIC, Australia
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, VIC, Australia
- School of Science, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Ernõ Szegedi
- National Agricultural Research and Innovation Centre, Research Institute for Viticulture and Enology, Kecskemét, Hungary
| | - Rabeb Fersi
- Laboratory of Plant Molecular Physiology, Center of Biotechnology of Borj Cédria, Hammam-Lif, Tunisia
| | - Samir Chebil
- Laboratory of Plant Molecular Physiology, Center of Biotechnology of Borj Cédria, Hammam-Lif, Tunisia
| | - László Kovács
- Department of Biology, Missouri State University, Springfield, MO, United States
| | - Akira Kawaguchi
- Western Region Agricultural Research Center, National Agricultural and Food Research Organization, Fukuyama, Japan
| | - André O. Hudson
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY, United States
| | - Thomas J. Burr
- Section of Plant Pathology, School of Integrative Plant Sciences, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, United States
| | - Michael A. Savka
- Thomas H. Gosnell School of Life Sciences, Rochester Institute of Technology, Rochester, NY, United States
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Meyer T, Thiour-Mauprivez C, Wisniewski-Dyé F, Kerzaon I, Comte G, Vial L, Lavire C. Ecological Conditions and Molecular Determinants Involved in Agrobacterium Lifestyle in Tumors. FRONTIERS IN PLANT SCIENCE 2019; 10:978. [PMID: 31417593 PMCID: PMC6683767 DOI: 10.3389/fpls.2019.00978] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 07/11/2019] [Indexed: 05/07/2023]
Abstract
The study of pathogenic agents in their natural niches allows for a better understanding of disease persistence and dissemination. Bacteria belonging to the Agrobacterium genus are soil-borne and can colonize the rhizosphere. These bacteria are also well known as phytopathogens as they can cause tumors (crown gall disease) by transferring a DNA region (T-DNA) into a wide range of plants. Most reviews on Agrobacterium are focused on virulence determinants, T-DNA integration, bacterial and plant factors influencing the efficiency of genetic transformation. Recent research papers have focused on the plant tumor environment on the one hand, and genetic traits potentially involved in bacterium-plant interactions on the other hand. The present review gathers current knowledge about the special conditions encountered in the tumor environment along with the Agrobacterium genetic determinants putatively involved in bacterial persistence inside a tumor. By integrating recent metabolomic and transcriptomic studies, we describe how tumors develop and how Agrobacterium can maintain itself in this nutrient-rich but stressful and competitive environment.
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Affiliation(s)
- Thibault Meyer
- UMR Ecologie Microbienne, CNRS, INRA, VetAgro Sup, UCBL, Université de Lyon, Lyon, France
| | - Clémence Thiour-Mauprivez
- UMR Ecologie Microbienne, CNRS, INRA, VetAgro Sup, UCBL, Université de Lyon, Lyon, France
- Biocapteurs-Analyses-Environment, Universite de Perpignan Via Domitia, Perpignan, France
- Laboratoire de Biodiversite et Biotechnologies Microbiennes, USR 3579 Sorbonne Universites (UPMC) Paris 6 et CNRS Observatoire Oceanologique, Paris, France
| | | | - Isabelle Kerzaon
- UMR Ecologie Microbienne, CNRS, INRA, VetAgro Sup, UCBL, Université de Lyon, Lyon, France
| | - Gilles Comte
- UMR Ecologie Microbienne, CNRS, INRA, VetAgro Sup, UCBL, Université de Lyon, Lyon, France
| | - Ludovic Vial
- UMR Ecologie Microbienne, CNRS, INRA, VetAgro Sup, UCBL, Université de Lyon, Lyon, France
| | - Céline Lavire
- UMR Ecologie Microbienne, CNRS, INRA, VetAgro Sup, UCBL, Université de Lyon, Lyon, France
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Structural basis for two efficient modes of agropinic acid opine import into the bacterial pathogen Agrobacterium tumefaciens. Biochem J 2019; 476:165-178. [PMID: 30552142 DOI: 10.1042/bcj20180861] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 12/07/2018] [Accepted: 12/14/2018] [Indexed: 12/19/2022]
Abstract
Agrobacterium tumefaciens pathogens genetically modify their host plants to drive the synthesis of opines in plant tumors. The mannityl-opine family encompasses mannopine, mannopinic acid, agropine and agropinic acid. These opines serve as nutrients and are imported into bacteria via periplasmic-binding proteins (PBPs) in association with ABC transporters. Structural and affinity data on agropine and agropinic acid opines bound to PBPs are currently lacking. Here, we investigated the molecular basis of AgtB and AgaA, proposed as the specific PBP for agropine and agropinic acid import, respectively. Using genetic approaches and affinity measurements, we identified AgtB and its transporter as responsible for agropine uptake in agropine-assimilating agrobacteria. Nonetheless, we showed that AgtB binds agropinic acid with a higher affinity than agropine, and we structurally characterized the agropinic acid-binding mode through three crystal structures at 1.4, 1.74 and 1.9 Å resolution. In the crystallization time course, obtaining a crystal structure of AgtB with agropine was unsuccessful due to the spontaneous lactamization of agropine into agropinic acid. AgaA binds agropinic acid only with a similar affinity in nanomolar range as AgtB. The structure of AgaA bound to agropinic acid at 1.65 Å resolution defines a different agropinic acid-binding signature. Our work highlights the structural and functional characteristics of two efficient agropinic acid assimilation pathways, of which one is also involved in agropine assimilation.
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Gonzalez-Mula A, Torres M, Faure D. Integrative and deconvolution omics approaches to uncover the Agrobacterium tumefaciens lifestyle in plant tumors. PLANT SIGNALING & BEHAVIOR 2019; 14:e1581562. [PMID: 30774017 PMCID: PMC6422367 DOI: 10.1080/15592324.2019.1581562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Agrobacterium tumefaciens is a plant pathogen which provokes galls on roots and stems (crown-gall disease) and colonizes them. Two approaches combining omics were used to decipher the lifestyle of A. tumefaciens in plant tumors: an integrative approach when omics were used on A. tumefaciens cells collected from plant tumors, a deconvolution approach when omics were used on A. tumefaciens cells exploiting a single tumor metabolite in pure culture assay. This addendum highlights some recent results on the biotroph lifestyle of A. tumefaciens in plant tumors.
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Affiliation(s)
- Almudena Gonzalez-Mula
- Institute for integrative biology of the cell (I2BC), CNRS CEA Univ. Paris-Sud, University Paris-Saclay, Gif-sur-Yvette, France
| | - Marta Torres
- Institute for integrative biology of the cell (I2BC), CNRS CEA Univ. Paris-Sud, University Paris-Saclay, Gif-sur-Yvette, France
| | - Denis Faure
- Institute for integrative biology of the cell (I2BC), CNRS CEA Univ. Paris-Sud, University Paris-Saclay, Gif-sur-Yvette, France
- CONTACT Denis Faure Institute for integrative biology of the cell (I2BC), CNRS CEA Univ. Paris-Sud, University Paris-Saclay, Gif-sur-Yvette F-91190, France
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