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Vats S, Kumar V, Mandlik R, Patil G, Sonah H, Roy J, Sharma TR, Deshmukh R. Reference Guided De Novo Genome Assembly of Transformation Pliable Solanum lycopersicum cv. Pusa Ruby. Genes (Basel) 2023; 14:570. [PMID: 36980842 PMCID: PMC10047940 DOI: 10.3390/genes14030570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/17/2023] [Accepted: 02/22/2023] [Indexed: 03/02/2023] Open
Abstract
Solanum lycopersicum cv. Pusa Ruby (PR) is a superior tomato cultivar routinely used as a model tomato variety. Here, we report a reference-guided genome assembly for PR, covering 97.6% of the total single-copy genes in the solanales order. The PR genome contains 34,075 genes and 423,288 variants, out of which 127,131 are intragenic and 1232 are of high impact. The assembly was packaged according to PanSol guidelines (N50 = 60,396,827) with the largest scaffold measuring 85 megabases. The similarity of the PR genome assembly to Heinz1706, M82, and Fla.8924 was measured and the results suggest PR has the lowest affinity towards the hybrid Fla.8924. We then analyzed the regeneration efficiency of PR in comparison to another variety, Pusa Early Dwarf (PED). PR was found to have a high regeneration rate (45.51%) and therefore, we performed allele mining for genes associated with regeneration and found that only AGAMOUS-LIKE15 has a null mutation. Further, allele mining for fruit quality-related genes was also executed. The PR genome has an Ovate mutation leading to round fruit shape, causing economically undesirable fruit cracking. This genomic data can be potentially used for large scale crop improvement programs as well as functional annotation studies.
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Affiliation(s)
- Sanskriti Vats
- National Agri-Food Biotechnology Institute (NABI), Mohali 140306, Punjab, India
- Regional Centre for Biotechnology, Faridabad 121001, Haryana, India
| | - Virender Kumar
- National Agri-Food Biotechnology Institute (NABI), Mohali 140306, Punjab, India
- Regional Centre for Biotechnology, Faridabad 121001, Haryana, India
| | - Rushil Mandlik
- National Agri-Food Biotechnology Institute (NABI), Mohali 140306, Punjab, India
- Department of Biotechnology, Panjab University, Chandigarh 160014, Punjab, India
| | - Gunvant Patil
- Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79410, USA
| | - Humira Sonah
- National Agri-Food Biotechnology Institute (NABI), Mohali 140306, Punjab, India
| | - Joy Roy
- National Agri-Food Biotechnology Institute (NABI), Mohali 140306, Punjab, India
| | - Tilak Raj Sharma
- Department of Crop Science, Indian Council of Agriculture Research (ICAR), Krishi Bhavan, New Delhi 110001, Delhi, India
| | - Rupesh Deshmukh
- Department of Biotechnology, Central University of Haryana, Mahendragarh 123031, Haryana, India
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Ma X, Zhao X, Zhang H, Zhang Y, Sun S, Li Y, Long Z, Liu Y, Zhang X, Li R, Tan L, Jiang L, Zhu JK, Li L. MAG2 and MAL Regulate Vesicle Trafficking and Auxin Homeostasis With Functional Redundancy. FRONTIERS IN PLANT SCIENCE 2022; 13:849532. [PMID: 35371137 PMCID: PMC8966843 DOI: 10.3389/fpls.2022.849532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
Auxin is a central phytohormone and controls almost all aspects of plant development and stress response. Auxin homeostasis is coordinately regulated by biosynthesis, catabolism, transport, conjugation, and deposition. Endoplasmic reticulum (ER)-localized MAIGO2 (MAG2) complex mediates tethering of arriving vesicles to the ER membrane, and it is crucial for ER export trafficking. Despite important regulatory roles of MAG2 in vesicle trafficking, the mag2 mutant had mild developmental abnormalities. MAG2 has one homolog protein, MAG2-Like (MAL), and the mal-1 mutant also had slight developmental phenotypes. In order to investigate MAG2 and MAL regulatory function in plant development, we generated the mag2-1 mal-1 double mutant. As expected, the double mutant exhibited serious developmental defects and more alteration in stress response compared with single mutants and wild type. Proteomic analysis revealed that signaling, metabolism, and stress response in mag2-1 mal-1 were affected, especially membrane trafficking and auxin biosynthesis, signaling, and transport. Biochemical and cell biological analysis indicated that the mag2-1 mal-1 double mutant had more serious defects in vesicle transport than the mag2-1 and mal-1 single mutants. The auxin distribution and abundance of auxin transporters were altered significantly in the mag2-1 and mal-1 single mutants and mag2-1 mal-1 double mutant. Our findings suggest that MAG2 and MAL regulate plant development and auxin homeostasis by controlling membrane trafficking, with functional redundancy.
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Affiliation(s)
- Xiaohui Ma
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Xiaonan Zhao
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Hailong Zhang
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Yiming Zhang
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Shanwen Sun
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Ying Li
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Zhengbiao Long
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Yuqi Liu
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Xiaomeng Zhang
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
| | - Rongxia Li
- Shanghai Center for Plant Stress Biology, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Li Tan
- Shanghai Center for Plant Stress Biology, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lixi Jiang
- Institute of Crop Science, Zhejiang University, Hangzhou, China
| | - Jian-Kang Zhu
- Shanghai Center for Plant Stress Biology, Center of Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lixin Li
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, College of Life Sciences, Ministry of Education, Northeast Forestry University, Harbin, China
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Huang FC, Chi SF, Chien PR, Liu YT, Chang HN, Lin CS, Hwang HH. Arabidopsis RAB8A, RAB8B and RAB8D Proteins Interact with Several RTNLB Proteins and are Involved in the Agrobacterium tumefaciens Infection Process. PLANT & CELL PHYSIOLOGY 2021; 62:1572-1588. [PMID: 34255832 DOI: 10.1093/pcp/pcab112] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 07/01/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
Arabidopsis thaliana small GTP-binding proteins, AtRAB8s, associate with the endomembrane system and modulate tubulovesicular trafficking between compartments of the biosynthetic and endocytic pathways. There are five members in Arabidopsis, namely AtRAB8A-8E. Yeast two-hybrid assays, bimolecular fluorescence complementation assays and glutathione-S-transferase pull-down assays showed that RAB8A, 8B and 8D interacted with several membrane-associated reticulon-like (AtRTNLB) proteins in yeast, plant cells and in vitro. Furthermore, RAB8A, 8B and 8D proteins showed interactions with the Agrobacterium tumefaciens virulence protein, VirB2, a component of a type IV secretion system (T4SS). A. tumefaciens uses a T4SS to transfer T-DNA and Virulence proteins to plants, which causes crown gall disease in plants. The Arabidopsis rab8A, rab8B and rab8D single mutants showed decreased levels of Agrobacterium-mediated root and seedling transformation, while the RAB8A, 8B and 8D overexpression transgenic Arabidopsis plants were hypersusceptible to A. tumefaciens and Pseudomonas syringae infections. RAB8A-8E transcripts accumulated differently in roots, rosette leaves, cauline leaves, inflorescence and flowers of wild-type plants. In summary, RAB8A, 8B and 8D interacted with several RTNLB proteins and participated in A. tumefaciens and P. syringae infection processes.
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Affiliation(s)
- Fan-Chen Huang
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan
| | - Shin-Fei Chi
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan
| | - Pei-Ru Chien
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan
| | - Yin-Tzu Liu
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan
| | - Hsin-Nung Chang
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan
| | - Choun-Sea Lin
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Hau-Hsuan Hwang
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan
- Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung 402, Taiwan
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Brooks RL, Mistry CS, Dixon AM. Curvature sensing amphipathic helix in the C-terminus of RTNLB13 is conserved in all endoplasmic reticulum shaping reticulons in Arabidopsis thaliana. Sci Rep 2021; 11:6326. [PMID: 33737685 PMCID: PMC7973432 DOI: 10.1038/s41598-021-85866-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/05/2021] [Indexed: 11/24/2022] Open
Abstract
The reticulon family of integral membrane proteins are conserved across all eukaryotes and typically localize to the endoplasmic reticulum (ER), where they are involved in generating highly-curved tubules. We recently demonstrated that Reticulon-like protein B13 (RTNLB13) from Arabidopsis thaliana contains a curvature-responsive amphipathic helix (APH) important for the proteins' ability to induce curvature in the ER membrane, but incapable of generating curvature by itself. We suggested it acts as a feedback element, only folding/binding once a sufficient degree of curvature has been achieved, and stabilizes curvature without disrupting the bilayer. However, it remains unclear whether this is unique to RTNLB13 or is conserved across all reticulons-to date, experimental evidence has only been reported for two reticulons. Here we used biophysical methods to characterize a minimal library of putative APH peptides from across the 21 A. thaliana isoforms. We found that reticulons with the closest evolutionary relationship to RTNLB13 contain curvature-sensing APHs in the same location with sequence conservation. Our data reveal that a more distantly-related branch of reticulons developed a ~ 20-residue linker between the transmembrane domain and APH. This may facilitate functional flexibility as previous studies have linked these isoforms not only to ER remodeling but other cellular activities.
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Affiliation(s)
- Rhiannon L Brooks
- MAS Centre for Doctoral Training, University of Warwick, Coventry, CV4 7AL, UK
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | - Chandni S Mistry
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | - Ann M Dixon
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
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Thompson MG, Moore WM, Hummel NFC, Pearson AN, Barnum CR, Scheller HV, Shih PM. Agrobacterium tumefaciens: A Bacterium Primed for Synthetic Biology. BIODESIGN RESEARCH 2020; 2020:8189219. [PMID: 37849895 PMCID: PMC10530663 DOI: 10.34133/2020/8189219] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 04/26/2020] [Indexed: 10/19/2023] Open
Abstract
Agrobacterium tumefaciens is an important tool in plant biotechnology due to its natural ability to transfer DNA into the genomes of host plants. Genetic manipulations of A. tumefaciens have yielded considerable advances in increasing transformational efficiency in a number of plant species and cultivars. Moreover, there is overwhelming evidence that modulating the expression of various mediators of A. tumefaciens virulence can lead to more successful plant transformation; thus, the application of synthetic biology to enable targeted engineering of the bacterium may enable new opportunities for advancing plant biotechnology. In this review, we highlight engineering targets in both A. tumefaciens and plant hosts that could be exploited more effectively through precision genetic control to generate high-quality transformation events in a wider range of host plants. We then further discuss the current state of A. tumefaciens and plant engineering with regard to plant transformation and describe how future work may incorporate a rigorous synthetic biology approach to tailor strains of A. tumefaciens used in plant transformation.
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Affiliation(s)
- Mitchell G. Thompson
- Joint BioEnergy Institute, Emeryville, CA, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Plant Biology, University of California-Davis, Davis, CA, USA
| | - William M. Moore
- Joint BioEnergy Institute, Emeryville, CA, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Plant and Microbial Biology, University of California-Berkeley, Berkeley, CA, USA
| | - Niklas F. C. Hummel
- Joint BioEnergy Institute, Emeryville, CA, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Plant Biology, University of California-Davis, Davis, CA, USA
| | - Allison N. Pearson
- Joint BioEnergy Institute, Emeryville, CA, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Collin R. Barnum
- Department of Plant Biology, University of California-Davis, Davis, CA, USA
| | - Henrik V. Scheller
- Joint BioEnergy Institute, Emeryville, CA, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Plant and Microbial Biology, University of California-Berkeley, Berkeley, CA, USA
| | - Patrick M. Shih
- Joint BioEnergy Institute, Emeryville, CA, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Plant Biology, University of California-Davis, Davis, CA, USA
- Genome Center, University of California-Davis, Davis, CA, USA
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Orman-Ligeza B, Harwood W, Hedley PE, Hinchcliffe A, Macaulay M, Uauy C, Trafford K. TRA1: A Locus Responsible for Controlling Agrobacterium-Mediated Transformability in Barley. FRONTIERS IN PLANT SCIENCE 2020; 11:355. [PMID: 32373138 PMCID: PMC7176908 DOI: 10.3389/fpls.2020.00355] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/10/2020] [Indexed: 05/18/2023]
Abstract
In barley (Hordeum vulgare L.), Agrobacterium-mediated transformation efficiency is highly dependent on genotype with very few cultivars being amenable to transformation. Golden Promise is the cultivar most widely used for barley transformation and developing embryos are the most common donor tissue. We tested whether barley mutants with abnormally large embryos were more or less amenable to transformation and discovered that mutant M1460 had a transformation efficiency similar to that of Golden Promise. The large-embryo phenotype of M1460 is due to mutation at the LYS3 locus. There are three other barley lines with independent mutations at the same LYS3 locus, and one of these, Risø1508 has an identical missense mutation to that in M1460. However, none of the lys3 mutants except M1460 were transformable showing that the locus responsible for transformation efficiency, TRA1, was not LYS3 but another locus unique to M1460. To identify TRA1, we generated a segregating population by crossing M1460 to the cultivar Optic, which is recalcitrant to transformation. After four rounds of backcrossing to Optic, plants were genotyped and their progeny were tested for transformability. Some of the progeny lines were transformable at high efficiencies similar to those seen for the parent M1460 and some were not transformable, like Optic. A region on chromosome 2H inherited from M1460 is present in transformable lines only. We propose that one of the 225 genes in this region is TRA1.
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Affiliation(s)
- Beata Orman-Ligeza
- National Institute of Agricultural Botany (NIAB), Cambridge, United Kingdom
| | - Wendy Harwood
- John Innes Centre, Norwich Research Park, Norwich, United Kingdom
| | - Pete E. Hedley
- The James Hutton Institute, Invergowrie, Dundee, United Kingdom
| | | | | | - Cristobal Uauy
- John Innes Centre, Norwich Research Park, Norwich, United Kingdom
| | - Kay Trafford
- National Institute of Agricultural Botany (NIAB), Cambridge, United Kingdom
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Huang FC, Hwang HH. Arabidopsis RETICULON-LIKE4 (RTNLB4) Protein Participates in Agrobacterium Infection and VirB2 Peptide-Induced Plant Defense Response. Int J Mol Sci 2020; 21:ijms21051722. [PMID: 32138311 PMCID: PMC7084338 DOI: 10.3390/ijms21051722] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/28/2020] [Accepted: 02/29/2020] [Indexed: 12/27/2022] Open
Abstract
Agrobacterium tumefaciens uses the type IV secretion system, which consists of VirB1-B11 and VirD4 proteins, to deliver effectors into plant cells. The effectors manipulate plant proteins to assist in T-DNA transfer, integration, and expression in plant cells. The Arabidopsis reticulon-like (RTNLB) proteins are located in the endoplasmic reticulum and are involved in endomembrane trafficking in plant cells. The rtnlb4 mutants were recalcitrant to A. tumefaciens infection, but overexpression of RTNLB4 in transgenic plants resulted in hypersusceptibility to A. tumefaciens transformation, which suggests the involvement of RTNLB4 in A. tumefaciens infection. The expression of defense-related genes, including FRK1, PR1, WRKY22, and WRKY29, were less induced in RTNLB4 overexpression (O/E) transgenic plants after A. tumefaciens elf18 peptide treatment. Pretreatment with elf18 peptide decreased Agrobacterium-mediated transient expression efficiency more in wild-type seedlings than RTNLB4 O/E transgenic plants, which suggests that the induced defense responses in RTNLB4 O/E transgenic plants might be affected after bacterial elicitor treatments. Similarly, A. tumefaciens VirB2 peptide pretreatment reduced transient T-DNA expression in wild-type seedlings to a greater extent than in RTNLB4 O/E transgenic seedlings. Furthermore, the VirB2 peptides induced FRK1, WRKY22, and WRKY29 gene expression in wild-type seedlings but not efr-1 and bak1 mutants. The induced defense-related gene expression was lower in RTNLB4 O/E transgenic plants than wild-type seedlings after VirB2 peptide treatment. These data suggest that RTNLB4 may participate in elf18 and VirB2 peptide-induced defense responses and may therefore affect the A. tumefaciens infection process.
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Affiliation(s)
- Fan-Chen Huang
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan;
- Ph.D. Program in Microbial Genomics, National Chung Hsing University and Academia Sinica, Taichung 402, Taiwan
| | - Hau-Hsuan Hwang
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan;
- Ph.D. Program in Microbial Genomics, National Chung Hsing University and Academia Sinica, Taichung 402, Taiwan
- Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung 402, Taiwan
- Correspondence: ; Tel.: +886-4-2284-0416-412
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Huang FC, Fu BJ, Liu YT, Chang YR, Chi SF, Chien PR, Huang SC, Hwang HH. Correction: Huang, F.-C., et al. Arabidopsis RETICULON-LIKE3 (RTNLB3) and RTNLB8 Participate in Agrobacterium-Mediated Plant Transformation. Int. J. Mol. Sci. 2018, 19, 638. Int J Mol Sci 2019; 20:E664. [PMID: 30717486 PMCID: PMC6386870 DOI: 10.3390/ijms20030664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 02/02/2019] [Indexed: 11/16/2022] Open
Abstract
The authors would like to make a correction to their published paper [...].
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Affiliation(s)
- Fan-Chen Huang
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan.
- Ph.D. Program in Microbial Genomics, National Chung Hsing University and Academia Sinica, Taichung 402, Taiwan.
| | - Bi-Ju Fu
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan.
| | - Yin-Tzu Liu
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan.
| | - Yao-Ren Chang
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan.
| | - Shin-Fei Chi
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan.
| | - Pei-Ru Chien
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan.
| | - Si-Chi Huang
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan.
| | - Hau-Hsuan Hwang
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan.
- Ph.D. Program in Microbial Genomics, National Chung Hsing University, Taichung 402, Taiwan.
- Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan.
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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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