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Kuzmanović N, Wolf J, Will SE, Smalla K, diCenzo GC, Neumann-Schaal M. Diversity and Evolutionary History of Ti Plasmids of "tumorigenes" Clade of Rhizobium spp. and Their Differentiation from Other Ti and Ri Plasmids. Genome Biol Evol 2023; 15:evad133. [PMID: 37463407 PMCID: PMC10410297 DOI: 10.1093/gbe/evad133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/05/2023] [Accepted: 07/13/2023] [Indexed: 07/20/2023] Open
Abstract
Agrobacteria are important plant pathogens responsible for crown/cane gall and hairy root diseases. Crown/cane gall disease is associated with strains carrying tumor-inducing (Ti) plasmids, while hairy root disease is caused by strains harboring root-inducing (Ri) plasmids. In this study, we analyzed the sequences of Ti plasmids of the novel "tumorigenes" clade of the family Rhizobiaceae ("tumorigenes" Ti plasmids), which includes two species, Rhizobium tumorigenes and Rhizobium rhododendri. The sequences of reference Ti/Ri plasmids were also included, which was followed by a comparative analysis of their backbone and accessory regions. The "tumorigenes" Ti plasmids have novel opine signatures compared with other Ti/Ri plasmids characterized so far. The first group exemplified by pTi1078 is associated with production of agrocinopine, nopaline, and ridéopine in plant tumors, while the second group comprising pTi6.2 is responsible for synthesis of leucinopine. Bioinformatic and chemical analyses, including opine utilization assays, indicated that leucinopine associated with pTi6.2 most likely has D,L stereochemistry, unlike the L,L-leucinopine produced in tumors induced by reference strains Chry5 and Bo542. Most of the "tumorigenes" Ti plasmids have conjugative transfer system genes that are unusual for Ti plasmids, composed of avhD4/avhB and traA/mobC/parA regions. Next, our results suggested that "tumorigenes" Ti plasmids have a common origin, but they diverged through large-scale recombination events, through recombination with single or multiple distinct Ti/Ri plasmids. Lastly, we showed that Ti/Ri plasmids could be differentiated based on pairwise Mash or average amino-acid identity distance clustering, and we supply a script to facilitate application of the former approach by other researchers.
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Affiliation(s)
- Nemanja Kuzmanović
- Julius Kühn Institute (JKI), Federal Research Centre for Cultivated Plants, Institute for Plant Protection in Horticulture and Urban Green, Braunschweig, Germany
| | - Jacqueline Wolf
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Sabine Eva Will
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Kornelia Smalla
- Julius Kühn Institute (JKI), Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Braunschweig, Germany
| | - George C diCenzo
- Department of Biology, Queen's University, Kingston, Ontario, Canada
| | - Meina Neumann-Schaal
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
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Characterization of the Agrobacterium octopine-cucumopine catabolic plasmid pAtAg67. Plasmid 2022; 121:102629. [DOI: 10.1016/j.plasmid.2022.102629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/06/2022] [Accepted: 03/29/2022] [Indexed: 11/21/2022]
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Nabi N, Ben Hafsa A, Gaillard V, Nesme X, Chaouachi M, Vial L. Evolutionary classification of tumor- and root-inducing plasmids based on T-DNAs and virulence regions. Mol Phylogenet Evol 2022; 169:107388. [PMID: 35017066 DOI: 10.1016/j.ympev.2022.107388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 11/15/2020] [Accepted: 12/08/2021] [Indexed: 11/19/2022]
Abstract
Tumor-inducing (Ti) and root-inducing (Ri) plasmids of Agrobacterium that display a large diversity are involved in crown gall and hairy root plant diseases. Their phylogenetic relationships were inferred from an exhaustive set of Ti and Ri plasmids (including 36 new complete Ti plasmids) by focusing on T-DNA and virulence regions. The opine synthase gene content of T-DNAs revealed 13 opine types corresponding to former classifications based on opines detected in diseased plants, while the T-DNA gene content more finely separate opine types in 18 T-DNA organizations. This classification was supported by the phylogeny of T-DNA oncogenes of Ti plasmids. The five gene organizations found in Ti/Ri vir regions was supported by the phylogeny of common vir genes. The vir organization was found to be likely an ancestral plasmid trait separating "classic" Ti plasmids (with one or two T-DNAs) and "Ri and vine-Ti" plasmids. A scenario generally supported by the repABC phylogeny. T-DNAs likely evolved later with the acquisition of opine characteristics as last steps in the Ti/Ri plasmid evolution. This novel evolutionary classification of Ti/Ri plasmids was found to be relevant for accurate crown gall and hairy root epidemiology.
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Affiliation(s)
- Nesrine Nabi
- Unité de Recherche UR17ES30 Génomique, Biotechnologie et Stratégies Antivirales, Institut Supérieur de Biotechnologie, Université de Monastir, Monastir, Tunisie.
| | - Ahmed Ben Hafsa
- Unité de Recherche UR17ES30 Génomique, Biotechnologie et Stratégies Antivirales, Institut Supérieur de Biotechnologie, Université de Monastir, Monastir, Tunisie
| | - Vincent Gaillard
- Laboratoire d'Ecologie Microbienne (LEM), UCBL, CNRS, INRAE, VetAgro Sup, Univ Lyon, F-69622 Villeurbanne Cedex, France
| | - Xavier Nesme
- Laboratoire d'Ecologie Microbienne (LEM), UCBL, CNRS, INRAE, VetAgro Sup, Univ Lyon, F-69622 Villeurbanne Cedex, France
| | - Maher Chaouachi
- Unité de Recherche UR17ES30 Génomique, Biotechnologie et Stratégies Antivirales, Institut Supérieur de Biotechnologie, Université de Monastir, Monastir, Tunisie
| | - Ludovic Vial
- Laboratoire d'Ecologie Microbienne (LEM), UCBL, CNRS, INRAE, VetAgro Sup, Univ Lyon, F-69622 Villeurbanne Cedex, France.
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Shao S, van Heusden GPH, Hooykaas PJJ. Complete Sequence of Succinamopine Ti-Plasmid pTiEU6 Reveals Its Evolutionary Relatedness with Nopaline-Type Ti-Plasmids. Genome Biol Evol 2020; 11:2480-2491. [PMID: 31386108 PMCID: PMC6733357 DOI: 10.1093/gbe/evz173] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2019] [Indexed: 01/14/2023] Open
Abstract
Agrobacterium tumefaciens is the etiological agent of plant crown gall disease, which is induced by the delivery of a set of oncogenic genes into plant cells from its tumor-inducing (Ti) plasmid. Here we present the first complete sequence of a succinamopine-type Ti-plasmid. Plasmid pTiEU6 is comprised of 176,375 bp with an overall GC content of 56.1% and 195 putative protein-coding sequences could be identified. This Ti-plasmid is most closely related to nopaline-type Ti-plasmids. It contains a single T-region which is somewhat smaller than that of the nopaline-type Ti-plasmids and in which the gene for nopaline synthesis is replaced by a gene (sus) for succinamopine synthesis. Also in pTiEU6 the nopaline catabolic genes are replaced by genes for succinamopine catabolism. In order to trace the evolutionary origin of pTiEU6, we sequenced six nopaline Ti-plasmids to enlarge the scope for comparison to this class of plasmids. Average nucleotide identity analysis revealed that pTiEU6 was most closely related to nopaline Ti-plasmids pTiT37 and pTiSAKURA. In line with this traces of several transposable elements were present in all the nopaline Ti plasmids and in pTiEU6, but one specific transposable element insertion, that of a copy of IS1182, was present at the same site only in pTiEU6, pTiT37, and pTiSAKURA, but not in the other Ti plasmids. This suggests that pTiEU6 evolved after diversification of nopaline Ti-plasmids by DNA recombination between a pTiT37-like nopaline Ti-plasmid and another plasmid, thus introducing amongst others new catabolic genes matching a new opine synthase gene for succinamopine synthesis.
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Affiliation(s)
- Shuai Shao
- Molecular and Developmental Genetics, Institute of Biology, Leiden University, The Netherlands
| | - G Paul H van Heusden
- Molecular and Developmental Genetics, Institute of Biology, Leiden University, The Netherlands
| | - Paul J J Hooykaas
- Molecular and Developmental Genetics, Institute of Biology, Leiden University, The Netherlands
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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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Lacroix B, Citovsky V. Pathways of DNA Transfer to Plants from Agrobacterium tumefaciens and Related Bacterial Species. ANNUAL REVIEW OF PHYTOPATHOLOGY 2019; 57:231-251. [PMID: 31226020 PMCID: PMC6717549 DOI: 10.1146/annurev-phyto-082718-100101] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Genetic transformation of host plants by Agrobacterium tumefaciens and related species represents a unique model for natural horizontal gene transfer. Almost five decades of studying the molecular interactions between Agrobacterium and its host cells have yielded countless fundamental insights into bacterial and plant biology, even though several steps of the DNA transfer process remain poorly understood. Agrobacterium spp. may utilize different pathways for transferring DNA, which likely reflects the very wide host range of Agrobacterium. Furthermore, closely related bacterial species, such as rhizobia, are able to transfer DNA to host plant cells when they are provided with Agrobacterium DNA transfer machinery and T-DNA. Homologs of Agrobacterium virulence genes are found in many bacterial genomes, but only one non-Agrobacterium bacterial strain, Rhizobium etli CFN42, harbors a complete set of virulence genes and can mediate plant genetic transformation when carrying a T-DNA-containing plasmid.
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Affiliation(s)
- Benoît Lacroix
- Department of Biochemistry and Cell Biology, State University of New York, Stony Brook, New York 11794-5215, USA;
| | - Vitaly Citovsky
- Department of Biochemistry and Cell Biology, State University of New York, Stony Brook, New York 11794-5215, USA;
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The Ecology of Agrobacterium vitis and Management of Crown Gall Disease in Vineyards. Curr Top Microbiol Immunol 2019; 418:15-53. [PMID: 29556824 DOI: 10.1007/82_2018_85] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
Agrobacterium vitis is the primary causal agent of grapevine crown gall worldwide. Symptoms of grapevine crown gall disease include tumor formation on the aerial plant parts, whereas both tumorigenic and nontumorigenic strains of A. vitis cause root necrosis. Genetic and genomic analyses indicated that A. vitis is distinguishable from the members of the Agrobacterium genus and its transfer to the genus Allorhizobium was suggested. A. vitis is genetically diverse, with respect to both chromosomal and plasmid DNA. Its pathogenicity is mainly determined by a large conjugal tumor-inducing (Ti) plasmid characterized by a mosaic structure with conserved and variable regions. Traditionally, A. vitis Ti plasmids and host strains were differentiated into octopine/cucumopine, nopaline, and vitopine groups, based on opine markers. However, tumorigenic and nontumorigenic strains of A. vitis may carry other ecologically important plasmids, such as tartrate- and opine-catabolic plasmids. A. vitis colonizes vines endophytically. It is also able to survive epiphytically on grapevine plants and is detected in soil exclusively in association with grapevine plants. Because A. vitis persists systemically in symptomless grapevine plants, it can be efficiently disseminated to distant geographical areas via international trade of propagation material. The use of healthy planting material in areas with no history of the crown gall represents the crucial measure of disease management. Moreover, biological control and production of resistant grape varieties are encouraging as future control measures.
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Niche Construction and Exploitation by Agrobacterium: How to Survive and Face Competition in Soil and Plant Habitats. Curr Top Microbiol Immunol 2018; 418:55-86. [PMID: 29556826 DOI: 10.1007/82_2018_83] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Agrobacterium populations live in different habitats (bare soil, rhizosphere, host plants), and hence face different environmental constraints. They have evolved the capacity to exploit diverse resources and to escape plant defense and competition from other microbiota. By modifying the genome of their host, Agrobacterium populations exhibit the remarkable ability to construct and exploit the ecological niche of the plant tumors that they incite. This niche is characterized by the accumulation of specific, low molecular weight compounds termed opines that play a critical role in Agrobacterium 's lifestyle. We present and discuss the functions, advantages, and costs associated with this niche construction and exploitation.
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Abstract
The transfer of T-DNA sequences from Agrobacterium to plant cells is a well-understood process of natural genetic engineering. The expression of T-DNA genes in plants leads to tumors, hairy roots, or transgenic plants. The transformed cells multiply and synthesize small molecules, called opines, used by Agrobacteria for their growth. Several T-DNA genes stimulate or influence plant growth. Among these, iaaH and iaaM encode proteins involved in auxin synthesis, whereas ipt encodes a protein involved in cytokinin synthesis. Growth can also be induced or modified by other T-DNA genes, collectively called plast genes (for phenotypic plasticity). The plast genes are defined by their common ancestry and are mostly found on T-DNAs. They can influence plant growth in different ways, but the molecular basis of their morphogenetic activity remains largely unclear. Only some plast genes, such as 6b, rolB, rolC, and orf13, have been studied in detail. Plast genes have a significant potential for applied research and may be used to modify the growth of crop plants. In this review, I summarize the most important findings and models from 30 years of plast gene research and propose some outlooks for the future.
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Chen K, Otten L. Natural Agrobacterium Transformants: Recent Results and Some Theoretical Considerations. FRONTIERS IN PLANT SCIENCE 2017; 8:1600. [PMID: 28966626 PMCID: PMC5606197 DOI: 10.3389/fpls.2017.01600] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 08/31/2017] [Indexed: 05/19/2023]
Abstract
Agrobacterium rhizogenes causes hairy root growth on a large number of plant species. It does so by transferring specific DNA fragments (T-DNA) from its root-inducing plasmid (pRi) into plant cells. Expression of T-DNA genes leads to abnormal root growth and production of specific metabolites (opines) which are taken up by the bacterium and used for its growth. Recent work has shown that several Nicotiana, Linaria, and Ipomoea species contain T-DNA genes from A. rhizogenes in their genomes. Plants carrying such T-DNAs (called cellular T-DNA or cT-DNA) can be considered as natural transformants. In the Nicotiana genus, seven different T-DNAs are found originating from different Agrobacterium strains, and in the Tomentosae section no <4 successive insertion events took place. In several cases cT-DNA genes were found to be expressed. In some Nicotiana tabacum cultivars the opine synthesis gene TB-mas2' is expressed in the roots. These cultivars were found to produce opines. Here we review what is known about natural Agrobacterium transformants, develop a theoretical framework to analyze this unusual phenomenon, and provide some outlines for further research.
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Affiliation(s)
- Ke Chen
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong UniversityShanghai, China
| | - Léon Otten
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS)Strasbourg, France
- *Correspondence: Léon Otten
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Ito M, Machida Y. Reprogramming of plant cells induced by 6b oncoproteins from the plant pathogen Agrobacterium. JOURNAL OF PLANT RESEARCH 2015; 128:423-435. [PMID: 25694001 DOI: 10.1007/s10265-014-0694-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 11/25/2014] [Indexed: 06/04/2023]
Abstract
Reprogramming of plant cells is an event characterized by dedifferentiation, reacquisition of totipotency, and enhanced cell proliferation, and is typically observed during formation of the callus, which is dependent on plant hormones. The callus-like cell mass, called a crown gall tumor, is induced at the sites of infection by Agrobacterium species through the expression of hormone-synthesizing genes encoded in the T-DNA region, which probably involves a similar reprogramming process. One of the T-DNA genes, 6b, can also by itself induce reprogramming of differentiated cells to generate tumors and is therefore recognized as an oncogene acting in plant cells. The 6b genes belong to a group of Agrobacterium T-DNA genes, which include rolB, rolC, and orf13. These genes encode proteins with weakly conserved sequences and may be derived from a common evolutionary origin. Most of these members can modify plant growth and morphogenesis in various ways, in most cases without affecting the levels of plant hormones. Recent studies have suggested that the molecular function of 6b might be to modify the patterns of transcription in the host nuclei, particularly by directly targeting the host transcription factors or by changing the epigenetic status of the host chromatin through intrinsic histone chaperone activity. In light of the recent findings on zygotic resetting of nucleosomal histone variants in Arabidopsis thaliana, one attractive idea is that acquisition of totipotency might be facilitated by global changes of epigenetic status, which might be induced by replacement of histone variants in the zygote after fertilization and in differentiated cells upon stimulation by plant hormones as well as by expression of the 6b gene.
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Affiliation(s)
- Masaki Ito
- Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa-ku, Nagoya, 464-8601, Japan,
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Chen K, Dorlhac de Borne F, Szegedi E, Otten L. Deep sequencing of the ancestral tobacco species Nicotiana tomentosiformis reveals multiple T-DNA inserts and a complex evolutionary history of natural transformation in the genus Nicotiana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 80:669-82. [PMID: 25219519 DOI: 10.1111/tpj.12661] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 07/30/2014] [Accepted: 08/29/2014] [Indexed: 05/21/2023]
Abstract
Nicotiana species carry cellular T-DNA sequences (cT-DNAs), acquired by Agrobacterium-mediated transformation. We characterized the cT-DNA sequences of the ancestral Nicotiana tabacum species Nicotiana tomentosiformis by deep sequencing. N. tomentosiformis contains four cT-DNA inserts derived from different Agrobacterium strains. Each has an incomplete inverted-repeat structure. TA is similar to part of the Agrobacterium rhizogenes 1724 mikimopine-type T-DNA, but has unusual orf14 and mis genes. TB carries a 1724 mikimopine-type orf14-mis fragment and a mannopine-agropine synthesis region (mas2-mas1-ags). The mas2' gene codes for an active enzyme. TC is similar to the left part of the A. rhizogenes A4 T-DNA, but also carries octopine synthase-like (ocl) and c-like genes normally found in A. tumefaciens. TD shows a complex rearrangement of T-DNA fragments similar to the right end of the A4 TL-DNA, and including an orf14-like gene and a gene with unknown function, orf511. The TA, TB, TC and TD insertion sites were identified by alignment with N. tabacum and Nicotiana sylvestris sequences. The divergence values for the TA, TB, TC and TD repeats provide an estimate for their relative introduction times. A large deletion has occurred in the central part of the N. tabacum cv. Basma/Xanthi TA region, and another deletion removed the complete TC region in N. tabacum. Nicotiana otophora lacks TA, TB and TD, but contains TC and another cT-DNA, TE. This analysis, together with that of Nicotiana glauca and other Nicotiana species, indicates multiple sequential insertions of cT-DNAs during the evolution of the genus Nicotiana.
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Affiliation(s)
- Ke Chen
- Department of Molecular Mechanisms of Phenotypic Plasticity, Institut de Biologie Moléculaire des Plantes du C. N. R. S., Rue du Général Zimmer 12, 67084, Strasbourg, France
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Ishibashi N, Kitakura S, Terakura S, Machida C, Machida Y. Protein encoded by oncogene 6b from Agrobacterium tumefaciens has a reprogramming potential and histone chaperone-like activity. FRONTIERS IN PLANT SCIENCE 2014; 5:572. [PMID: 25389429 PMCID: PMC4211554 DOI: 10.3389/fpls.2014.00572] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 10/05/2014] [Indexed: 05/31/2023]
Abstract
Crown gall tumors are formed mainly by actions of a group of genes in the T-DNA that is transferred from Agrobacterium tumefaciens and integrated into the nuclear DNA of host plants. These genes encode enzymes for biosynthesis of auxin and cytokinin in plant cells. Gene 6b in the T-DNA affects tumor morphology and this gene alone is able to induce small tumors on certain plant species. In addition, unorganized calli are induced from leaf disks of tobacco that are incubated on phytohormone-free media; shooty teratomas, and morphologically abnormal plants, which might be due to enhanced competence of cell division and meristematic states, are regenerated from the calli. Thus, the 6b gene appears to stimulate a reprogramming process in plants. To uncover mechanisms behind this process, various approaches including the yeast-two-hybrid system have been exploited and histone H3 was identified as one of the proteins that interact with 6b. It has been also demonstrated that 6b acts as a histone H3 chaperon in vitro and affects the expression of various genes related to cell division competence and the maintenance of meristematic states. We discuss current views on a role of 6b protein in tumorigenesis and reprogramming in plants.
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Affiliation(s)
- Nanako Ishibashi
- Division of Biological Science, Graduate School of Science, Nagoya UniversityNagoya, Japan
| | - Saeko Kitakura
- Division of Biological Science, Graduate School of Science, Nagoya UniversityNagoya, Japan
- Graduate School of Bioscience and Biotechnology, Chubu UniversityKasugai, Japan
| | - Shinji Terakura
- Division of Biological Science, Graduate School of Science, Nagoya UniversityNagoya, Japan
| | - Chiyoko Machida
- Graduate School of Bioscience and Biotechnology, Chubu UniversityKasugai, Japan
| | - Yasunori Machida
- Division of Biological Science, Graduate School of Science, Nagoya UniversityNagoya, Japan
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Velázquez E, Palomo JL, Rivas R, Guerra H, Peix A, Trujillo ME, García-Benavides P, Mateos PF, Wabiko H, Martínez-Molina E. Analysis of core genes supports the reclassification of strains Agrobacterium radiobacter K84 and Agrobacterium tumefaciens AKE10 into the species Rhizobium rhizogenes. Syst Appl Microbiol 2010; 33:247-51. [PMID: 20627641 DOI: 10.1016/j.syapm.2010.04.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Revised: 04/17/2010] [Accepted: 04/20/2010] [Indexed: 11/18/2022]
Abstract
Some strains of the former genus Agrobacterium have high biotechnological interest and are currently misclassified. Consequently, in this study, the taxonomic status of the non-pathogenic strain Agrobacterium radiobacter K84, used in biological control, and the tumourigenic strain Agrobacterium tumefaciens AKE10, able to regenerate tobacco transgenic plants, was revised. The phylogenetic analysis of the chromosomal genes rrs, atpD and recA showed that they should be reclassified into Rhizobium rhizogenes. The analysis of virulence genes located in the Ti plasmid (pTi) outside T-DNA showed a common phylogenetic origin among strains AKE10, R. rhizogenes 163C and A. tumefaciens (currently R. radiobacter) C58. However, the genes located inside the T-DNA, mainly the 6b gene, of strain AKE10 were phylogenetically close to those of strain 163C but divergent from those of strain C58. Furthermore, the T-DNA of tumourigenic strains from R. rhizogenes conferred on them the ability to regenerate tumour tissue resembling fasciation in tobacco plants. These results showed the existence of a highly mosaic genetic organization in tumourigenic strains of the genus Rhizobium and provided evidence of the involvement of T-DNA from tumourigenic strains of R. rhizogenes in fasciation of Nicotiana leaves. The data further suggested that pathogenic strains of Rhizobium could be good models to analyse bacterial evolution.
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Affiliation(s)
- Encarna Velázquez
- Departamento de Microbiología y Genética, Edificio Departamental de Biología, Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain.
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Kleter GA, Peijnenburg AACM, Aarts HJM. Health considerations regarding horizontal transfer of microbial transgenes present in genetically modified crops. J Biomed Biotechnol 2010; 2005:326-52. [PMID: 16489267 PMCID: PMC1364539 DOI: 10.1155/jbb.2005.326] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The potential effects of horizontal gene transfer on human health
are an important item in the safety assessment of genetically
modified organisms. Horizontal gene transfer from genetically
modified crops to gut microflora most likely occurs with
transgenes of microbial origin. The characteristics of microbial
transgenes other than antibiotic-resistance genes in
market-approved genetically modified crops are reviewed. These
characteristics include the microbial source, natural function,
function in genetically modified crops, natural prevalence,
geographical distribution, similarity to other microbial genes,
known horizontal transfer activity, selective conditions and
environments for horizontally transferred genes, and potential
contribution to pathogenicity and virulence in humans and animals.
The assessment of this set of data for each of the microbial genes
reviewed does not give rise to health concerns. We recommend
including the above-mentioned items into the premarket safety
assessment of genetically modified crops carrying transgenes other
than those reviewed in the present study.
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Affiliation(s)
- Gijs A Kleter
- RIKILT, Institute of Food Safety, Wageningen University and Research Center, Wageningen, The Netherlands.
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16
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Kitakura S, Terakura S, Yoshioka Y, Machida C, Machida Y. Interaction between Agrobacterium tumefaciens oncoprotein 6b and a tobacco nucleolar protein that is homologous to TNP1 encoded by a transposable element of Antirrhinum majus. JOURNAL OF PLANT RESEARCH 2008; 121:425-33. [PMID: 18463947 DOI: 10.1007/s10265-008-0160-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2007] [Accepted: 03/12/2008] [Indexed: 05/26/2023]
Abstract
When gene 6b on the T-DNA of Agrobacterium tumefaciens is transferred to plant cells, its expression causes plant hormone-independent division of cells in in vitro culture and abnormal cell growth, which induces various morphological defects in 6b-expressing transgenic Arabidopsis thaliana and Nicotiana tabacum plants. Protein 6b localizes to the nuclei, a requirement for the abnormal cell growth, and binds to a tobacco nuclear protein called NtSIP1 and histone H3. In addition, 6b has histone chaperone-like activity in vitro and affects the expression of various plant genes, including cell division-related genes and meristem-related class 1 KNOX homeobox genes, in transgenic Arabidopsis. Here, we report that 6b binds to a newly identified protein NtSIP2, whose amino acid sequence is predicted to be 30% identical and 51% similar to that of the TNP1 protein encoded by the transposon Tam1 of Antirrhinum majus. Immunolocalization analysis using anti-T7 antibodies showed nucleolar localization of most of the T7 epitope-tagged NtSIP2 proteins. A similar analysis with the T7-tagged 6b protein also showed subnucleolar as well as nuclear localization of the 6b protein. These results suggest the involvement of 6b along with NtSIP2 in certain molecular processes in the nucleolus as well as the nucleoplasm.
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Affiliation(s)
- Saeko Kitakura
- College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan
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17
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Terakura S, Ueno Y, Tagami H, Kitakura S, Machida C, Wabiko H, Aiba H, Otten L, Tsukagoshi H, Nakamura K, Machida Y. An oncoprotein from the plant pathogen agrobacterium has histone chaperone-like activity. THE PLANT CELL 2007; 19:2855-65. [PMID: 17890376 PMCID: PMC2048699 DOI: 10.1105/tpc.106.049551] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2006] [Revised: 08/23/2007] [Accepted: 08/27/2007] [Indexed: 05/17/2023]
Abstract
Protein 6b, encoded by T-DNA from the pathogen Agrobacterium tumefaciens, stimulates the plant hormone-independent division of cells in culture in vitro and induces aberrant cell growth and the ectopic expression of various genes, including genes related to cell division and meristem-related class 1 KNOX homeobox genes, in 6b-expressing transgenic Arabidopsis thaliana and Nicotiana tabacum plants. Protein 6b is found in nuclei and binds to several plant nuclear proteins. Here, we report that 6b binds specifically to histone H3 in vitro but not to other core histones. Analysis by bimolecular fluorescence complementation revealed an interaction in vivo between 6b and histone H3. We recovered 6b from a chromatin fraction from 6b-expressing plant cells. A supercoiling assay and digestion with micrococcal nuclease indicated that 6b acts as a histone chaperone with the ability to mediate formation of nucleosomes in vitro. Mutant 6b, lacking the C-terminal region that is required for cell division-stimulating activity and interaction with histone H3, was deficient in histone chaperone activity. Our results suggest a relationship between alterations in nucleosome structure and the expression of growth-regulating genes on the one hand and the induction of aberrant cell proliferation on the other.
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Affiliation(s)
- Shinji Terakura
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi, Japan
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18
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Baron C, Domke N, Beinhofer M, Hapfelmeier S. Elevated temperature differentially affects virulence, VirB protein accumulation, and T-pilus formation in different Agrobacterium tumefaciens and Agrobacterium vitis strains. J Bacteriol 2001; 183:6852-61. [PMID: 11698374 PMCID: PMC95526 DOI: 10.1128/jb.183.23.6852-6861.2001] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
That gene transfer to plant cells is a temperature-sensitive process has been known for more than 50 years. Previous work indicated that this sensitivity results from the inability to assemble a functional T pilus required for T-DNA and protein transfer to recipient cells. The studies reported here extend these observations and more clearly define the molecular basis of this assembly and transfer defect. T-pilus assembly and virulence protein accumulation were monitored in Agrobacterium tumefaciens strain C58 at different temperatures ranging from 20 degrees C to growth-inhibitory 37 degrees C. Incubation at 28 degrees C but not at 26 degrees C strongly inhibited extracellular assembly of the major T-pilus component VirB2 as well as of pilus-associated protein VirB5, and the highest amounts of T pili were detected at 20 degrees C. Analysis of temperature effects on the cell-bound virulence machinery revealed three classes of virulence proteins. Whereas class I proteins (VirB2, VirB7, VirB9, and VirB10) were readily detected at 28 degrees C, class II proteins (VirB1, VirB4, VirB5, VirB6, VirB8, VirB11, VirD2, and VirE2) were only detected after cell growth below 26 degrees C. Significant levels of class III proteins (VirB3 and VirD4) were only detected at 20 degrees C and not at higher temperatures. Shift of virulence-induced agrobacteria from 20 to 28 or 37 degrees C had no immediate effect on cell-bound T pili or on stability of most virulence proteins. However, the temperature shift caused a rapid decrease in the amount of cell-bound VirB3 and VirD4, and VirB4 and VirB11 levels decreased next. To assess whether destabilization of virulence proteins constitutes a general phenomenon, levels of virulence proteins and of extracellular T pili were monitored in different A. tumefaciens and Agrobacterium vitis strains grown at 20 and 28 degrees C. Levels of many virulence proteins were strongly reduced at 28 degrees C compared to 20 degrees C, and T-pilus assembly did not occur in all strains except "temperature-resistant" Ach5 and Chry5. Virulence protein levels correlated well with bacterial virulence at elevated temperature, suggesting that degradation of a limited set of virulence proteins accounts for the temperature sensitivity of gene transfer to plants.
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Affiliation(s)
- C Baron
- Institut für Genetik und Mikrobiologie der Universität München, Lehrstuhl für Mikrobiologie, Maria-Ward-Strasse 1a, D-80638 Munich, Germany.
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19
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Abstract
By determination of the nucleotide sequence adjacent to the right border of T-DNA of the mikimopine-type Ri plasmid (pRi1724) in Agrobacterium rhizogenes, a new open reading frame (ORF) encoding 318 amino acids was found. A transcript of 1.35 kb derived from this ORF was observed in hairy roots of Ajuga reptans by northern blotting analysis. Including its own promoter and terminator, this ORF was isolated from the pRi1724 T-DNA and introduced into tobacco plants by the Agrobacterium-binary vector system. Since mikimopine, an opine and a stereoisomer of cucumopine, was accumulated in all organs of the transgenic tobacco plants, the new ORF was deduced to be the mikimopine synthase gene. For comparison, the nucleotide sequence of cucumopine synthase encoded on pRi2659 was also determined. No homology was found between mikimopine synthase and cucumopine synthase at the nucleotide, but partial homology was found at the amino acid level. Mikimopine synthase and cucumopine synthase produced by a protein expression system using E. coli catalyzed the synthesis of mikimopine and cucumopine from L-histidine and alpha-ketoglutaric acid, requiring NADH as a cofactor. These synthesized opines were identified by paper electrophoresis, TLC and HPLC analyses. The synthesized mikimopine or cucumopine could be degraded by A. rhizogenes strains harboring Ri plasmids encoding the respective catabolic enzyme.
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Affiliation(s)
- K Suzuki
- Center for Gene Science, Hiroshima University, 1-4-2, Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527, Japan
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20
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Ridé M, Ridé S, Petit A, Bollet C, Dessaux Y, Gardan L. Characterization of plasmid-borne and chromosome-encoded traits of Agrobacterium biovar 1, 2, and 3 strains from France. Appl Environ Microbiol 2000; 66:1818-25. [PMID: 10788345 PMCID: PMC101418 DOI: 10.1128/aem.66.5.1818-1825.2000] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We collected 111 Agrobacterium isolates from galls of various origins (most of them from France) and analyzed both their plasmid-borne and chromosome-encoded traits. Phenotypic analysis of these strains allowed their classification in three phena which exactly matched the delineation of biovars 1, 2, and 3. A fourth phenon was identified which comprises three atypical strains. The phenotypic analysis has also allowed us to identify 12 additional characteristics which could be used to identify the three biovars of Agrobacterium. Our results also suggest that biovar 1 and 2 represent distinct species. Analysis of plasmid-borne traits confirmed that tartrate utilization is a common feature of biovar 3 strains (now named Agrobacterium vitis) and of Agrobacterium grapevine strains in general. Among pathogenic strains of Agrobacterium, several exhibited unusual opine synthesis and degradation patterns, and one strain of biovar 3 induced tumors containing vitopine and a novel opine-like molecule derived from putrescine. We have named this compound ridéopine.
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Affiliation(s)
- M Ridé
- Unité de Pathologie Végétale et Phytobactériologie, INRA, 49071 Beaucouzé Cedex, France
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21
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Burr TJ, Otten L. CROWN GALL OF GRAPE: Biology and Disease Management. ANNUAL REVIEW OF PHYTOPATHOLOGY 1999; 37:53-80. [PMID: 11701817 DOI: 10.1146/annurev.phyto.37.1.53] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Not until 1973 was it reported that strains of Agrobacterium that cause crown gall disease of grape form a specific group (later characterized as Agrobacterium vitis). Tumorigenic and nontumorigenic A. vitis have since been isolated from infected and symptomless grapes worldwide. Research on the genetic makeup of A. vitis has led to an improved understanding of pathogen biology and bacterial evolution. In addition, the identification of significant gene sequences has facilitated the development of PCR and RFLP-based identification procedures that continue to improve the detection of A. vitis in plants and soil. Current control practices rely on the use of disease-resistant cultivars, cultural practices that minimize plant injury, and the production of pathogen-free vines. Promising future controls include employment of biological control agents and development of crown gall-resistant transgenic grapevines.
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Affiliation(s)
- Thomas J. Burr
- Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva, NY 14456
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22
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Schrammeijer B, Hemelaar J, Hooykaas PJ. The presence and characterization of a virF gene on Agrobacterium vitis Ti plasmids. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 1998; 11:429-33. [PMID: 9574510 DOI: 10.1094/mpmi.1998.11.5.429] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Octopine and nopaline strains of Agrobacterium tumefaciens differ in their ability to induce tumors on Nicotiana glauca. The presence of a virF locus on the octopine Ti plasmid makes N. glauca a host plant for these strains, indicating that the VirF protein is a host-range determinant. Here we show the presence of a virF locus not only on the Agrobacterium vitis octopine/cucumopine plasmids pTiAg57 and pTiTm4, but also on the nopaline Ti plasmids pTiAT1, pTiAT66a, and pTiAT66b. On the octopine Ti plasmids from A. tumefaciens the virF gene is located between the virE locus and the left border of the T-region. In contrast, the virF gene on Ti plasmids of A. vitis is located at the very left end of the vir-region near the virA locus. The virF gene of pTiAg57 has been sequenced and codes for a protein of 202 amino acids with a molecular mass of 22,280 Da. Comparison showed that the virF gene from A. vitis strain Ag57 is almost identical to that from A. tumefaciens octopine strains. The transcription of the pTiAg57 virF is inducible by the plant phenolic compound acetosyringone through the presence of a vir-box consensus sequence in its promoter region. The VirF protein from pTiAg57 can complement octopine A. tumefaciens strains deleted for virF as shown by tumor formation on N. glauca.
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Affiliation(s)
- B Schrammeijer
- Institute of Molecular Plant Sciences, Clusius Laboratory, Leiden University, The Netherlands
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23
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Otten L, De Ruffray P, de Lajudie P, Michot B. Sequence and characterisation of a ribosomal RNA operon from Agrobacterium vitis. MOLECULAR & GENERAL GENETICS : MGG 1996; 251:99-107. [PMID: 8628253 DOI: 10.1007/bf02174350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
One of the four ribosomal RNA operons (rrnA) from the Agrobacterium vitis vitopine strain S4 was sequenced, rrnA is most closely related to the rrn operons of Bradyrhizobium japonicum and Rhodobacter sphaeroides and carries an fMet-tRNA gene downstream of its 5S gene, as in the case of R. sphaeroides. The 16S rRNA sequence of S4 differs from the A. vitis K309 type strain sequence by only one nucleotide, in spite of the fact that S4 and K309 have very different Ti plasmids. The predicted secondary structure of the S4 23S rRNA shows several features that are specific for the alpha proteobacteria, and an unusual branched structure in the universal B8 stem. The 3' ends of the three other rrn copies of S4 were also cloned and sequenced. Sequence comparison delimits the 3' ends of the four repeats and defines two groups: rrnA/rrnB and rrnC/rrnD.
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MESH Headings
- Base Sequence
- Molecular Sequence Data
- Nucleic Acid Conformation
- Operon
- RNA, Bacterial/genetics
- RNA, Ribosomal/genetics
- RNA, Ribosomal, 16S/chemistry
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 23S/chemistry
- RNA, Ribosomal, 23S/genetics
- RNA, Transfer, Met/chemistry
- RNA, Transfer, Met/genetics
- Repetitive Sequences, Nucleic Acid
- Rhizobiaceae/genetics
- Rhizobium/genetics
- Rhodobacter sphaeroides/genetics
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- L Otten
- Institute of Plant Molecular Biology, CNRS, Strasbourg, France
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