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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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2
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Recent Advances in Antibiotic-Free Markers; Novel Technologies to Enhance Safe Human Food Production in the World. Mol Biotechnol 2022:10.1007/s12033-022-00609-7. [DOI: 10.1007/s12033-022-00609-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/07/2022] [Indexed: 11/30/2022]
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3
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Aliu E, Lee K, Wang K. CRISPR RNA-guided integrase enables high-efficiency targeted genome engineering in Agrobacterium tumefaciens. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:1916-1927. [PMID: 35690588 PMCID: PMC9491456 DOI: 10.1111/pbi.13872] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/03/2022] [Accepted: 06/08/2022] [Indexed: 06/15/2023]
Abstract
Agrobacterium tumefaciens, the causal agent of plant crown gall disease, has been widely used to genetically transform many plant species. The inter-kingdom gene transfer capability made Agrobacterium an essential tool and model system to study the mechanism of exporting and integrating a segment of bacterial DNA into the plant genome. However, many biological processes such as Agrobacterium-host recognition and interaction are still elusive. To accelerate the understanding of this important plant pathogen and further improve its capacity in plant genetic engineering, we adopted a CRISPR RNA-guided integrase system for Agrobacterium genome engineering. In this work, we demonstrate that INsertion of Transposable Elements by Guide RNA-Assisted TargEting (INTEGRATE) can efficiently generate DNA insertions to enable targeted gene knockouts. In addition, in conjunction with Cre-loxP recombination system, we achieved precise deletions of large DNA fragments. This work provides new genetic engineering strategies for Agrobacterium species and their gene functional analyses.
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Affiliation(s)
- Ephraim Aliu
- Department of AgronomyIowa State UniversityAmesIowaUSA
- Crop Bioengineering CenterIowa State UniversityAmesIowaUSA
- Interdepartmental Plant Biology MajorIowa State UniversityAmesIowaUSA
| | - Keunsub Lee
- Department of AgronomyIowa State UniversityAmesIowaUSA
- Crop Bioengineering CenterIowa State UniversityAmesIowaUSA
| | - Kan Wang
- Department of AgronomyIowa State UniversityAmesIowaUSA
- Crop Bioengineering CenterIowa State UniversityAmesIowaUSA
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Lacroix B, Citovsky V. Genetic factors governing bacterial virulence and host plant susceptibility during Agrobacterium infection. ADVANCES IN GENETICS 2022; 110:1-29. [PMID: 37283660 PMCID: PMC10241481 DOI: 10.1016/bs.adgen.2022.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Several species of the Agrobacterium genus represent unique bacterial pathogens able to genetically transform plants, by transferring and integrating a segment of their own DNA (T-DNA, transferred DNA) in their host genome. Whereas in nature this process results in uncontrolled growth of the infected plant cells (tumors), this capability of Agrobacterium has been widely used as a crucial tool to generate transgenic plants, for research and biotechnology. The virulence of Agrobacterium relies on a series of virulence genes, mostly encoded on a large plasmid (Ti-plasmid, tumor inducing plasmid), involved in the different steps of the DNA transfer to the host cell genome: activation of bacterial virulence, synthesis and export of the T-DNA and its associated proteins, intracellular trafficking of the T-DNA and effector proteins in the host cell, and integration of the T-DNA in the host genomic DNA. Multiple interactions between these bacterial encoded proteins and host factors occur during the infection process, which determine the outcome of the infection. Here, we review our current knowledge of the mechanisms by which bacterial and plant factors control Agrobacterium virulence and host plant susceptibility.
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5
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Wang H, Zhang M, Xu Y, Zong R, Xu N, Guo M. Agrobacterium fabrum atu0526-Encoding Protein Is the Only Chemoreceptor That Regulates Chemoattraction toward the Broad Antibacterial Agent Formic Acid. BIOLOGY 2021; 10:biology10121345. [PMID: 34943260 PMCID: PMC8698456 DOI: 10.3390/biology10121345] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 12/11/2021] [Accepted: 12/13/2021] [Indexed: 12/25/2022]
Abstract
Soil-born plant pathogens, especially Agrobacterium, generally navigate their way to hosts through recognition of the root exudates by chemoreceptors. However, there is still a lack of appropriate identification of chemoreceptors and their ligands in Agrobacterium. Here, Atu0526, a sCache-type chemoreceptor from Agrobacterium fabrum C58, was confirmed as the receptor of a broad antibacterial agent, formic acid. The binding of formic acid to Atu0526 was screened using a thermo shift assay and verified using isothermal titration calorimetry. Inconsistent with the previously reported antimicrobial properties, formic acid was confirmed to be a chemoattractant to A. fabrum and could promote its growth. The chemotaxis of A. fabrum C58 toward formic acid was completely lost with the knock-out of atu0526, and regained with the complementation of the gene, indicating that Atu0526 is the only chemoreceptor for formic acid in A. fabrum C58. The affinity of formic acid to Atu0526LBD significantly increased after the arginine at position 115 was replaced by alanine. However, in vivo experiments showed that the R115A mutation fully abolished the chemotaxis of A. fabrum toward formic acid. Molecular docking based on a predicted 3D structure of Atu0526 suggested that the arginine may provide "an anchorage" for formic acid to pull the minor loop, thereby forming a conformational change that generates the ligand-binding signal. Collectively, our findings will promote an understanding of sCache-type chemoreceptors and their signal transduction mechanism.
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The Only Chemoreceptor Encoded by che Operon Affects the Chemotactic Response of Agrobacterium to Various Chemoeffectors. Microorganisms 2021; 9:microorganisms9091923. [PMID: 34576817 PMCID: PMC8466855 DOI: 10.3390/microorganisms9091923] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/02/2021] [Accepted: 09/07/2021] [Indexed: 12/16/2022] Open
Abstract
Chemoreceptor (also called methyl-accepting chemotaxis protein, MCP) is the leading signal protein in the chemotaxis signaling pathway. MCP senses and binds chemoeffectors, specifically, and transmits the sensed signal to downstream proteins of the chemotaxis signaling system. The genome of Agrobacterium fabrum (previously, tumefaciens) C58 predicts that a total of 20 genes can encode MCP, but only the MCP-encoding gene atu0514 is located inside the che operon. Hence, the identification of the exact function of atu0514-encoding chemoreceptor (here, named as MCP514) will be very important for us to understand more deeply the chemotaxis signal transduction mechanism of A. fabrum. The deletion of atu0514 significantly decreased the chemotactic migration of A. fabrum in a swim plate. The test of atu0514-deletion mutant (Δ514) chemotaxis toward single chemicals showed that the deficiency of MCP514 significantly weakened the chemotactic response of A. fabrum to four various chemicals, sucrose, valine, citric acid and acetosyringone (AS), but did not completely abolish the chemotactic response. MCP514 was localized at cell poles although it lacks a transmembrane (TM) region and is predicted to be a cytoplasmic chemoreceptor. The replacement of residue Phe328 showed that the helical structure in the hairpin subdomain of MCP514 is a direct determinant for the cellular localization of MCP514. Single respective replacements of key residues indicated that residues Asn336 and Val353 play a key role in maintaining the chemotactic function of MCP514.
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The Divergent Key Residues of Two Agrobacterium fabrum ( tumefaciens) CheY Paralogs Play a Key Role in Distinguishing Their Functions. Microorganisms 2021; 9:microorganisms9061134. [PMID: 34074050 PMCID: PMC8225110 DOI: 10.3390/microorganisms9061134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/21/2021] [Accepted: 05/22/2021] [Indexed: 11/23/2022] Open
Abstract
The chemotactic response regulator CheY, when phosphorylated by the phosphoryl group from phosphorylated CheA, can bind to the motor switch complex to control the flagellar motor rotation. Agrobacterium fabrum (previous name: Agrobacterium tumefaciens), a phytopathogen, carries two paralogous cheY genes, cheY1 and cheY2. The functional difference of two paralogous CheYs remains unclear. Three cheY-deletion mutants were constructed to test the effects of two CheYs on the chemotaxis of A.fabrum. Phenotypes of three cheY-deletion mutants show that deletion of each cheY significantly affects the chemotactic response, but cheY2-deletion possesses more prominent effects on the chemotactic migration and swimming pattern of A. fabrum than does cheY1-deletion. CheA-dependent cellular localization of two CheY paralogs and in vitro pull-down of two CheY paralogs by FliM demonstrate that the distinct roles of two CheY paralogs arise mainly from the differentiation of their binding affinities for the motor switch component FliM, agreeing with the divergence of the key residues on the motor-binding surface involved in the interaction with FliM. The single respective replacements of key residues R93 and A109 on the motor-binding surface of CheY2 by alanine (A) and valine (V), the corresponding residues of CheY1, significantly enhanced the function of CheY2 in regulating the chemotactic response of A. fabrum CheY-deficient mutant Δy to nutrient substances and host attractants. These results conclude that the divergence of the key residues in the functional subdomain is the decisive factor of functional differentiation of these two CheY homologs and protein function may be improved by the substitution of the divergent key residues in the functional domain for the corresponding residues of its paralogs. This finding will help us to better understand how paralogous proteins sub-functionalize. In addition, the acquirement of two CheY2 variants, whose chemotactic response functions are significantly improved, will be very useful for us to further explore the mechanism of CheY to bind and regulate the flagellar motor and the role of chemotaxis in the pathogenicity of A. fabrum.
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Yang J, Pan X, Xu Y, Li Y, Xu N, Huang Z, Ye J, Gao D, Guo M. Agrobacterium tumefaciens ferritins play an important role in full virulence through regulating iron homeostasis and oxidative stress survival. MOLECULAR PLANT PATHOLOGY 2020; 21:1167-1178. [PMID: 32678502 PMCID: PMC7411545 DOI: 10.1111/mpp.12969] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 06/06/2020] [Accepted: 06/08/2020] [Indexed: 05/23/2023]
Abstract
Ferritins are a large family of iron storage proteins, which are used by bacteria and other organisms to avoid iron toxicity and as a safe iron source in the cytosol. Agrobacterium tumefaciens, a phytopathogen, has two ferritin-encoding genes: atu2771 and atu2477. Atu2771 is annotated as a Bfr-encoding gene (Bacterioferritin, Bfr) and atu2477 as a Dps-encoding gene (DNA binding protein from starved cells, Dps). Three deletion mutants (Δbfr, Δdps, and bfr-dps double-deletion mutant ΔbdF) of these two ferritin-encoding genes were constructed to investigate the effects of ferritin deficiency on the iron homeostasis, oxidative stress resistance, and pathogenicity of A. tumefaciens. Deficiency of two ferritins affects the growth of A. tumefaciens under iron starvation and excess. When supplied with moderate iron, the growth of A. tumefaciens is not affected by the deficiency of ferritin. Deficiency of ferritin significantly reduces iron accumulation in the cells of A. tumefaciens, but the effect of Bfr deficiency on iron accumulation is severer than Dps deficiency and the double mutant ΔbdF has the least intracellular iron content. All three ferritin-deficient mutants showed a decreased tolerance to 3 mM H2 O2 in comparison with the wild type. The tumour induced by each of three ferritin-deficient mutants is less than that of the wild type. Complementation reversed the effects of ferritin deficiency on the growth, iron homeostasis, oxidative stress resistance, and tumorigenicity of A. tumefaciens. Therefore, ferritin plays an important role in the pathogenesis of A. tumefaciens through regulating iron homeostasis and oxidative stress survival.
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Affiliation(s)
- Jing Yang
- College of Bioscience and BiotechnologyYangzhou UniversityJiangsu ProvinceYangzhou CityChina
| | - Xiaoyue Pan
- College of Bioscience and BiotechnologyYangzhou UniversityJiangsu ProvinceYangzhou CityChina
| | - Yujuan Xu
- College of Bioscience and BiotechnologyYangzhou UniversityJiangsu ProvinceYangzhou CityChina
| | - Yuan Li
- College of Bioscience and BiotechnologyYangzhou UniversityJiangsu ProvinceYangzhou CityChina
| | - Nan Xu
- College of Bioscience and BiotechnologyYangzhou UniversityJiangsu ProvinceYangzhou CityChina
| | - Zhiwei Huang
- College of Bioscience and BiotechnologyYangzhou UniversityJiangsu ProvinceYangzhou CityChina
| | - Jingyang Ye
- College of Bioscience and BiotechnologyYangzhou UniversityJiangsu ProvinceYangzhou CityChina
| | - Dawei Gao
- College of Bioscience and BiotechnologyYangzhou UniversityJiangsu ProvinceYangzhou CityChina
| | - Minliang Guo
- College of Bioscience and BiotechnologyYangzhou UniversityJiangsu ProvinceYangzhou CityChina
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9
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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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Agrobacterium-mediated horizontal gene transfer: Mechanism, biotechnological application, potential risk and forestalling strategy. Biotechnol Adv 2018; 37:259-270. [PMID: 30579929 DOI: 10.1016/j.biotechadv.2018.12.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 12/18/2018] [Accepted: 12/18/2018] [Indexed: 11/20/2022]
Abstract
The extraordinary capacity of Agrobacterium to transfer its genetic material to host cell makes it evolve from phytopathogen to a powerful transgenic vector. Agrobacterium-mediated stable transformation is widely used as the preferred method to create transgenic plants for molecular plant biology research and crop breeding. Recent years, both mechanism and application of Agrobacterium-mediated horizontal gene transfer have made significant progresses, especially Agrobacterium-mediated transient transformation was developed for plant biotechnology industry to produce recombinant proteins. Agrobacterium strains are almost used and saved not only by each of microbiology and molecular plant labs, but also by many of plant biotechnology manufacturers. Agrobacterium is able to transfer its genetic material to a broad range of hosts, including plant and non-plant hosts. As a consequence, the concern of environmental risk associated with the accidental release of genetically modified Agrobacterium arises. In this article, we outline the recent progress in the molecular mechanism of Agrobacterium-meditated gene transfer, focus on the application of Agrobacterium-mediated horizontal gene transfer, and review the potential risk associated with Agrobacterium-meditated gene transfer. Based on the comparison between the infecting process of Agrobacterium as a pathogen and the transgenic process of Agrobacterium as a transgenic vector, we realize that chemotaxis is the distinct difference between these two biological processes and thus discuss the possible role of chemotaxis in forestalling the potential risk of Agrobacterium-meditated horizontal gene transfer to non-target plant species.
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Mary C, Baron C. Bases moléculaires de l’infection de plantes parAgrobacterium tumefaciensvia un système de sécrétion de type IV. Biochem Cell Biol 2018; 97:215-223. [PMID: 30142282 DOI: 10.1139/bcb-2018-0160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Agrobacterium tumefaciens is a well studied phytopathogen given its various applications for deciphering host-pathogen interactions, bacterial communication, and capacity to transfer DNA fragments into host cells via a membrane protein system, the type IV secretion system (T4SS). T4SS mechanism is similar to the one responsible for antibiotic resistance gene transmission, and new knowledge gained could be applied to other organisms using such a mechanism. As well, A. tumefaciens is of economic importance in biotechnology due to its capacity to generate genetically modified plants. Agrobacterium tumefaciens harbours a plasmid known as Ti plasmid encoding T4SS function genes used for transferring genetic information and plant colonization. In this review, the authors describe the molecular basis of infection, from detection of host signals, to the description of different regions of Ti plasmid key to infection, ending with substrate transfer through bacterial wall. [Journal translation].
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Affiliation(s)
- Charline Mary
- Département de biochimie et médecine moléculaire, Faculté de médecine, Université de Montréal, Montréal, QC H3C 3J7, Canada.,Département de biochimie et médecine moléculaire, Faculté de médecine, Université de Montréal, Montréal, QC H3C 3J7, Canada
| | - Christian Baron
- Département de biochimie et médecine moléculaire, Faculté de médecine, Université de Montréal, Montréal, QC H3C 3J7, Canada.,Département de biochimie et médecine moléculaire, Faculté de médecine, Université de Montréal, Montréal, QC H3C 3J7, Canada
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Huang Z, Zhou Q, Sun P, Yang J, Guo M. Two Agrobacterium tumefaciens CheW Proteins Are Incorporated into One Chemosensory Pathway with Different Efficiencies. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:460-470. [PMID: 29182466 DOI: 10.1094/mpmi-10-17-0255-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Agrobacterium tumefaciens is the agent that causes crown gall tumor disease on more than 140 species of dicotyledonous plants. Chemotaxis of A. tumefaciens toward the wound sites of the host plant is the first step to recognize the host. CheW is a coupling protein that bridges the histidine kinase CheA and the chemoreceptors to form the chemotaxis core signaling complex and plays a crucial role in the assembly and function of the large chemosensory array. Unlike all previously reported chemotaxis systems, A. tumefaciens has only one major che operon but two cheW homologs (atu2075 as cheW1 and atu2617 as cheW2) on unlinked loci. The in-frame deletion of either cheW gene significantly affects A. tumefaciens chemotaxis but does not abolish the chemotaxis, unless both cheW genes were deleted. The effect of cheW2 deletion on the chemotaxis is more severe than that of cheW1 deletion. Either CheW can interact with CheA and couple it to the cell poles. The promoter activity of cheW2 is always higher than that of cheW1 under all of the tested conditions. When two cheW genes were adjusted to the same expression level by using the identical promoter, the difference between the effects of two CheW proteins on the chemotaxis still existed. Therefore, we envision that both the different molecular ratio of two CheW proteins in cell and the different affinities of two CheW proteins with CheA and chemoreceptors result in the efficiency difference of two CheW proteins in functioning in the large chemosensory array.
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Affiliation(s)
- Zhiwei Huang
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou City, Jiangsu 225009, P R China
| | - Qingxuan Zhou
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou City, Jiangsu 225009, P R China
| | - Pan Sun
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou City, Jiangsu 225009, P R China
| | - Jing Yang
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou City, Jiangsu 225009, P R China
| | - Minliang Guo
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou City, Jiangsu 225009, P R China
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Li YG, Christie PJ. The Agrobacterium VirB/VirD4 T4SS: Mechanism and Architecture Defined Through In Vivo Mutagenesis and Chimeric Systems. Curr Top Microbiol Immunol 2018; 418:233-260. [PMID: 29808338 DOI: 10.1007/82_2018_94] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The Agrobacterium tumefaciens VirB/VirD4 translocation machine is a member of a superfamily of translocators designated as type IV secretion systems (T4SSs) that function in many species of gram-negative and gram-positive bacteria. T4SSs evolved from ancestral conjugation systems for specialized purposes relating to bacterial colonization or infection. A. tumefaciens employs the VirB/VirD4 T4SS to deliver oncogenic DNA (T-DNA) and effector proteins to plant cells, causing the tumorous disease called crown gall. This T4SS elaborates both a cell-envelope-spanning channel and an extracellular pilus for establishing target cell contacts. Recent mechanistic and structural studies of the VirB/VirD4 T4SS and related conjugation systems in Escherichia coli have defined T4SS architectures, bases for substrate recruitment, the translocation route for DNA substrates, and steps in the pilus biogenesis pathway. In this review, we provide a brief history of A. tumefaciens VirB/VirD4 T4SS from its discovery in the 1980s to its current status as a paradigm for the T4SS superfamily. We discuss key advancements in defining VirB/VirD4 T4SS function and structure, and we highlight the power of in vivo mutational analyses and chimeric systems for identifying mechanistic themes and specialized adaptations of this fascinating nanomachine.
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Affiliation(s)
- Yang Grace Li
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA
| | - Peter J Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA.
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Hwang HH, Yu M, Lai EM. Agrobacterium-mediated plant transformation: biology and applications. THE ARABIDOPSIS BOOK 2017; 15:e0186. [PMID: 31068763 PMCID: PMC6501860 DOI: 10.1199/tab.0186] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Plant genetic transformation heavily relies on the bacterial pathogen Agrobacterium tumefaciens as a powerful tool to deliver genes of interest into a host plant. Inside the plant nucleus, the transferred DNA is capable of integrating into the plant genome for inheritance to the next generation (i.e. stable transformation). Alternatively, the foreign DNA can transiently remain in the nucleus without integrating into the genome but still be transcribed to produce desirable gene products (i.e. transient transformation). From the discovery of A. tumefaciens to its wide application in plant biotechnology, numerous aspects of the interaction between A. tumefaciens and plants have been elucidated. This article aims to provide a comprehensive review of the biology and the applications of Agrobacterium-mediated plant transformation, which may be useful for both microbiologists and plant biologists who desire a better understanding of plant transformation, protein expression in plants, and plant-microbe interaction.
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Affiliation(s)
- Hau-Hsuan Hwang
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, 402
| | - Manda Yu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, 115
| | - Erh-Min Lai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, 115
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15
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Volokhina I, Gusev Y, Mazilov S, Moiseeva Y, Chumakov M. Computer evaluation of VirE2 protein complexes for ssDNA transfer ability. Comput Biol Chem 2017; 68:64-70. [DOI: 10.1016/j.compbiolchem.2017.01.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 01/23/2017] [Accepted: 01/23/2017] [Indexed: 11/16/2022]
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16
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Guo M, Huang Z, Yang J. Is there any crosstalk between the chemotaxis and virulence induction signaling in Agrobacterium tumefaciens? Biotechnol Adv 2017; 35:505-511. [PMID: 28342941 DOI: 10.1016/j.biotechadv.2017.03.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Revised: 03/17/2017] [Accepted: 03/22/2017] [Indexed: 12/25/2022]
Abstract
Agrobacterium tumefaciens, a soil-born phytopathogenic bacterium, is well known as a nature's engineer due to its ability to genetically transform the host by transferring a DNA fragment (called T-DNA) from its Ti plasmid to host-cell genome. To combat the harsh soil environment and seek the appropriate host, A. tumefaciens can sense and be attracted by a large number of chemical compounds released by wounded host. As a member of α-proteobacterium, A. tumefaciens has a chemotaxis system different from that found in Escherichia coli, since many chemoattractants for A. tumefaciens chemotaxis are virulence (vir) inducers. However, advances in the study of the chemotaxis paradigm, E. coli chemotaxis system, have provided enough information to analyze the A. tumefaciens chemotaxis. At low concentration, chemoattractants elicit A. tumefaciens chemotaxis and attract the species to the wound sites of the host. At high concentration, chemoattractants induce the expression of virulence genes and trigger T-DNA transfer. Recent studies on the VirA and ChvE of the vir-induction system provide some evidences to support the crosstalk between chemotaxis and vir-induction. This review compares the core components of chemotaxis signaling system of A. tumefaciens with those observed in other species, discusses the connection between chemotaxis and vir-induction in A. tumefaciens, and proposes a model depicting the signaling crosstalk between chemotaxis and vir-induction.
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Affiliation(s)
- Minliang Guo
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, Jiangsu 225009, China.
| | - Zhiwei Huang
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, Jiangsu 225009, China
| | - Jing Yang
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, Jiangsu 225009, China
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Yang J, Wu M, Zhang X, Guo M, Huang Z. Expression of Agrobacterium Homolog Genes Encoding T-complex Recruiting Protein under Virulence Induction Conditions. Front Microbiol 2015; 6:1379. [PMID: 26696988 PMCID: PMC4667095 DOI: 10.3389/fmicb.2015.01379] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 11/20/2015] [Indexed: 12/02/2022] Open
Abstract
The proteins encoded by three Agrobacterial genes, atu5117, atu4860, and atu4856, are highly homologous to each other in amino acid sequence. All three proteins can bind to VirD2 and are named VBP1, VBP2, and VBP3 (VirD2-binding protein), respectively. VBP is involved in T-DNA transfer by recruiting the T-complex from the cytosol to the polar transport apparatus T4SS (type IVsecretion system) and is defined as the “T-complex recruiting protein.” However, it remains unknown how these three homologous genes co-exist in a relatively small prokaryotic genome. To understand whether these three homologous genes are expressed differentially under virulence induction conditions, we examined the effects of virulence induction conditions, including various pH values, temperatures and acetosyringone (AS, an effective virulence inducer to Agrobacterium tumefaciens) concentrations, on the expression of the three VBP-encoding genes. Our data showed that vbp1 (atu5117) and vbp3 (atu4856) maintained constant expression under the tested induction conditions, whereas the expression of vbp2 (atu4860) was affected by the conditions. Culture conditions favorable to the expression of vbp2 differed from the reported induction conditions for other virulence proteins. In particular, the pH value was a crucial factor for the expression of vbp2. In addition, the deletion of vbp1 affected the expression of vbp2. Taken together, these results suggest that the mechanisms regulating the expression of these three homologous genes are different from the virulence induction mechanism and that VBP homologs are presumably involved in other biological processes in addition to T-complex recruitment.
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Affiliation(s)
- Jing Yang
- College of Bioscience and Biotechnology, Yangzhou University Yangzhou, China
| | - Meixia Wu
- College of Bioscience and Biotechnology, Yangzhou University Yangzhou, China
| | - Xin Zhang
- College of Bioscience and Biotechnology, Yangzhou University Yangzhou, China
| | - Minliang Guo
- College of Bioscience and Biotechnology, Yangzhou University Yangzhou, China
| | - Zhiwei Huang
- College of Bioscience and Biotechnology, Yangzhou University Yangzhou, China
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18
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Krenek P, Samajova O, Luptovciak I, Doskocilova A, Komis G, Samaj J. Transient plant transformation mediated by Agrobacterium tumefaciens: Principles, methods and applications. Biotechnol Adv 2015; 33:1024-42. [PMID: 25819757 DOI: 10.1016/j.biotechadv.2015.03.012] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 03/05/2015] [Accepted: 03/19/2015] [Indexed: 12/20/2022]
Abstract
Agrobacterium tumefaciens is widely used as a versatile tool for development of stably transformed model plants and crops. However, the development of Agrobacterium based transient plant transformation methods attracted substantial attention in recent years. Transient transformation methods offer several applications advancing stable transformations such as rapid and scalable recombinant protein production and in planta functional genomics studies. Herein, we highlight Agrobacterium and plant genetics factors affecting transfer of T-DNA from Agrobacterium into the plant cell nucleus and subsequent transient transgene expression. We also review recent methods concerning Agrobacterium mediated transient transformation of model plants and crops and outline key physical, physiological and genetic factors leading to their successful establishment. Of interest are especially Agrobacterium based reverse genetics studies in economically important crops relying on use of RNA interference (RNAi) or virus-induced gene silencing (VIGS) technology. The applications of Agrobacterium based transient plant transformation technology in biotech industry are presented in thorough detail. These involve production of recombinant proteins (plantibodies, vaccines and therapeutics) and effectoromics-assisted breeding of late blight resistance in potato. In addition, we also discuss biotechnological potential of recombinant GFP technology and present own examples of successful Agrobacterium mediated transient plant transformations.
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Affiliation(s)
- Pavel Krenek
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic.
| | - Olga Samajova
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic.
| | - Ivan Luptovciak
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic.
| | - Anna Doskocilova
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic.
| | - George Komis
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic.
| | - Jozef Samaj
- Centre of the Region Haná for Biotechnological and Agricultural Research, Department of Cell Biology, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71 Olomouc, Czech Republic.
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Wolterink-van Loo S, Ayala AAE, Hooykaas PJJ, van Heusden GPH. Interaction of the Agrobacterium tumefaciens virulence protein VirD2 with histones. MICROBIOLOGY-SGM 2014; 161:401-410. [PMID: 25505187 DOI: 10.1099/mic.0.083410-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Agrobacterium tumefaciens is a Gram-negative soil bacterium that genetically transforms plants and, under laboratory conditions, also transforms non-plant organisms, such as fungi and yeasts. During the transformation process a piece of ssDNA (T-strand) is transferred into the host cells via a type IV secretion system. The VirD2 relaxase protein, which is covalently attached at the 5' end of the T-strand through Tyr29, mediates nuclear entry as it contains a nuclear localization sequence. How the T-strand reaches the chromatin and becomes integrated in the chromosomal DNA is still far from clear. Here, we investigated whether VirD2 binds to histone proteins in the yeast Saccharomyces cerevisiae. Using immobilized GFP-VirD2 and in vitro synthesized His6-tagged S. cerevisiae proteins, interactions between VirD2 and the histones H2A, H2B, H3 and H4 were revealed. In vivo, these interactions were confirmed by bimolecular fluorescence complementation experiments. After co-cultivation of Agrobacterium strains expressing VirD2 tagged with a fragment of the yellow fluorescent protein analogue Venus with yeast strains expressing histone H2A or H2B tagged with the complementary part of Venus, fluorescence was detected in dot-shaped structures in the recipient yeast cells. The results indicated that VirD2 was transferred from Agrobacterium to yeast cells and that it interacted with histones in the host cell, and thus may help direct the T-DNA (transferred DNA) to the chromatin as a prelude to integration into the host chromosomal DNA.
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Affiliation(s)
- Suzanne Wolterink-van Loo
- Section Molecular and Developmental Genetics, Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Abril A Escamilla Ayala
- Section Molecular and Developmental Genetics, Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Paul J J Hooykaas
- Section Molecular and Developmental Genetics, Institute of Biology, Leiden University, Leiden, The Netherlands
| | - G Paul H van Heusden
- Section Molecular and Developmental Genetics, Institute of Biology, Leiden University, Leiden, The Netherlands
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Padavannil A, Jobichen C, Qinghua Y, Seetharaman J, Velazquez-Campoy A, Yang L, Pan SQ, Sivaraman J. Dimerization of VirD2 binding protein is essential for Agrobacterium induced tumor formation in plants. PLoS Pathog 2014; 10:e1003948. [PMID: 24626239 PMCID: PMC3953389 DOI: 10.1371/journal.ppat.1003948] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 01/09/2014] [Indexed: 01/07/2023] Open
Abstract
The Type IV Secretion System (T4SS) is the only bacterial secretion system known to translocate both DNA and protein substrates. The VirB/D4 system from Agrobacterium tumefaciens is a typical T4SS. It facilitates the bacteria to translocate the VirD2-T-DNA complex to the host cell cytoplasm. In addition to protein-DNA complexes, the VirB/D4 system is also involved in the translocation of several effector proteins, including VirE2, VirE3 and VirF into the host cell cytoplasm. These effector proteins aid in the proper integration of the translocated DNA into the host genome. The VirD2-binding protein (VBP) is a key cytoplasmic protein that recruits the VirD2-T-DNA complex to the VirD4-coupling protein (VirD4 CP) of the VirB/D4 T4SS apparatus. Here, we report the crystal structure and associated functional studies of the C-terminal domain of VBP. This domain mainly consists of α-helices, and the two monomers of the asymmetric unit form a tight dimer. The structural analysis of this domain confirms the presence of a HEPN (higher eukaryotes and prokaryotes nucleotide-binding) fold. Biophysical studies show that VBP is a dimer in solution and that the HEPN domain is the dimerization domain. Based on structural and mutagenesis analyses, we show that substitution of key residues at the interface disrupts the dimerization of both the HEPN domain and full-length VBP. In addition, pull-down analyses show that only dimeric VBP can interact with VirD2 and VirD4 CP. Finally, we show that only Agrobacterium harboring dimeric full-length VBP can induce tumors in plants. This study sheds light on the structural basis of the substrate recruiting function of VBP in the T4SS pathway of A. tumefaciens and in other pathogenic bacteria employing similar systems.
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Affiliation(s)
- Abhilash Padavannil
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Chacko Jobichen
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Yang Qinghua
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Jayaraman Seetharaman
- X4 Beamline, Brookhaven National Laboratory, Upton, New York, United States of America
| | - Adrian Velazquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint-Unit IQFR-CSIC-BIFI, and Department of Biochemistry and Molecular and Cell Biology, University of Zaragoza, Zaragoza, Spain, and Fundacion ARAID, Government of Aragon, Zaragoza, Spain
| | - Liu Yang
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Shen Q. Pan
- Department of Biological Sciences, National University of Singapore, Singapore
| | - J. Sivaraman
- Department of Biological Sciences, National University of Singapore, Singapore
- * E-mail:
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Gao D, Bian X, Guo M, Wang J, Zhang X. Identification and characterization of the biochemical function of Agrobacterium T-complex-recruiting protein Atu5117. FEBS J 2013; 280:4865-75. [PMID: 23902381 DOI: 10.1111/febs.12460] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Revised: 07/24/2013] [Accepted: 07/26/2013] [Indexed: 01/19/2023]
Abstract
Atu5117 from Agrobacterium tumefaciens is a highly conserved protein with a putative nucleotidyltransferase domain in its N-terminal region and a putative higher eukaryotes and prokaryotes nucleotide-binding domain in its C-terminal region. This protein has been shown to be a T-complex-recruiting protein that can recruit T-complex from the cytosol to the polar VirB/D4 type IV secretion system (T4SS). However, the biochemical function of Atu5117 is still unknown. Here, we show that Atu5117 is a (d)NTPase. Although no proteins with nucleotidyltransferase and higher eukaryotes and prokaryotes nucleotide-binding domains were identified as (d)NTPases, Atu5117 was able to convert all eight canonical NTPs and dNTPs to NDP, dNDP and inorganic phosphate in vitro, and required Mg(2+) for its (d)NTPase activity. The kinetic parameters of Atu5117 (d)NTPase for eight substrates were characterized. Kinetic data showed that Atu5117 (d)NTPase preferred ATP as its substrate. The optimal conditions for (d)NTPase activity of Atu5117 were very similar to those required for Agrobacterium tumorigenesis. The kinetic parameters of (d)NTPase of Atu5117 for all four canonical NTPs were in the same orders of magnitude as the kinetic parameters of the ATPases identified in some components of the VirB/D4 T4SS. These results suggest that Atu5117 might function as an energizer to recruit T-complex to the T4SS transport site.
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Affiliation(s)
- Diankun Gao
- College of Bioscience and Biotechnology, Yangzhou University, China
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22
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Development and Optimization of Method for Generating Unmarked A. tumefaciens Mutants*. PROG BIOCHEM BIOPHYS 2009. [DOI: 10.3724/sp.j.1206.2008.00618] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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23
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van Kregten M, Lindhout BI, Hooykaas PJJ, van der Zaal BJ. Agrobacterium-mediated T-DNA transfer and integration by minimal VirD2 consisting of the relaxase domain and a type IV secretion system translocation signal. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2009; 22:1356-1365. [PMID: 19810805 DOI: 10.1094/mpmi-22-11-1356] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The VirD2 protein of Agrobacterium tumefaciens is essential for processing and transport of the T-DNA. It has at least three functional domains: a relaxase domain at the N terminus, a bipartite nuclear localization signal (NLS), and a sequence called omega at the C terminus. We confirm here that deletions of the C-terminal part of VirD2 led to lack of transfer of T-DNA but, for the first time, we report that virulence is restored when these truncations are supplemented at the C terminus by a short translocation signal from the VirF protein. The lack of virulence of C-terminal deletions suggests that the C-terminal part contains all or part of the translocation signal of VirD2. Using a novel series of mutant VirD2 proteins, the C-terminal half of VirD2 was further investigated. We demonstrate that the C-terminal 40 amino acids of VirD2, which include the NLS and omega, contain all or part of the translocation domain necessary for transport of VirD2 into plant cells, while another element is present in the middle of the protein. The finding that a type IV secretion system transport signal at the C terminus of VirD2 is necessary for virulence provides evidence for the role of VirD2 as a pilot protein driving translocation of the T-strand.
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Affiliation(s)
- Maartje van Kregten
- Clusius Laboratory, Department of Molecular and Developmental Genetics, Institute of Biology Leiden, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands
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Recruitment of conjugative DNA transfer substrate to Agrobacterium type IV secretion apparatus. Proc Natl Acad Sci U S A 2007; 104:20019-24. [PMID: 18056647 DOI: 10.1073/pnas.0701738104] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacterial type IV secretion system (T4SS) belongs to a growing class of evolutionarily conserved transporters that translocate DNA and proteins into a wide variety of organisms including bacterial and eukaryotic cells. Archetypal is the Agrobacterium tumefaciens VirB/D4 T4SS that transfers oncogenic T-DNA to various eukaryotic cells, which is transferred as a nucleoprotein T-complex with VirD2 as the pilot protein. As a derivative of plasmid conjugation systems, the VirB/D4 T4SS can also transfer certain mobilizable plasmids and bacterial proteins like VirE2 and VirF, although it is unknown how the membrane-bound T4SS recruits different transfer substrates. Here, we show that a cytoplasmic VirD2-binding protein (VBP) is involved in the recruitment of the T-complex to the energizing components of the T4SS, including VirD4, VirB4, and VirB11. VBP is also important for the recruitment of a conjugative plasmid to a different transfer system independent of VirB/D4. These data indicate that VBP functions as a previously unrecognized recruiting protein that helps couple nucleoprotein substrates to the appropriate transport sites for conjugative DNA transfers. VBP has three functionally redundant homologs, and similar homologs can be found in different bacterial genomes, suggesting a previously uncharacterized class of proteins involved in conjugative DNA transfers.
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