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Revealing the Complexity of Sweepovirus-Deltasatellite-Plant Host Interactions: Expanded Natural and Experimental Helper Virus Range and Effect Dependence on Virus-Host Combination. Microorganisms 2021; 9:microorganisms9051018. [PMID: 34068583 PMCID: PMC8150397 DOI: 10.3390/microorganisms9051018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/06/2021] [Accepted: 05/07/2021] [Indexed: 11/16/2022] Open
Abstract
Sweepoviruses are begomoviruses (genus Begomovirus, family Geminiviridae) with ssDNA genomes infecting sweet potato and other species of the family Convolvulaceae. Deltasatellites (genus Deltasatellite, family Tolecusatellitidae) are small-size non-coding DNA satellites associated with begomoviruses. In this study, the genetic diversity of deltasatellites associated with sweepoviruses infecting Ipomoea indica plants was analyzed by further sampling the populations where the deltasatellite sweet potato leaf curl deltasatellite 1 (SPLCD1) was initially found, expanding the search to other geographical areas in southern continental Spain and the Canary Islands. The sweepoviruses present in the samples coinfected with deltasatellites were also fully characterized by sequencing in order to define the range of viruses that could act as helper viruses in nature. Additionally, experiments were performed to assess the ability of a number of geminivirids (the monopartite tomato leaf deformation virus and the bipartite NW begomovirus Sida golden yellow vein virus, the bipartite OW begomovirus tomato leaf curl New Delhi virus, and the curtovirus beet curly top virus) to transreplicate SPLCD1 in their natural plant hosts or the experimental host Nicotiana benthamiana. The results show that SPLCD1 can be transreplicated by all the geminivirids assayed in N. benthamiana and by tomato leaf curl New Delhi virus in zucchini. The presence of SPLCD1 did not affect the symptomatology caused by the helper viruses, and its effect on viral DNA accumulation depended on the helper virus-host plant combination.
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Fiallo-Olivé E, Trenado HP, Louro D, Navas-Castillo J. Recurrent speciation of a tomato yellow leaf curl geminivirus in Portugal by recombination. Sci Rep 2019; 9:1332. [PMID: 30718735 PMCID: PMC6362282 DOI: 10.1038/s41598-018-37971-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 12/18/2018] [Indexed: 11/09/2022] Open
Abstract
Recurrent evolution can involve interspecific interactions, recognized to play a primary role in the diversification and organization of life. Both in the plant and animal kingdoms, the recurrent formation of allopolyploid species has been described. In the virosphere, recombination between isolates of different species has been shown to be a source of speciation. In this work, complete genome analysis showed that speciation through recombination of an emergent DNA plant virus, tomato yellow leaf curl Malaga virus (genus Begomovirus, family Geminiviridae), has occurred independently in Portugal and Spain, confirming previous observations with tomato yellow leaf curl Axarquia virus, also originated independently in Spain and Italy. These results will guide future research to discover new cases of recurrent emergence of recombinant virus species in geographical areas where the putative parents co-exist or can be introduced. This will reveal the role that recurrent speciation through recombination plays in the evolution of the virosphere and will help to understand the consequences of this phenomenon on the diversification of life.
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Affiliation(s)
- Elvira Fiallo-Olivé
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Consejo Superior de Investigaciones Científicas - Universidad de Málaga (IHSM-CSIC-UMA), Avenida Dr. Wienberg s/n, 29750, Algarrobo-Costa, Málaga, Spain
| | - Helena P Trenado
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Consejo Superior de Investigaciones Científicas - Universidad de Málaga (IHSM-CSIC-UMA), Avenida Dr. Wienberg s/n, 29750, Algarrobo-Costa, Málaga, Spain
| | - Diamantina Louro
- Instituto Nacional dos Recursos Biológicos (INRB), Quinta do Marquês, Oeiras, Portugal
| | - Jesús Navas-Castillo
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora", Consejo Superior de Investigaciones Científicas - Universidad de Málaga (IHSM-CSIC-UMA), Avenida Dr. Wienberg s/n, 29750, Algarrobo-Costa, Málaga, Spain.
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Arenas M, Araujo NM, Branco C, Castelhano N, Castro-Nallar E, Pérez-Losada M. Mutation and recombination in pathogen evolution: Relevance, methods and controversies. INFECTION GENETICS AND EVOLUTION 2017; 63:295-306. [PMID: 28951202 DOI: 10.1016/j.meegid.2017.09.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 09/20/2017] [Accepted: 09/21/2017] [Indexed: 02/06/2023]
Abstract
Mutation and recombination drive the evolution of most pathogens by generating the genetic variants upon which selection operates. Those variants can, for example, confer resistance to host immune systems and drug therapies or lead to epidemic outbreaks. Given their importance, diverse evolutionary studies have investigated the abundance and consequences of mutation and recombination in pathogen populations. However, some controversies persist regarding the contribution of each evolutionary force to the development of particular phenotypic observations (e.g., drug resistance). In this study, we revise the importance of mutation and recombination in the evolution of pathogens at both intra-host and inter-host levels. We also describe state-of-the-art analytical methodologies to detect and quantify these two evolutionary forces, including biases that are often ignored in evolutionary studies. Finally, we present some of our former studies involving pathogenic taxa where mutation and recombination played crucial roles in the recovery of pathogenic fitness, the generation of interspecific genetic diversity, or the design of centralized vaccines. This review also illustrates several common controversies and pitfalls in the analysis and in the evaluation and interpretation of mutation and recombination outcomes.
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Affiliation(s)
- Miguel Arenas
- Department of Biochemistry, Genetics and Immunology, University of Vigo, Vigo, Spain; Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.
| | - Natalia M Araujo
- Laboratory of Molecular Virology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil.
| | - Catarina Branco
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.
| | - Nadine Castelhano
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.
| | - Eduardo Castro-Nallar
- Universidad Andrés Bello, Center for Bioinformatics and Integrative Biology, Facultad de Ciencias Biológicas, Santiago, Chile.
| | - Marcos Pérez-Losada
- Computational Biology Institute, Milken Institute School of Public Health, George Washington University, Ashburn, VA 20147, Washington, DC, United States; CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, Vairão 4485-661, Portugal.
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Dennehy JJ. Evolutionary ecology of virus emergence. Ann N Y Acad Sci 2016; 1389:124-146. [PMID: 28036113 PMCID: PMC7167663 DOI: 10.1111/nyas.13304] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 10/24/2016] [Accepted: 11/09/2016] [Indexed: 12/22/2022]
Abstract
The cross-species transmission of viruses into new host populations, termed virus emergence, is a significant issue in public health, agriculture, wildlife management, and related fields. Virus emergence requires overlap between host populations, alterations in virus genetics to permit infection of new hosts, and adaptation to novel hosts such that between-host transmission is sustainable, all of which are the purview of the fields of ecology and evolution. A firm understanding of the ecology of viruses and how they evolve is required for understanding how and why viruses emerge. In this paper, I address the evolutionary mechanisms of virus emergence and how they relate to virus ecology. I argue that, while virus acquisition of the ability to infect new hosts is not difficult, limited evolutionary trajectories to sustained virus between-host transmission and the combined effects of mutational meltdown, bottlenecking, demographic stochasticity, density dependence, and genetic erosion in ecological sinks limit most emergence events to dead-end spillover infections. Despite the relative rarity of pandemic emerging viruses, the potential of viruses to search evolutionary space and find means to spread epidemically and the consequences of pandemic viruses that do emerge necessitate sustained attention to virus research, surveillance, prophylaxis, and treatment.
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Affiliation(s)
- John J Dennehy
- Biology Department, Queens College of the City University of New York, Queens, New York and The Graduate Center of the City University of New York, New York, New York
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George B, Alam CM, Kumar RV, Gnanasekaran P, Chakraborty S. Potential linkage between compound microsatellites and recombination in geminiviruses: Evidence from comparative analysis. Virology 2015; 482:41-50. [DOI: 10.1016/j.virol.2015.03.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 02/16/2015] [Accepted: 03/05/2015] [Indexed: 01/10/2023]
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Pérez-Losada M, Arenas M, Galán JC, Palero F, González-Candelas F. Recombination in viruses: mechanisms, methods of study, and evolutionary consequences. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2015; 30:296-307. [PMID: 25541518 PMCID: PMC7106159 DOI: 10.1016/j.meegid.2014.12.022] [Citation(s) in RCA: 198] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Revised: 12/15/2014] [Accepted: 12/17/2014] [Indexed: 02/08/2023]
Abstract
Recombination is a pervasive process generating diversity in most viruses. It joins variants that arise independently within the same molecule, creating new opportunities for viruses to overcome selective pressures and to adapt to new environments and hosts. Consequently, the analysis of viral recombination attracts the interest of clinicians, epidemiologists, molecular biologists and evolutionary biologists. In this review we present an overview of three major areas related to viral recombination: (i) the molecular mechanisms that underlie recombination in model viruses, including DNA-viruses (Herpesvirus) and RNA-viruses (Human Influenza Virus and Human Immunodeficiency Virus), (ii) the analytical procedures to detect recombination in viral sequences and to determine the recombination breakpoints, along with the conceptual and methodological tools currently used and a brief overview of the impact of new sequencing technologies on the detection of recombination, and (iii) the major areas in the evolutionary analysis of viral populations on which recombination has an impact. These include the evaluation of selective pressures acting on viral populations, the application of evolutionary reconstructions in the characterization of centralized genes for vaccine design, and the evaluation of linkage disequilibrium and population structure.
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Affiliation(s)
- Marcos Pérez-Losada
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, Portugal; Computational Biology Institute, George Washington University, Ashburn, VA 20147, USA
| | - Miguel Arenas
- Centre for Molecular Biology "Severo Ochoa", Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Juan Carlos Galán
- Servicio de Microbiología, Hospital Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain; CIBER en Epidemiología y Salud Pública, Spain
| | - Ferran Palero
- CIBER en Epidemiología y Salud Pública, Spain; Unidad Mixta Infección y Salud Pública, FISABIO-Universitat de València, Valencia, Spain
| | - Fernando González-Candelas
- CIBER en Epidemiología y Salud Pública, Spain; Unidad Mixta Infección y Salud Pública, FISABIO-Universitat de València, Valencia, Spain.
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Wu B, Shang X, Schubert J, Habekuß A, Elena SF, Wang X. Global-scale computational analysis of genomic sequences reveals the recombination pattern and coevolution dynamics of cereal-infecting geminiviruses. Sci Rep 2015; 5:8153. [PMID: 25633348 PMCID: PMC4311259 DOI: 10.1038/srep08153] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 12/24/2014] [Indexed: 11/20/2022] Open
Abstract
Genetic diversity and recombination patterns were evaluated for 229 isolates of Wheat dwarf virus (WDV), which are important cereal-infecting geminiviruses. Recombination hot spots were concentrated at the boundary of the genes encoding for the replication protein (Rep), the coat protein (cp) and the movement protein (mp), as well as inside Rep and cp and in the short intergenic regions (SIR). Phylogenomic analyses confirmed that the global population of WDV clustered into two groups according to their specific host: wheat and barley, and the crucial regions for the division of two groups were mp and the large intergenic regions (LIR). The computationally inferred pattern of coevolution between amino acid residues and the predicted 3D structure for the viral proteins provided further differences among the strains or species at the genome and protein level. Pervasive interaction between Rep and Rep A proteins in WDV-wheat-specific group reflected their important and complex function in the replication and transcription of WDV. Furthermore, significant predicted interactions between CP and Rep and CP and Rep A proteins in the WDV-wheat-specific group are thought to be crucial for successful encapsidation and movement of the virus during infection.
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Affiliation(s)
- Beilei Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiaonan Shang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Jörg Schubert
- Institute for Biosafety in Plant Biotechnology, Federal Research Institute for Cultivated Plants, Julius Kuehn Institute, Erwin-Baur-Straβe 27, 06484, Quedlinburg, Germany
| | - Antje Habekuß
- Institute for Resistance Research and Stress Tolerance, Federal Research Institute for Cultivated Plants, Julius Kuehn Institute, Erwin-Baur-Straβe 27, 06484, Quedlinburg, Germany
| | - Santiago F. Elena
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Campus UPV CPI 8E, Ingeniero Fausto Elio s/n, 46022 València, Spain
- The Santa Fe Institute, 1399 Hyde Park Road, Santa Fe NM87501, USA
| | - Xifeng Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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Kehoe MA, Coutts BA, Buirchell BJ, Jones RAC. Split personality of a Potyvirus: to specialize or not to specialize? PLoS One 2014; 9:e105770. [PMID: 25148372 PMCID: PMC4141833 DOI: 10.1371/journal.pone.0105770] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 07/28/2014] [Indexed: 12/04/2022] Open
Abstract
Bean yellow mosaic virus (BYMV), genus Potyvirus, has an extensive natural host range encompassing both dicots and monocots. Its phylogenetic groups were considered to consist of an ancestral generalist group and six specialist groups derived from this generalist group during plant domestication. Recombination was suggested to be playing a role in BYMV's evolution towards host specialization. However, in subsequent phylogenetic analysis of whole genomes, group names based on the original hosts of isolates within each of them were no longer supported. Also, nine groups were found and designated I-IX. Recombination analysis was conducted on the complete coding regions of 33 BYMV genomes and two genomes of the related Clover yellow vein virus (CYVV). This analysis found evidence for 12 firm recombination events within BYMV phylogenetic groups I-VI, but none within groups VII-IX or CYVV. The greatest numbers of recombination events within a sequence (two or three each) occurred in four groups, three which formerly constituted the single ancestral generalist group (I, II and IV), and group VI. The individual sequences in groups III and V had one event each. These findings with whole genomes are consistent with recombination being associated with expanding host ranges, and call into question the proposed role of recombination in the evolution of BYMV, where it was previously suggested to play a role in host specialization. Instead, they (i) indicate that recombination explains the very broad natural host ranges of the three BYMV groups which infect both monocots and dicots (I, II, IV), and (ii) suggest that the three groups with narrow natural host ranges (III, V, VI) which also showed recombination now have the potential to reduce host specificity and broaden their natural host ranges.
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Affiliation(s)
- Monica A. Kehoe
- School of Plant Biology and Institute of Agriculture, Faculty of Science, University of Western Australia, Crawley, WA, Australia
- Crop Protection and Lupin Breeding Branches, Department of Agriculture and Food Western Australia, Bentley Delivery Centre, Perth, WA, Australia
| | - Brenda A. Coutts
- School of Plant Biology and Institute of Agriculture, Faculty of Science, University of Western Australia, Crawley, WA, Australia
- Crop Protection and Lupin Breeding Branches, Department of Agriculture and Food Western Australia, Bentley Delivery Centre, Perth, WA, Australia
| | - Bevan J. Buirchell
- School of Plant Biology and Institute of Agriculture, Faculty of Science, University of Western Australia, Crawley, WA, Australia
- Crop Protection and Lupin Breeding Branches, Department of Agriculture and Food Western Australia, Bentley Delivery Centre, Perth, WA, Australia
| | - Roger A. C. Jones
- School of Plant Biology and Institute of Agriculture, Faculty of Science, University of Western Australia, Crawley, WA, Australia
- Crop Protection and Lupin Breeding Branches, Department of Agriculture and Food Western Australia, Bentley Delivery Centre, Perth, WA, Australia
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Monjane AL, Martin DP, Lakay F, Muhire BM, Pande D, Varsani A, Harkins G, Shepherd DN, Rybicki EP. Extensive recombination-induced disruption of genetic interactions is highly deleterious but can be partially reversed by small numbers of secondary recombination events. J Virol 2014; 88:7843-51. [PMID: 24789787 PMCID: PMC4097777 DOI: 10.1128/jvi.00709-14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 04/22/2014] [Indexed: 01/12/2023] Open
Abstract
Although homologous recombination can potentially provide viruses with vastly more evolutionary options than are available through mutation alone, there are considerable limits on the adaptive potential of this important evolutionary process. Primary among these is the disruption of favorable coevolved genetic interactions that can occur following the transfer of foreign genetic material into a genome. Although the fitness costs of such disruptions can be severe, in some cases they can be rapidly recouped by either compensatory mutations or secondary recombination events. Here, we used a maize streak virus (MSV) experimental model to explore both the extremes of recombination-induced genetic disruption and the capacity of secondary recombination to adaptively reverse almost lethal recombination events. Starting with two naturally occurring parental viruses, we synthesized two of the most extreme conceivable MSV chimeras, each effectively carrying 182 recombination breakpoints and containing thorough reciprocal mixtures of parental polymorphisms. Although both chimeras were severely defective and apparently noninfectious, neither had individual movement-, encapsidation-, or replication-associated genome regions that were on their own "lethally recombinant." Surprisingly, mixed inoculations of the chimeras yielded symptomatic infections with viruses with secondary recombination events. These recombinants had only 2 to 6 breakpoints, had predominantly inherited the least defective of the chimeric parental genome fragments, and were obviously far more fit than their synthetic parents. It is clearly evident, therefore, that even when recombinationally disrupted virus genomes have extremely low fitness and there are no easily accessible routes to full recovery, small numbers of secondary recombination events can still yield tremendous fitness gains. Importance: Recombination between viruses can generate strains with enhanced pathological properties but also runs the risk of producing hybrid genomes with decreased fitness due to the disruption of favorable genetic interactions. Using two synthetic maize streak virus genome chimeras containing alternating genome segments derived from two natural viral strains, we examined both the fitness costs of extreme degrees of recombination (both chimeras had 182 recombination breakpoints) and the capacity of secondary recombination events to recoup these costs. After the severely defective chimeras were introduced together into a suitable host, viruses with between 1 and 3 secondary recombination events arose, which had greatly increased replication and infective capacities. This indicates that even in extreme cases where recombination-induced genetic disruptions are almost lethal, and 91 consecutive secondary recombination events would be required to reconstitute either one of the parental viruses, moderate degrees of fitness recovery can be achieved through relatively small numbers of secondary recombination events.
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Affiliation(s)
- Adérito L Monjane
- Molecular and Cell Biology Department, University of Cape Town, Cape Town, South Africa Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Darren P Martin
- Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Francisco Lakay
- Molecular and Cell Biology Department, University of Cape Town, Cape Town, South Africa
| | - Brejnev M Muhire
- Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Daniel Pande
- Department of Botany and Horticulture, Maseno University, Maseno, Kenya
| | - Arvind Varsani
- School of Biological Sciences and Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand Department of Plant Pathology and Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA Electron Microscope Unit, Division of Medical Biochemistry, Department of Clinical Laboratory Sciences, University of Cape Town, Cape Town, South Africa
| | - Gordon Harkins
- South African National Bioinformatics Institute, MRC Unit for Bioinformatics Capacity Development, University of the Western Cape, Bellville, South Africa
| | - Dionne N Shepherd
- Molecular and Cell Biology Department, University of Cape Town, Cape Town, South Africa
| | - Edward P Rybicki
- Molecular and Cell Biology Department, University of Cape Town, Cape Town, South Africa Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
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Monjane AL, Pande D, Lakay F, Shepherd DN, van der Walt E, Lefeuvre P, Lett JM, Varsani A, Rybicki EP, Martin DP. Adaptive evolution by recombination is not associated with increased mutation rates in Maize streak virus. BMC Evol Biol 2012; 12:252. [PMID: 23268599 PMCID: PMC3556111 DOI: 10.1186/1471-2148-12-252] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Accepted: 12/12/2012] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Single-stranded (ss) DNA viruses in the family Geminiviridae are proving to be very useful in real-time evolution studies. The high mutation rate of geminiviruses and other ssDNA viruses is somewhat mysterious in that their DNA genomes are replicated in host nuclei by high fidelity host polymerases. Although strand specific mutation biases observed in virus species from the geminivirus genus Mastrevirus indicate that the high mutation rates in viruses in this genus may be due to mutational processes that operate specifically on ssDNA, it is currently unknown whether viruses from other genera display similar strand specific mutation biases. Also, geminivirus genomes frequently recombine with one another and an alternative cause of their high mutation rates could be that the recombination process is either directly mutagenic or produces a selective environment in which the survival of mutants is favoured. To investigate whether there is an association between recombination and increased basal mutation rates or increased degrees of selection favoring the survival of mutations, we compared the mutation dynamics of the MSV-MatA and MSV-VW field isolates of Maize streak virus (MSV; Mastrevirus), with both a laboratory constructed MSV recombinant, and MSV recombinants closely resembling MSV-MatA. To determine whether strand specific mutation biases are a general characteristic of geminivirus evolution we compared mutation spectra arising during these MSV experiments with those arising during similar experiments involving the geminivirus Tomato yellow leaf curl virus (Begomovirus genus). RESULTS Although both the genomic distribution of mutations and the occurrence of various convergent mutations at specific genomic sites indicated that either mutation hotspots or selection for adaptive mutations might elevate observed mutation rates in MSV, we found no association between recombination and mutation rates. Importantly, when comparing the mutation spectra of MSV and TYLCV we observed similar strand specific mutation biases arising predominantly from imbalances in the complementary mutations G → T: C → A. CONCLUSIONS While our results suggest that recombination does not strongly influence mutation rates in MSV, they indicate that high geminivirus mutation rates are at least partially attributable to increased susceptibility of all geminivirus genomes to oxidative damage while in a single stranded state.
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Affiliation(s)
- Adérito L Monjane
- Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, Cape Town 7701, South Africa
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Kraberger S, Thomas JE, Geering AD, Dayaram A, Stainton D, Hadfield J, Walters M, Parmenter KS, van Brunschot S, Collings DA, Martin DP, Varsani A. Australian monocot-infecting mastrevirus diversity rivals that in Africa. Virus Res 2012; 169:127-36. [DOI: 10.1016/j.virusres.2012.07.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 07/14/2012] [Accepted: 07/17/2012] [Indexed: 11/26/2022]
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Diemer GS, Stedman KM. A novel virus genome discovered in an extreme environment suggests recombination between unrelated groups of RNA and DNA viruses. Biol Direct 2012; 7:13. [PMID: 22515485 PMCID: PMC3372434 DOI: 10.1186/1745-6150-7-13] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 04/19/2012] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Viruses are known to be the most abundant organisms on earth, yet little is known about their collective origin and evolutionary history. With exceptionally high rates of genetic mutation and mosaicism, it is not currently possible to resolve deep evolutionary histories of the known major virus groups. Metagenomics offers a potential means of establishing a more comprehensive view of viral evolution as vast amounts of new sequence data becomes available for comparative analysis. RESULTS Bioinformatic analysis of viral metagenomic sequences derived from a hot, acidic lake revealed a circular, putatively single-stranded DNA virus encoding a major capsid protein similar to those found only in single-stranded RNA viruses. The presence and circular configuration of the complete virus genome was confirmed by inverse PCR amplification from native DNA extracted from lake sediment. The virus genome appears to be the result of a RNA-DNA recombination event between two ostensibly unrelated virus groups. Environmental sequence databases were examined for homologous genes arranged in similar configurations and three similar putative virus genomes from marine environments were identified. This result indicates the existence of a widespread but previously undetected group of viruses. CONCLUSIONS This unique viral genome carries implications for theories of virus emergence and evolution, as no mechanism for interviral RNA-DNA recombination has yet been identified, and only scant evidence exists that genetic exchange occurs between such distinct virus lineages. REVIEWERS This article was reviewed by EK, MK (nominated by PF) and AM. For the full reviews, please go to the Reviewers' comments section.
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Affiliation(s)
- Geoffrey S Diemer
- Department of Biology, and the Center for Life in Extreme Environments, Portland State University, 1719 SW 10th Avenue, SRTC room 246, Portland, OR 97201, USA
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