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Tian Y, Fang Y, Zhang K, Zhai Z, Yang Y, He M, Cao X. Applications of Virus-Induced Gene Silencing in Cotton. PLANTS (BASEL, SWITZERLAND) 2024; 13:272. [PMID: 38256825 PMCID: PMC10819639 DOI: 10.3390/plants13020272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/02/2024] [Accepted: 01/13/2024] [Indexed: 01/24/2024]
Abstract
Virus-induced gene silencing (VIGS) is an RNA-mediated reverse genetics technique that has become an effective tool to investigate gene function in plants. Cotton is one of the most important economic crops globally. In the past decade, VIGS has been successfully applied in cotton functional genomic studies, including those examining abiotic and biotic stress responses and vegetative and reproductive development. This article summarizes the traditional vectors used in the cotton VIGS system, the visible markers used for endogenous gene silencing, the applications of VIGS in cotton functional genomics, and the limitations of VIGS and how they can be addressed in cotton.
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Affiliation(s)
- Yue Tian
- College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212003, China; (Y.T.); (Y.F.); (K.Z.); (Z.Z.); (Y.Y.); (M.H.)
- Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agricultural and Rural Areas, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, China
| | - Yao Fang
- College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212003, China; (Y.T.); (Y.F.); (K.Z.); (Z.Z.); (Y.Y.); (M.H.)
- Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agricultural and Rural Areas, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, China
| | - Kaixin Zhang
- College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212003, China; (Y.T.); (Y.F.); (K.Z.); (Z.Z.); (Y.Y.); (M.H.)
- Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agricultural and Rural Areas, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, China
| | - Zeyang Zhai
- College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212003, China; (Y.T.); (Y.F.); (K.Z.); (Z.Z.); (Y.Y.); (M.H.)
- Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agricultural and Rural Areas, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, China
| | - Yujie Yang
- College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212003, China; (Y.T.); (Y.F.); (K.Z.); (Z.Z.); (Y.Y.); (M.H.)
- Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agricultural and Rural Areas, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, China
| | - Meiyu He
- College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212003, China; (Y.T.); (Y.F.); (K.Z.); (Z.Z.); (Y.Y.); (M.H.)
- Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agricultural and Rural Areas, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, China
| | - Xu Cao
- College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212003, China; (Y.T.); (Y.F.); (K.Z.); (Z.Z.); (Y.Y.); (M.H.)
- Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agricultural and Rural Areas, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang 212018, China
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Kreuze JF, Cuellar WJ, Kumar PL, Boddupalli P, Omondi AB. New Technologies Provide Innovative Opportunities to Enhance Understanding of Major Virus Diseases Threatening Global Food Security. PHYTOPATHOLOGY 2023; 113:1622-1629. [PMID: 37311729 DOI: 10.1094/phyto-12-22-0457-v] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Plant viruses pose a continuous and serious threat to crop production worldwide, and globalization and climate change are exacerbating the establishment and rapid spread of new viruses. Simultaneously, developments in genome sequencing technology, nucleic acid amplification methods, and epidemiological modeling are providing plant health specialists with unprecedented opportunities to confront these major threats to the food security and livelihoods of millions of resource-constrained smallholders. In this perspective, we have used recent examples of integrated application of these technologies to enhance understanding of the emergence of plant viral diseases of key food security crops in low- and middle-income countries. We highlight how international funding and collaboration have enabled high-throughput sequencing-based surveillance approaches, targeted field and lab-based diagnostic tools, and modeling approaches that can be effectively used to support surveillance and preparedness against existing and emerging plant viral threats. The importance of national and international collaboration and the future role of CGIAR in further supporting these efforts, including building capabilities to make optimal use of these technologies in low- and middle-income countries, are discussed. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Jan F Kreuze
- One CGIAR Plant Health Initiative
- International Potato Center, Apartado 1558, Lima 15024, Peru
| | - Wilmer J Cuellar
- One CGIAR Plant Health Initiative
- One CGIAR Accelerated Breeding Initiative
- Alliance of Bioversity International and CIAT, Km 17 Recta Cali-Palmira, Cali 763537, Colombia
| | - P Lava Kumar
- One CGIAR Plant Health Initiative
- International Institute of Tropical Agriculture (IITA), PMB 5320, Ibadan, Nigeria
| | - Prasanna Boddupalli
- One CGIAR Plant Health Initiative
- International Maize and Wheat Improvement Center (CIMMYT), ICRAF Campus, UN Avenue, Gigiri, Nairobi, Kenya
| | - Aman B Omondi
- One CGIAR Plant Health Initiative
- Alliance of Bioversity International and CIAT, IPGRI Building, 08BP 0932-Cotonou, Republic of Benin
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Alvarez-Quinto R, Amao M, Muller G, Fuentes S, Grinstead S, Fuentes-Bueno I, Roenhorst A, Westenberg M, Botermans M, Kreuze J, Mollov D. Evidence that an Unnamed Isometric Virus Associated with Potato Rugose Disease in Peru Is a New Species of Genus Torradovirus. PHYTOPATHOLOGY 2023; 113:1716-1728. [PMID: 37486151 DOI: 10.1094/phyto-11-22-0449-v] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
A previously uncharacterized torradovirus species infecting potatoes was detected by high-throughput sequencing from field samples from Peru and in customs intercepts in potato tubers that originated from South America in the United States of America and the Netherlands. This new potato torradovirus showed high nucleotide sequence identity to an unidentified isometric virus (SB26/29), which was associated with a disease named potato rugose stunting in southern Peru characterized over two decades ago. Thus, this virus is tentatively named potato rugose stunting virus (PotRSV). The genome of PotRSV isolates sequenced in this study were composed of two polyadenylated RNA segments. RNA1 ranges from 7,086 to 7,089 nt and RNA2 from 5,228 to 5,230 nt. RNA1 encodes a polyprotein containing the replication block (helicase-protease-polymerase), whereas RNA2 encodes a polyprotein cleaved into a movement protein and the three capsid proteins (CPs). Pairwise comparison among PotRSV isolates revealed amino acid identity values greater than 86% in the protease-polymerase (Pro-Pol) region and greater than 82% for the combined CPs. The closest torradovirus species, squash chlorotic leaf spot virus, shares amino acid identities of ∼58 and ∼41% in the Pro-Pol and the combined CPs, respectively. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.
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Affiliation(s)
- Robert Alvarez-Quinto
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97333, U.S.A
| | - Melody Amao
- Crop and System Sciences Division, International Potato Center, La Molina, Lima 15023, Peru
| | - Giovanna Muller
- Crop and System Sciences Division, International Potato Center, La Molina, Lima 15023, Peru
| | - Segundo Fuentes
- Crop and System Sciences Division, International Potato Center, La Molina, Lima 15023, Peru
| | - Samuel Grinstead
- U.S. Department of Agriculture-Agricultural Research Service, National Germplasm Resources Laboratory, Beltsville, MD 20705, U.S.A
| | - Irazema Fuentes-Bueno
- U.S. Department of Agriculture-Agricultural Research Service, National Germplasm Resources Laboratory, Beltsville, MD 20705, U.S.A
| | - Annelien Roenhorst
- Netherlands Institute for Vectors, Invasive Plants and Plant Health (NIVIP), National Plant Protection Organization, Geertjesweg 15, 6706EA Wageningen, The Netherlands
| | - Marcel Westenberg
- Netherlands Institute for Vectors, Invasive Plants and Plant Health (NIVIP), National Plant Protection Organization, Geertjesweg 15, 6706EA Wageningen, The Netherlands
| | - Marleen Botermans
- Netherlands Institute for Vectors, Invasive Plants and Plant Health (NIVIP), National Plant Protection Organization, Geertjesweg 15, 6706EA Wageningen, The Netherlands
| | - Jan Kreuze
- Crop and System Sciences Division, International Potato Center, La Molina, Lima 15023, Peru
| | - Dimitre Mollov
- U.S. Department of Agriculture-Agricultural Research Service, Horticultural Crops Disease and Pest Management Research Unit, Corvallis, OR 97330, U.S.A
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Alcalá Briseño RI, Batuman O, Brawner J, Cuellar WJ, Delaquis E, Etherton BA, French-Monar RD, Kreuze JF, Navarrete I, Ogero K, Plex Sulá AI, Yilmaz S, Garrett KA. Translating virome analyses to support biosecurity, on-farm management, and crop breeding. FRONTIERS IN PLANT SCIENCE 2023; 14:1056603. [PMID: 36998684 PMCID: PMC10043385 DOI: 10.3389/fpls.2023.1056603] [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: 09/29/2022] [Accepted: 02/14/2023] [Indexed: 06/19/2023]
Abstract
Virome analysis via high-throughput sequencing (HTS) allows rapid and massive virus identification and diagnoses, expanding our focus from individual samples to the ecological distribution of viruses in agroecological landscapes. Decreases in sequencing costs combined with technological advances, such as automation and robotics, allow for efficient processing and analysis of numerous samples in plant disease clinics, tissue culture laboratories, and breeding programs. There are many opportunities for translating virome analysis to support plant health. For example, virome analysis can be employed in the development of biosecurity strategies and policies, including the implementation of virome risk assessments to support regulation and reduce the movement of infected plant material. A challenge is to identify which new viruses discovered through HTS require regulation and which can be allowed to move in germplasm and trade. On-farm management strategies can incorporate information from high-throughput surveillance, monitoring for new and known viruses across scales, to rapidly identify important agricultural viruses and understand their abundance and spread. Virome indexing programs can be used to generate clean germplasm and seed, crucial for the maintenance of seed system production and health, particularly in vegetatively propagated crops such as roots, tubers, and bananas. Virome analysis in breeding programs can provide insight into virus expression levels by generating relative abundance data, aiding in breeding cultivars resistant, or at least tolerant, to viruses. The integration of network analysis and machine learning techniques can facilitate designing and implementing management strategies, using novel forms of information to provide a scalable, replicable, and practical approach to developing management strategies for viromes. In the long run, these management strategies will be designed by generating sequence databases and building on the foundation of pre-existing knowledge about virus taxonomy, distribution, and host range. In conclusion, virome analysis will support the early adoption and implementation of integrated control strategies, impacting global markets, reducing the risk of introducing novel viruses, and limiting virus spread. The effective translation of virome analysis depends on capacity building to make benefits available globally.
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Affiliation(s)
- Ricardo I. Alcalá Briseño
- Plant Pathology Department, University of Florida, Gainesville, FL, United States
- Global Food Systems Institute, University of Florida, Gainesville, FL, United States
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
- Plant Pathology Department, Oregon State University, Corvallis, OR, United States
| | - Ozgur Batuman
- Plant Pathology Department, University of Florida, Gainesville, FL, United States
- Southwest Florida Research and Education Center (SWFREC), Immokalee, FL, United States
| | - Jeremy Brawner
- Plant Pathology Department, University of Florida, Gainesville, FL, United States
| | - Wilmer J. Cuellar
- International Center for Tropical Agriculture (CIAT), Cali, Colombia
| | - Erik Delaquis
- International Center for Tropical Agriculture (CIAT), Vientiane, Laos
| | - Berea A. Etherton
- Plant Pathology Department, University of Florida, Gainesville, FL, United States
- Global Food Systems Institute, University of Florida, Gainesville, FL, United States
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | | | - Jan F. Kreuze
- Crop and System Sciences Division, International Potato Center (CIP), Lima, Peru
| | - Israel Navarrete
- Crop and System Sciences Division, International Potato Center (CIP), Quito, Ecuador
| | - Kwame Ogero
- Crop and System Sciences Division, International Potato Center (CIP), Mwanza, Tanzania
| | - Aaron I. Plex Sulá
- Plant Pathology Department, University of Florida, Gainesville, FL, United States
- Global Food Systems Institute, University of Florida, Gainesville, FL, United States
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
| | - Salih Yilmaz
- Plant Pathology Department, University of Florida, Gainesville, FL, United States
- Southwest Florida Research and Education Center (SWFREC), Immokalee, FL, United States
| | - Karen A. Garrett
- Plant Pathology Department, University of Florida, Gainesville, FL, United States
- Global Food Systems Institute, University of Florida, Gainesville, FL, United States
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States
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Prevalence and molecular characterization of important potato viruses in the Tokat province of Turkey. Mol Biol Rep 2023; 50:2171-2181. [PMID: 36565419 DOI: 10.1007/s11033-022-08134-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 11/17/2022] [Indexed: 12/25/2022]
Abstract
BACKGROUND It is believed that viruses affect potato yield more than any other pathogens worldwide. METHOD AND RESULTS We report here on a survey of the four most common potato viruses in the Tokat Province of northern Turkey. Leaf samples were collected from potato plants showing signs of viral diseases in five districts of the province. Over 400 leaf samples were tested using RT-PCR with virus-specific primers. Among the one or more viruses detected in 218 (52%) leaf samples, Potato virus Y (PVY) was the most common (47.1%), followed by potato virus S (PVS; 16.7%), potato virus X (PVX; 6.0%) and potato leaf roll virus (PLRV; 5.3%). The most common mixed infections were PVY + PVS (6.9%). A phylogenetic analysis of the gene sequences showed all Turkish PVS isolates to be clustered with the PVSO group, two PVY isolates with the PVYN-WI group and one isolate with the PVYNTN group. Turkish PVX isolates are in the Type X group of the two major PVX isolate groups. The Turkish PLRV isolates were separated into two major groups depending on the results of the phylogenetic analysis, with six cases in Group 1 and one in Group 2. CONCLUSIONS PVY, PVX, PVS and PLRV were detected in potato production areas in Tokat. A phylogenetic comparison of the gene sequences revealed all Turkish isolates to be immigrant members of the world populations of these viruses. Our results emphasize the importance of the strict quarantine control of plant materials entering Turkey.
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Role of an RNA pseudoknot involving the polyA tail in replication of Pepino mosaic potexvirus and related plant viruses. Sci Rep 2022; 12:11532. [PMID: 35798958 PMCID: PMC9262919 DOI: 10.1038/s41598-022-15598-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/27/2022] [Indexed: 01/11/2023] Open
Abstract
Pepino mosaic virus (PepMV) is a potexvirus of the family Alphaflexiviridae within the order of Tymovirales that threatens tomato production worldwide. PepMV possesses a positive-strand RNA genome with a 5′-methylguanosine cap and a 3′-polyA tail. Previously, using partially-purified viral RNA polymerase important secondary structures within the 3′-untranslated region (UTR) of PepMV RNA were identified. Here we show that an RNA pseudoknot can be formed in the 3′-UTR that includes part of the polyA tail. Using protoplasts, we demonstrate that the pseudoknot is required for replication of PepMV RNA. Mutational analysis and native gel electrophoresis further show that the pseudoknot is stabilized by UAU base triples, as is the human telomerase RNA pseudoknot. The presence of a pseudoknot in several other members of the Alpha- and Betaflexiviridae is supported by covariance analysis and native gel electrophoresis of other potexvirus, capillovirus and trichovirus RNAs. The ubiquitous presence of the pseudoknot in viruses of the Betaflexiviridae, suggests that the pseudoknot is a typical trait of the Betaflexiviridae that may have been adopted by many potexviruses during evolution.
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Verchot J. Potato virus X: A global potato-infecting virus and type member of the Potexvirus genus. MOLECULAR PLANT PATHOLOGY 2022; 23:315-320. [PMID: 34791766 PMCID: PMC8828454 DOI: 10.1111/mpp.13163] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 05/24/2023]
Abstract
TAXONOMY Potato virus X is the type-member of the plant-infecting Potexvirus genus in the family Alphaflexiviridae. PHYSICAL PROPERTIES Potato virus X (PVX) virions are flexuous filaments 460-480 nm in length. Virions are 13 nm in diameter and have a helical pitch of 3.4 nm. The genome is approximately 6.4 kb with a 5' cap and 3' poly(A) terminus. PVX contains five open reading frames, four of which are essential for cell-to-cell and systemic movement. One protein encodes the viral replicase. Cellular inclusions, known as X-bodies, occur near the nucleus of virus-infected cells. HOSTS The primary host is potato, but it infects a wide range of dicots. Diagnostic hosts include Datura stramonium and Nicotiana tabacum. PVX is transmitted in nature by mechanical contact. USEFUL WEBSITE: https://talk.ictvonline.org/ictv-reports/ictv_online_report/positive-sense-rna-viruses/w/alphaflexiviridae/1330/genus-potexvirus.
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Affiliation(s)
- Jeanmarie Verchot
- Department of Plant Pathology & MicrobiologyTexas A&M UniversityCollege StationTXUSA
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Fuentes S, Gibbs AJ, Adams IP, Hajizadeh M, Kreuze J, Fox A, Blouin AG, Jones RAC. Phylogenetics and Evolution of Potato Virus V: Another Potyvirus that Originated in the Andes. PLANT DISEASE 2022; 106:691-700. [PMID: 34633236 DOI: 10.1094/pdis-09-21-1897-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Potato virus V (PVV) causes a disease of potato (Solanum tubersosum) in South and Central America, Europe, and the Middle East. We report here the complete genomic sequences of 42 new PVV isolates from the potato's Andean domestication center in Peru and of eight historical or recent isolates from Europe. When the principal open reading frames of these genomic sequences together with those of nine previously published genomic sequences were analyzed, only two from Peru and one from Iran were found to be recombinant. The phylogeny of the 56 nonrecombinant open reading frame sequences showed that the PVV population had two major phylogroups, one of which formed three minor phylogroups (A1 to A3) of isolates, all of which are found only in the Andean region of South America (Peru and Colombia), and the other formed two minor phylogroups, a basal one of Andean isolates (A4) that is paraphyletic to a crown cluster containing all the isolates found outside South America (World). This suggests that PVV originated in the Andean region, with only one minor phylogroup spreading elsewhere in the world. In minor phylogroups A1 and A3, there were two subclades on long branches containing isolates from S. phureja evolving more rapidly than the others, and these interfered with dating calculations. Although no temporal signal was directly detected among the dated nonrecombinant sequences, PVV and potato virus Y (PVY) are from the same potyvirus lineage and are ecologically similar, so "subtree dating" was done via a single maximum likelihood phylogeny of PVV and PVY sequences, and PVY's well-supported 157 ce "time to most common recent ancestor" was extrapolated to date that of PVV as 29 bce. Thus the independent historical coincidences supporting the datings of the PVV and PVY phylogenies are the same; PVV arose ≥2,000 years ago in the Andes and was taken to Europe during the Columbian Exchange, where it diversified around 1853 ce, soon after the European potato late blight pandemic. PVV is likely to be more widespread than currently realized and is of biosecurity relevance for world regions that have not yet recorded its presence.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Segundo Fuentes
- Crop and System Sciences Division, International Potato Center, La Molina, Lima 15023, Peru
| | - Adrian J Gibbs
- Emeritus Faculty, Australian National University, Canberra, ACT 2600, Australia
| | - Ian P Adams
- Fera Science Ltd, Sand Hutton, York YO41 1LZ, UK
| | - Mohammad Hajizadeh
- Plant Protection Department, Faculty of Agriculture, University of Kurdistan, Sanandaj 6617715175, Iran
| | - Jan Kreuze
- Crop and System Sciences Division, International Potato Center, La Molina, Lima 15023, Peru
| | - Adrian Fox
- Fera Science Ltd, Sand Hutton, York YO41 1LZ, UK
| | - Arnaud G Blouin
- Plant Pathology Laboratory, TERRA-Gembloux Agro-Bio Tech, University of Liège, Gembloux 5031, Belgium
| | - Roger A C Jones
- University of Western Australia Institute of Agriculture, University of Western Australia, Crawley, WA 6009, Australia
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He M, He CQ, Ding NZ. Evolution of Potato virus X. Mol Phylogenet Evol 2021; 167:107336. [PMID: 34757169 DOI: 10.1016/j.ympev.2021.107336] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 10/01/2021] [Accepted: 10/27/2021] [Indexed: 11/18/2022]
Abstract
Potato virus X (PVX) is the type potexvirus of economic significance. The pathogen is distributed worldwide, threatening solanaceous plants in particular. Based on the coat protein (CP) gene, PVX isolates are classified into two major genotypes (I and II). To gain more insights into the molecular epidemiology and evolution of PVX, recombination analyses were conducted and significant signals were detected. Bayesian coalescent method was then applied to the time-stamped entire CP sequences. According to the estimates, the global subtype I-1 went into expansion in the 20th century and was evolving at a moderate rate. Based on the CP phylogenies, a divergence scenario was proposed for PVX. Surveys of codon usage variation showed that PVX genes had additional bias independent of compositional constraint. In codon preference, PVX was both similar to and different from the three major hosts, potato (Solanum tuberosum), tobacco (Nicotiana tabacum), and tomato (S. lycopersicum). Moreover, the suppression of CpG and UpA dinucleotide frequencies was observed in PVX.
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Affiliation(s)
- Mei He
- College of Life Science, Shandong Normal University, Jinan 250014, China
| | - Cheng-Qiang He
- College of Life Science, Shandong Normal University, Jinan 250014, China.
| | - Nai-Zheng Ding
- College of Life Science, Shandong Normal University, Jinan 250014, China.
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