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Weisberg AJ, Wu Y, Chang JH, Lai EM, Kuo CH. Virulence and Ecology of Agrobacteria in the Context of Evolutionary Genomics. ANNUAL REVIEW OF PHYTOPATHOLOGY 2023; 61:1-23. [PMID: 37164023 DOI: 10.1146/annurev-phyto-021622-125009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Among plant-associated bacteria, agrobacteria occupy a special place. These bacteria are feared in the field as agricultural pathogens. They cause abnormal growth deformations and significant economic damage to a broad range of plant species. However, these bacteria are revered in the laboratory as models and tools. They are studied to discover and understand basic biological phenomena and used in fundamental plant research and biotechnology. Agrobacterial pathogenicity and capability for transformation are one and the same and rely on functions encoded largely on their oncogenic plasmids. Here, we synthesize a substantial body of elegant work that elucidated agrobacterial virulence mechanisms and described their ecology. We review findings in the context of the natural diversity that has been recently unveiled for agrobacteria and emphasize their genomics and plasmids. We also identify areas of research that can capitalize on recent findings to further transform our understanding of agrobacterial virulence and ecology.
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Affiliation(s)
- Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA;
| | - Yu Wu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan;
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA;
| | - Erh-Min Lai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan;
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan
- Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
| | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan;
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan
- Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
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Hooykaas PJJ. The Ti Plasmid, Driver of Agrobacterium Pathogenesis. PHYTOPATHOLOGY 2023; 113:594-604. [PMID: 37098885 DOI: 10.1094/phyto-11-22-0432-ia] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The phytopathogenic bacterium Agrobacterium tumefaciens causes crown gall disease in plants, characterized by the formation of tumor-like galls where wounds were present. Nowadays, however, the bacterium and its Ti (tumor-inducing) plasmid is better known as an effective vector for the genetic manipulation of plants and fungi. In this review, I will briefly summarize some of the major discoveries that have led to this bacterium now playing such a prominent role worldwide in plant and fungal research at universities and research institutes and in agricultural biotechnology for the production of genetically modified crops. I will then delve a little deeper into some aspects of Agrobacterium biology and discuss the diversity among agrobacteria and the taxonomic position of these bacteria, the diversity in Ti plasmids, the molecular mechanism used by the bacteria to transform plants, and the discovery of protein translocation from the bacteria to host cells as an essential feature of Agrobacterium-mediated transformation.
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Kuzmanović N, diCenzo GC, Bunk B, Spröer C, Frühling A, Neumann‐Schaal M, Overmann J, Smalla K. Genomics of the “tumorigenes” clade of the family Rhizobiaceae and description of Rhizobium rhododendri sp. nov. Microbiologyopen 2023; 12:e1352. [PMID: 37186225 PMCID: PMC10064268 DOI: 10.1002/mbo3.1352] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 03/08/2023] [Accepted: 03/08/2023] [Indexed: 04/03/2023] Open
Abstract
Tumorigenic members of the family Rhizobiaceae, known as agrobacteria, are responsible for crown and cane gall diseases of various crops worldwide. Tumorigenic agrobacteria are commonly found in the genera Agrobacterium, Allorhizobium, and Rhizobium. In this study, we analyzed a distinct “tumorigenes” clade of the genus Rhizobium, which includes the tumorigenic species Rhizobium tumorigenes, as well as strains causing crown gall disease on rhododendron. Here, high‐quality, closed genomes of representatives of the “tumorigenes” clade were generated, followed by comparative genomic and phylogenomic analyses. Additionally, the phenotypic characteristics of representatives of the “tumorigenes” clade were analyzed. Our results showed that the tumorigenic strains isolated from rhododendron represent a novel species of the genus Rhizobium for which the name Rhizobium rhododendri sp. nov. is proposed. This species also includes additional strains originating from blueberry and Himalayan blackberry in the United States, whose genome sequences were retrieved from GenBank. Both R. tumorigenes and R. rhododendri contain multipartite genomes, including a chromosome, putative chromids, and megaplasmids. Synteny and phylogenetic analyses indicated that a large putative chromid of R. rhododendri resulted from the cointegration of an ancestral megaplasmid and two putative chromids, following its divergence from R. tumorigenes. Moreover, gene clusters specific for both species of the “tumorigenes” clade were identified, and their biological functions and roles in the ecological diversification of R. rhododendri and R. tumorigenes were predicted and discussed.
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Affiliation(s)
- Nemanja Kuzmanović
- Julius Kühn Institute (JKI), Federal Research Centre for Cultivated PlantsInstitute for Plant Protection in Horticulture and Urban GreenBraunschweigGermany
| | | | - Boyke Bunk
- Leibniz Institute DSMZ‐German Collection of Microorganisms and Cell CulturesBraunschweigGermany
| | - Cathrin Spröer
- Leibniz Institute DSMZ‐German Collection of Microorganisms and Cell CulturesBraunschweigGermany
| | - Anja Frühling
- Leibniz Institute DSMZ‐German Collection of Microorganisms and Cell CulturesBraunschweigGermany
| | - Meina Neumann‐Schaal
- Leibniz Institute DSMZ‐German Collection of Microorganisms and Cell CulturesBraunschweigGermany
| | - Jörg Overmann
- Leibniz Institute DSMZ‐German Collection of Microorganisms and Cell CulturesBraunschweigGermany
- MicrobiologyTechnical University of BraunschweigBraunschweigGermany
| | - Kornelia Smalla
- Julius Kühn Institute (JKI), Federal Research Centre for Cultivated PlantsInstitute for Epidemiology and Pathogen DiagnosticsBraunschweigGermany
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Weisberg AJ, Miller M, Ream W, Grünwald NJ, Chang JH. Diversification of plasmids in a genus of pathogenic and nitrogen-fixing bacteria. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200466. [PMID: 34839700 PMCID: PMC8628075 DOI: 10.1098/rstb.2020.0466] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Members of the agrobacteria-rhizobia complex (ARC) have multiple and diverse plasmids. The extent to which these plasmids are shared and the consequences of their interactions are not well understood. We extracted over 4000 plasmid sequences from 1251 genome sequences and constructed a network to reveal interactions that have shaped the evolutionary histories of oncogenic virulence plasmids. One newly discovered type of oncogenic plasmid is a mosaic with three incomplete, but complementary and partially redundant virulence loci. Some types of oncogenic plasmids recombined with accessory plasmids or acquired large regions not known to be associated with pathogenicity. We also identified two classes of partial virulence plasmids. One class is potentially capable of transforming plants, but not inciting disease symptoms. Another class is inferred to be incomplete and non-functional but can be found as coresidents of the same strain and together are predicted to confer pathogenicity. The modularity and capacity for some plasmids to be transmitted broadly allow them to diversify, convergently evolve adaptive plasmids and shape the evolution of genomes across much of the ARC. This article is part of the theme issue 'The secret lives of microbial mobile genetic elements'.
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Affiliation(s)
- Alexandra J. Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
| | - Marilyn Miller
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
| | - Walt Ream
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA
| | - Niklaus J. Grünwald
- Horticultural Crops Research Laboratory, United States Department of Agriculture and Agricultural Research Service, Corvallis, OR 97330, USA
| | - Jeff H. Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
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Chou L, Lin YC, Haryono M, Santos MNM, Cho ST, Weisberg AJ, Wu CF, Chang JH, Lai EM, Kuo CH. Modular evolution of secretion systems and virulence plasmids in a bacterial species complex. BMC Biol 2022; 20:16. [PMID: 35022048 PMCID: PMC8756689 DOI: 10.1186/s12915-021-01221-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/23/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Many named species as defined in current bacterial taxonomy correspond to species complexes. Uncertainties regarding the organization of their genetic diversity challenge research efforts. We utilized the Agrobacterium tumefaciens species complex (a.k.a. Agrobacterium biovar 1), a taxon known for its phytopathogenicity and applications in transformation, as a study system and devised strategies for investigating genome diversity and evolution of species complexes. RESULTS We utilized 35 genome assemblies, including 14 newly generated ones, to achieve a phylogenetically balanced sampling of A. tumefaciens. Our genomic analysis suggested that the 10 genomospecies described previously are distinct biological species and supported a quantitative guideline for species delineation. Furthermore, our inference of gene content and core-genome phylogeny allowed for investigations of genes critical in fitness and ecology. For the type VI secretion system (T6SS) involved in interbacterial competition and thought to be conserved, we detected multiple losses and one horizontal gene transfer. For the tumor-inducing plasmids (pTi) and pTi-encoded type IV secretion system (T4SS) that are essential for agrobacterial phytopathogenicity, we uncovered novel diversity and hypothesized their involvement in shaping this species complex. Intriguingly, for both T6SS and T4SS, genes encoding structural components are highly conserved, whereas extensive diversity exists for genes encoding effectors and other proteins. CONCLUSIONS We demonstrate that the combination of a phylogeny-guided sampling scheme and an emphasis on high-quality assemblies provides a cost-effective approach for robust analysis in evolutionary genomics. We show that the T6SS VgrG proteins involved in specific effector binding and delivery can be classified into distinct types based on domain organization. The co-occurrence patterns of VgrG-associated domains and the neighboring genes that encode different chaperones/effectors can be used to infer possible interacting partners. Similarly, the associations between plant host preference and the pTi type among these strains can be used to infer phenotype-genotype correspondence. Our strategies for multi-level investigations at scales that range from whole genomes to intragenic domains and phylogenetic depths from between- to within-species are applicable to other bacteria. Furthermore, modularity observed in the molecular evolution of genes and domains is useful for inferring functional constraints and informing experimental works.
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Affiliation(s)
- Lin Chou
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yu-Chen Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Mindia Haryono
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Mary Nia M Santos
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.,Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan.,Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Shu-Ting Cho
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
| | - Chih-Feng Wu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.,Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
| | - Erh-Min Lai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.,Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan.,Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
| | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan. .,Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan. .,Biotechnology Center, National Chung Hsing University, Taichung, Taiwan.
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Hooykaas MJG, Hooykaas PJJ. Complete genomic sequence and phylogenomics analysis of Agrobacterium strain AB2/73: a new Rhizobium species with a unique mega-Ti plasmid. BMC Microbiol 2021; 21:295. [PMID: 34711172 PMCID: PMC8554961 DOI: 10.1186/s12866-021-02358-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 10/06/2021] [Indexed: 01/18/2023] Open
Abstract
Background The Agrobacterium strain AB2/73 has a unique host range for the induction of crown gall tumors, and contains an exceptionally large, over 500 kbp mega Ti plasmid. We used whole genome sequencing to fully characterize and comparatively analyze the complex genome of strain AB2/73, including its Ti plasmid and virulence factors. Results We obtained a high-quality, full genomic sequence of AB2/73 by a combination of short-read Illumina sequencing and long-read Nanopore sequencing. The AB2/73 genome has a total size of 7,266,754 bp with 59.5% GC for which 7012 genes (6948 protein coding sequences) are predicted. Phylogenetic and comparative genomics analysis revealed that strain AB2/73 does not belong to the genus Agrobacterium, but to a new species in the genus Rhizobium, which is most related to Rhizobium tropici. In addition to the chromosome, the genome consists of 6 plasmids of which the largest two, of more than 1 Mbp, have chromid-like properties. The mega Ti plasmid is 605 kbp in size and contains two, one of which is incomplete, repABC replication units and thus appears to be a cointegrate consisting of about 175 kbp derived from an unknown Ti plasmid linked to 430 kbp from another large plasmid. In pTiAB2/73 we identified a complete set of virulence genes and two T-DNAs. Besides the previously described T-DNA we found a larger, second T-DNA containing a 6b-like onc gene and the acs gene for agrocinopine synthase. Also we identified two clusters of genes responsible for opine catabolism, including an acc-operon for agrocinopine degradation, and genes putatively involved in ridéopine catabolism. The plasmid also harbours tzs, iaaM and iaaH genes for the biosynthesis of the plant growth regulators cytokinin and auxin. Conclusions The comparative genomics analysis of the high quality genome of strain AB2/73 provided insight into the unusual phylogeny and genetic composition of the limited host range Agrobacterium strain AB2/73. The description of its unique genomic composition and of all the virulence determinants in pTiAB2/73 will be an invaluable tool for further studies into the special host range properties of this bacterium. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02358-0.
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de Lajudie P, Mousavi SA, Young JPW. International Committee on Systematics of Prokaryotes Subcommittee on the Taxonomy of Rhizobia and Agrobacteria Minutes of the closed meeting by videoconference, 6 July 2020. Int J Syst Evol Microbiol 2021; 71. [PMID: 33956594 PMCID: PMC8289204 DOI: 10.1099/ijsem.0.004784] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- Philippe de Lajudie
- IRD, University of Montpellier, CIRAD, INRAE, SupAgro, LSTM, Montpellier, France
| | - Seyed Abdollah Mousavi
- Ecosystems and Environment Research Programme, University of Helsinki, Finland.,Department of Biology, University of Turku, Finland
| | - J Peter W Young
- Department of Biology, University of York, York YO10 5DD, UK
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Phylogenomics reveals the basis of adaptation of Pseudorhizobium species to extreme environments and supports a taxonomic revision of the genus. Syst Appl Microbiol 2020; 44:126165. [PMID: 33360413 DOI: 10.1016/j.syapm.2020.126165] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 11/10/2020] [Accepted: 11/11/2020] [Indexed: 11/21/2022]
Abstract
The family Rhizobiaceae includes many genera of soil bacteria, often isolated for their association with plants. Herein, we investigate the genomic diversity of a group of Rhizobium species and unclassified strains isolated from atypical environments, including seawater, rock matrix or polluted soil. Based on whole-genome similarity and core genome phylogeny, we show that this group corresponds to the genus Pseudorhizobium. We thus reclassify Rhizobium halotolerans, R. marinum, R. flavum and R. endolithicum as P. halotolerans sp. nov., P. marinum comb. nov., P. flavum comb. nov. and P. endolithicum comb. nov., respectively, and show that P. pelagicum is a synonym of P. marinum. We also delineate a new chemolithoautotroph species, P. banfieldiae sp. nov., whose type strain is NT-26T (=DSM 106348T=CFBP 8663T). This genome-based classification was supported by a chemotaxonomic comparison, with increasing taxonomic resolution provided by fatty acid, protein and metabolic profiles. In addition, we used a phylogenetic approach to infer scenarios of duplication, horizontal transfer and loss for all genes in the Pseudorhizobium pangenome. We thus identify the key functions associated with the diversification of each species and higher clades, shedding light on the mechanisms of adaptation to their respective ecological niches. Respiratory proteins acquired at the origin of Pseudorhizobium were combined with clade-specific genes to enable different strategies for detoxification and nutrition in harsh, nutrient-poor environments.
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Kuzmanović N, Behrens P, Idczak E, Wagner S, Götz M, Spröer C, Bunk B, Overmann J, Smalla K. A Novel Group of Rhizobium tumorigenes-Like Agrobacteria Associated with Crown Gall Disease of Rhododendron and Blueberry. PHYTOPATHOLOGY 2019; 109:1840-1848. [PMID: 31294681 DOI: 10.1094/phyto-05-19-0167-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Crown gall is an economically important and widespread plant disease caused by tumorigenic bacteria that are commonly affiliated within the genera Agrobacterium, Allorhizobium, and Rhizobium. Although crown gall disease was reported to occur on rhododendron, literature data regarding this disease are limited. In this study, an atypical group of tumorigenic agrobacteria belonging to the genus Rhizobium was identified as a causative agent of crown gall on rhododendron. Genome analysis suggested that tumorigenic bacteria isolated from rhododendron tumors are most closely related to Rhizobium tumorigenes, a new tumorigenic bacterium discovered recently on blackberry in Serbia. However, R. tumorigenes and novel rhododendron strains belong to separate species and form a homogenous clade within the genus Rhizobium, which we named the "tumorigenes" clade. Moreover, tumorigenic bacteria isolated from rhododendron seem to carry a distinct tumor-inducing (Ti) plasmid, compared with those carried by R. tumorigenes strains and Ti plasmids described thus far. To facilitate rapid identification of bacteria belonging to the "tumorigenes" clade, regardless of whether they are pathogenic or not, a conventional PCR method targeting putative chromosomal gene-encoding flagellin protein FlaA was developed in this study. Finally, our results suggested that this novel group of tumorigenic agrobacteria occurs on blueberry but it cannot be excluded that it is distributed more widely.
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Affiliation(s)
- Nemanja Kuzmanović
- Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, 38104 Braunschweig, Germany
| | - Patric Behrens
- Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, 38104 Braunschweig, Germany
| | - Elke Idczak
- Institute for Plant Protection in Horticulture and Forests, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, 38104 Braunschweig, Germany
| | - Stefan Wagner
- Institute for Plant Protection in Horticulture and Forests, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, 38104 Braunschweig, Germany
| | - Monika Götz
- Institute for Plant Protection in Horticulture and Forests, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, 38104 Braunschweig, Germany
| | - Cathrin Spröer
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, 38124 Braunschweig, Germany
| | - Boyke Bunk
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, 38124 Braunschweig, Germany
| | - Jörg Overmann
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, 38124 Braunschweig, Germany
- Microbiology, Braunschweig University of Technology, 38106 Braunschweig, Germany
| | - Kornelia Smalla
- Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, 38104 Braunschweig, Germany
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