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Vassilieff H, Geering ADW, Choisne N, Teycheney PY, Maumus F. Endogenous Caulimovirids: Fossils, Zombies, and Living in Plant Genomes. Biomolecules 2023; 13:1069. [PMID: 37509105 PMCID: PMC10377300 DOI: 10.3390/biom13071069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/26/2023] [Accepted: 06/28/2023] [Indexed: 07/30/2023] Open
Abstract
The Caulimoviridae is a family of double-stranded DNA viruses that infect plants. The genomes of most vascular plants contain endogenous caulimovirids (ECVs), a class of repetitive DNA elements that is abundant in some plant genomes, resulting from the integration of viral DNA in the chromosomes of germline cells during episodes of infection that have sometimes occurred millions of years ago. In this review, we reflect on 25 years of research on ECVs that has shown that members of the Caulimoviridae have occupied an unprecedented range of ecological niches over time and shed light on their diversity and macroevolution. We highlight gaps in knowledge and prospects of future research fueled by increased access to plant genome sequence data and new tools for genome annotation for addressing the extent, impact, and role of ECVs on plant biology and the origin and evolutionary trajectories of the Caulimoviridae.
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Affiliation(s)
| | - Andrew D W Geering
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, QLD 4072, Australia
| | | | - Pierre-Yves Teycheney
- CIRAD, UMR PVBMT, F-97410 Saint-Pierre de La Réunion, France
- UMR PVBMT, Université de la Réunion, F-97410 Saint-Pierre de La Réunion, France
| | - Florian Maumus
- INRAE, URGI, Université Paris-Saclay, 78026 Versailles, France
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2
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Ishwara Bhat A, Selvarajan R, Balasubramanian V. Emerging and Re-Emerging Diseases Caused by Badnaviruses. Pathogens 2023; 12:pathogens12020245. [PMID: 36839517 PMCID: PMC9963457 DOI: 10.3390/pathogens12020245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/27/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
New and emerging plant diseases are caused by different pathogens including viruses that often cause significant crop losses. Badnaviruses are pararetroviruses that contain a single molecule of ds DNA genome of 7 to 9 kb in size and infect a large number of economically important crops such as banana and plantains, black pepper, cacao, citrus, grapevine, pineapple, sugarcane, sweet potato, taro, and yam, causing significant yield losses. Many of the species in the genus have a restricted host range and several of them are known to infect a single crop. Combined infections of different virus species and strains offer conditions that favor the development of new strains via recombination, especially in vegetatively propagated crops. The primary spread of badnaviruses is through vegetative propagating materials while for the secondary spread, they depend on insects such as mealybugs and aphids. Disease emerges as a consequence of the interactions between host and pathogens under favorable environmental conditions. The viral genome of the pararetroviruses is known to be integrated into the chromosome of the host and a few plants with integrants when subjected to different kinds of abiotic stress will give rise to episomal forms of the virus and cause disease. Attempts have been made to develop management strategies for badnaviruses both conventionally and using precision breeding techniques such as genome editing. Until 2016 only 32 badnavirus species infecting different crops were known, but in a span of six years, this number has gone up to 68. The current review highlights the emerging disease problems and management options for badnaviruses infecting economically important crops.
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Affiliation(s)
- Alangar Ishwara Bhat
- Division of Crop Protection, ICAR-Indian Institute of Spices Research, Kozhikode 673012, Kerala, India
| | - Ramasamy Selvarajan
- Division of Crop Protection, ICAR-National Research Centre for Banana, Trichy 620102, Tamil Nadu, India
| | - Velusamy Balasubramanian
- Division of Crop Protection, ICAR-National Research Centre for Banana, Trichy 620102, Tamil Nadu, India
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3
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Diouf MB, Festus R, Silva G, Guyader S, Umber M, Seal S, Teycheney PY. Viruses of Yams (Dioscorea spp.): Current Gaps in Knowledge and Future Research Directions to Improve Disease Management. Viruses 2022; 14:v14091884. [PMID: 36146691 PMCID: PMC9501508 DOI: 10.3390/v14091884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/19/2022] [Accepted: 08/22/2022] [Indexed: 12/24/2022] Open
Abstract
Viruses are a major constraint for yam production worldwide. They hamper the conservation, movement, and exchange of yam germplasm and are a threat to food security in tropical and subtropical areas of Africa and the Pacific where yam is a staple food and a source of income. However, the biology and impact of yam viruses remains largely unknown. This review summarizes current knowledge on yam viruses and emphasizes gaps that exist in the knowledge of the biology of these viruses, their diagnosis, and their impact on production. It provides essential information to inform the implementation of more effective virus control strategies.
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Affiliation(s)
- Mame Boucar Diouf
- INRAE, UR ASTRO, F-97170 Petit-Bourg, France
- CIRAD, UMR AGAP Institut, F-97130 Capesterre-Belle-Eau, France
- UMR AGAP Institut, University Montpellier, CIRAD, INRAE, Institut Agro, F-97130 Capesterre-Belle-Eau, France
| | - Ruth Festus
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent ME4 4TB, UK
| | - Gonçalo Silva
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent ME4 4TB, UK
| | | | - Marie Umber
- INRAE, UR ASTRO, F-97170 Petit-Bourg, France
| | - Susan Seal
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent ME4 4TB, UK
| | - Pierre Yves Teycheney
- CIRAD, UMR PVBMT, F-97410 Saint Pierre, France
- UMR PVBMT, Université de la Réunion, F-97410 Saint-Pierre, France
- Correspondence: ; Tel.: +33-262-492-819
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Silva G, Bömer M, Turaki AA, Nkere CK, Kumar PL, Seal SE. Homing in on Endogenous Badnaviral Elements: Development of Multiplex PCR-DGGE for Detection and Rapid Identification of Badnavirus Sequences in Yam Germplasm. FRONTIERS IN PLANT SCIENCE 2022; 13:846989. [PMID: 35620696 PMCID: PMC9127665 DOI: 10.3389/fpls.2022.846989] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 04/06/2022] [Indexed: 06/15/2023]
Abstract
Viruses of the genus Badnavirus (family Caulimoviridae) are double-stranded DNA-reverse transcribing (dsDNA-RT) plant viruses and have emerged as serious pathogens of tropical and temperate crops globally. Endogenous badnaviral sequences are found integrated in the genomes of several economically important plant species. Infection due to activation of replication-competent integrated copies of the genera Badnavirus, Petuvirus and Cavemovirus has been described. Such endogenous badnaviral elements pose challenges to the development of nucleic acid-based diagnostic methods for episomal virus infections and decisions on health certification for international movement of germplasm and seed. One major food security crop affected is yam (Dioscorea spp.). A diverse range of Dioscorea bacilliform viruses (DBVs), and endogenous DBV (eDBV) sequences have been found to be widespread in yams cultivated in West Africa and other parts of the world. This study outlines the development of multiplex PCR-dependent denaturing gradient gel electrophoresis (PCR-DGGE) to assist in the detection and analysis of eDBVs, through the example of analysing yam germplasm from Nigeria and Ghana. Primers targeting the three most prevalent DBV monophyletic species groups in West Africa were designed to improve DGGE resolution of complex eDBV sequence fingerprints. Multiplex PCR-DGGE with the addition of a tailor-made DGGE sequence marker enables rapid comparison of endogenous badnaviral sequence diversity across germplasm, as illustrated in this study for eDBV diversity in yam.
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Affiliation(s)
- Gonçalo Silva
- Natural Resources Institute, University of Greenwich, Chatham Maritime, United Kingdom
| | - Moritz Bömer
- Natural Resources Institute, University of Greenwich, Chatham Maritime, United Kingdom
| | - Aliyu A. Turaki
- Kebbi State University of Science and Technology Aliero, Birnin Kebbi, Nigeria
| | - Chukwuemeka K. Nkere
- International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria
- Department of Crop Protection and Environmental Biology (CPEB), University of Ibadan, Ibadan, Nigeria
- National Root Crops Research Institute (NRCRI), Umudike, Nigeria
| | - P. Lava Kumar
- International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria
| | - Susan E. Seal
- Natural Resources Institute, University of Greenwich, Chatham Maritime, United Kingdom
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5
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A Review of Viruses Infecting Yam ( Dioscorea spp.). Viruses 2022; 14:v14040662. [PMID: 35458392 PMCID: PMC9033002 DOI: 10.3390/v14040662] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 03/19/2022] [Accepted: 03/21/2022] [Indexed: 02/06/2023] Open
Abstract
Yam is an important food staple for millions of people globally, particularly those in the developing countries of West Africa and the Pacific Islands. To sustain the growing population, yam production must be increased amidst the many biotic and abiotic stresses. Plant viruses are among the most detrimental of plant pathogens and have caused great losses of crop yield and quality, including those of yam. Knowledge and understanding of virus biology and ecology are important for the development of diagnostic tools and disease management strategies to combat the spread of yam-infecting viruses. This review aims to highlight current knowledge on key yam-infecting viruses by examining their characteristics, genetic diversity, disease symptoms, diagnostics, and elimination to provide a synopsis for consideration in developing diagnostic strategy and disease management for yam.
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Bakayoko Y, Kouakou AM, Kouassi AB, Gomez R, Dibi KEB, Essis BS, N’Zué B, Adebola P, N’Guetta AS, Umber M. Detection and diversity of viruses infecting African yam ( Dioscorea rotundata) in a collection and F 1 progenies in Côte d'Ivoire shed light to plant-to-plant viral transmission. PLANT PATHOLOGY 2021; 70:1486-1495. [PMID: 34413548 PMCID: PMC8360134 DOI: 10.1111/ppa.13393] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 04/02/2021] [Accepted: 04/15/2021] [Indexed: 05/03/2023]
Abstract
Yam (Dioscorea spp.) is a major staple food whose production is hampered by viral diseases. However, the prevalence, diversity, transmission, and impact of yam-infecting viruses remain poorly documented. This study reports on the symptomatology, prevalence, and molecular diversity of eight viruses in 38 D. rotundata accessions from a germplasm collection and 206 F1 hybrid progenies maintained in Côte d'Ivoire. Mean severity scores as assessed from leaf symptoms ranged from 2 to 4 in the germplasm collection and from 1 to 3 in F1 hybrids, respectively. Dioscorea mosaic-associated virus (DMaV), potexviruses, and yam mosaic virus (YMV) were detected by PCR-based diagnosis tools in single and mixed infections in both the D. rotundata collection and F1 progenies, whereas badnaviruses were detected only in the germplasm collection. In contrast, cucumber mosaic virus (CMV), yam macluraviruses, yam asymptomatic virus 1 (YaV1), and yam mild mosaic virus (YMMV) could not be detected. No correlation could be established between severity scores and indexing results. Phylogenetic analysis performed on partial viral sequences amplified from infected samples unveiled the presence of two putative novel viral species belonging to genera Badnavirus and Potexvirus and provided evidence for plant-to-plant transmission of YMV, DMaV, and yam potexviruses.
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Affiliation(s)
- Yacouba Bakayoko
- Laboratoire de BiotechnologieAgriculture et Valorisation des Ressources BiologiquesUFR BiosciencesUniversité Félix Houphouët BoignyAbidjanCôte d'Ivoire
- Station de Recherche sur les Cultures Vivrières (SRCVCentre National de Recherche AgronomiqueBouakéCôte d'Ivoire
| | - Amani M. Kouakou
- Station de Recherche sur les Cultures Vivrières (SRCVCentre National de Recherche AgronomiqueBouakéCôte d'Ivoire
| | - Abou B. Kouassi
- Laboratoire de BiotechnologieAgriculture et Valorisation des Ressources BiologiquesUFR BiosciencesUniversité Félix Houphouët BoignyAbidjanCôte d'Ivoire
| | - Rose‐Marie Gomez
- Unité de Recherche Agrosystèmes TropicauxInstitut National de Recherche pour l’Agriculture, l’Alimentation et l’EnvironnementPetit‐BourgGuadeloupeFrance
| | - Konan E. B. Dibi
- Station de Recherche sur les Cultures Vivrières (SRCVCentre National de Recherche AgronomiqueBouakéCôte d'Ivoire
| | - Brice S. Essis
- Station de Recherche sur les Cultures Vivrières (SRCVCentre National de Recherche AgronomiqueBouakéCôte d'Ivoire
| | - Boni N’Zué
- Station de Recherche sur les Cultures Vivrières (SRCVCentre National de Recherche AgronomiqueBouakéCôte d'Ivoire
| | - Patrick Adebola
- International Institut of Tropical AgricultureIITA‐Abuja StationAbujaNigeria
| | - Assanvon S.‐P. N’Guetta
- Laboratoire de BiotechnologieAgriculture et Valorisation des Ressources BiologiquesUFR BiosciencesUniversité Félix Houphouët BoignyAbidjanCôte d'Ivoire
| | - Marie Umber
- Unité de Recherche Agrosystèmes TropicauxInstitut National de Recherche pour l’Agriculture, l’Alimentation et l’EnvironnementPetit‐BourgGuadeloupeFrance
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Umber M, Filloux D, Gélabale S, Gomez RM, Marais A, Gallet S, Gamiette F, Pavis C, Teycheney PY. Molecular Viral Diagnosis and Sanitation of Yam Genetic Resources: Implications for Safe Yam Germplasm Exchange. Viruses 2020; 12:v12101101. [PMID: 33003342 PMCID: PMC7650539 DOI: 10.3390/v12101101] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/24/2020] [Accepted: 09/25/2020] [Indexed: 01/25/2023] Open
Abstract
Yam (Dioscorea spp.) is an important crop in tropical and subtropical regions. Many viruses have been recently identified in yam, hampering genetic conservation and safe international exchanges of yam germplasm. We report on the implementation of reliable and cost-effective PCR-based detection tools targeting eight different yam-infecting viruses. Viral indexing of the in vitro yam collection maintained by the Biological Resources Center for Tropical Plants (BRC-TP) in Guadeloupe (French West Indies) unveiled a high prevalence of potyviruses, badnaviruses, Dioscorea mosaic associated virus (DMaV) and yam asymptomatic virus 1 (YaV1) and a high level of coinfections. Infected yam accessions were subjected to a combination of thermotherapy and meristem culture. Sanitation levels were monitored using PCR-based and high-throughput sequencing-based diagnosis, confirming the efficacy and reliability of PCR-based detection tools. Sanitation rates were highly variable depending on viruses. Sixteen accessions were successfully sanitized, paving the way to safe yam germplasm exchanges and the implementation of clean seed production programs worldwide.
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Affiliation(s)
- Marie Umber
- Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement, Unité de Recherche Agrosystèmes Tropicaux, F-97170 Petit-Bourg, France; (S.G.); (R.-M.G.); (S.G.); (F.G.); (C.P.)
- Correspondence: ; Tel.: +590-590-25-59-29
| | - Denis Filloux
- Centre de Coopération Internationale en Recherche Agronomique Pour le Développement, Unité Mixte de Recherche—Biologie et Génétique des Interactions Plante-Parasite, F-34398 Montpellier, France;
- Biologie et Génétique des Interactions Plante-Parasite, Univ. Montpellier, Centre de Coopération Internationale en Recherche Agronomique Pour le Développement, Institut National de Recherche pour l’Agriculture, Montpellier SupAgro, F-34060 Montpellier, France
| | - Suzia Gélabale
- Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement, Unité de Recherche Agrosystèmes Tropicaux, F-97170 Petit-Bourg, France; (S.G.); (R.-M.G.); (S.G.); (F.G.); (C.P.)
| | - Rose-Marie Gomez
- Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement, Unité de Recherche Agrosystèmes Tropicaux, F-97170 Petit-Bourg, France; (S.G.); (R.-M.G.); (S.G.); (F.G.); (C.P.)
| | - Armelle Marais
- Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement, Université de Bordeaux, Unité Mixte de Recherche Biologie du Fruit et Pathologie, F-33882 Villenave d’Ornon, France;
| | - Séverine Gallet
- Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement, Unité de Recherche Agrosystèmes Tropicaux, F-97170 Petit-Bourg, France; (S.G.); (R.-M.G.); (S.G.); (F.G.); (C.P.)
| | - Franciane Gamiette
- Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement, Unité de Recherche Agrosystèmes Tropicaux, F-97170 Petit-Bourg, France; (S.G.); (R.-M.G.); (S.G.); (F.G.); (C.P.)
| | - Claudie Pavis
- Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement, Unité de Recherche Agrosystèmes Tropicaux, F-97170 Petit-Bourg, France; (S.G.); (R.-M.G.); (S.G.); (F.G.); (C.P.)
| | - Pierre-Yves Teycheney
- Centre de Coopération Internationale en Recherche Agronomique Pour le Développement, Unité Mixte de Recherche Amélioration Génétique et Adaptation des Plantes Méditerranéennes et Tropicales, F-97130 Capesterre Belle-Eau, France;
- Amélioration Génétique et Adaptation des Plantes Méditerranéennes et Tropicales, Univ. Montpellier, Centre de Coopération Internationale en Recherche Agronomique Pour le Développement, Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement, Institut Agro, F-97130 Capesterre Belle-Eau, France
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8
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Zhang F, Yang Z, Hong N, Wang G, Wang A, Wang L. Identification and characterization of water chestnut Soymovirus-1 (WCSV-1), a novel Soymovirus in water chestnuts (Eleocharis dulcis). BMC PLANT BIOLOGY 2019; 19:159. [PMID: 31023231 PMCID: PMC6482551 DOI: 10.1186/s12870-019-1761-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 04/05/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND A disease of unknown etiology in water chestnut plants (Eleocharis dulcis) was reported in China between 2012 and 2014. High throughput sequencing of small RNA (sRNA) combined with bioinformatics, and molecular identification based on PCR detection with virus-specific primers and DNA sequencing is a desirable approach to identify an unknown infectious agent. In this study, we employed this approach to identify viral sequences in water chestnut plants and to explore the molecular interaction of the identified viral pathogen and its natural plant host. RESULTS Based on high throughput sequencing of virus-derived small RNAs (vsRNA), we identified the sequence a new-to-science double-strand DNA virus isolated from water chestnut cv. 'Tuanfeng' samples, a widely grown cultivar in Hubei province, China, and analyzed its genomic organization. The complete genomic sequence is 7535 base-pairs in length, and shares 42-52% nucleotide sequence identity with viruses in the Caulimoviridae family. The virus contains nine predicated open reading frames (ORFs) encoding nine hypothetical proteins, with conserved domains characteristic of caulimoviruses. Phylogenetic analyses at the nucleotide and amino acid levels indicated that the virus belongs to the genus Soymovirus. The virus is tentatively named Water chestnut soymovirus-1 (WCSV-1). Phylogenetic analysis of the putative viral polymerase protein suggested that WCSV-1 is distinct to other well established species in the Soymovirus genus. This conclusion was supported by phylogenetic analyses of the amino acid sequences encoded by ORFs I, IV, VI, or VII. The sRNA bioinformatics showed that the majority of the vsRNAs are 22-nt in length with a preference for U at the 5'-terminal nucleotide. The vsRNAs are unevenly distributed over both strands of the entire WCSV-1 circular genome, and are clustered into small defined regions. In addition, we detected WCSV-1 in asymptomatic and symptomatic water chestnut samples collected from different regions of China by using PCR. RNA-seq assays further confirmed the presence of WCSV-1-derived viral RNA in infected plants. CONCLUSIONS This is the first discovery of a dsDNA virus in the genus Soymovirus infecting water chestnuts. Data presented also add new information towards a better understanding of the co-evolutionary mechanisms between the virus and its natural plant host.
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Affiliation(s)
- Fangpeng Zhang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei People’s Republic of China
- Lab of Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, Hubei People’s Republic of China
| | - Zuokun Yang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei People’s Republic of China
- Lab of Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, Hubei People’s Republic of China
| | - Ni Hong
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei People’s Republic of China
- Lab of Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, Hubei People’s Republic of China
| | - Guoping Wang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei People’s Republic of China
- Lab of Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, Hubei People’s Republic of China
| | - Aiming Wang
- London Research and Development Centre, Agriculture and Agri-Food Canada, London, Ontario N5V 4T3 Canada
| | - Liping Wang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei People’s Republic of China
- Lab of Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, Hubei People’s Republic of China
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9
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Sukal AC, Kidanemariam DB, Dale JL, Harding RM, James AP. Assessment and optimization of rolling circle amplification protocols for the detection and characterization of badnaviruses. Virology 2019; 529:73-80. [PMID: 30665100 DOI: 10.1016/j.virol.2019.01.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 01/13/2019] [Accepted: 01/13/2019] [Indexed: 11/15/2022]
Abstract
The genus Badnavirus is characterized by members that are genetically and serologically heterogeneous which presents challenges for their detection and characterization. The presence of integrated badnavirus-like sequences in some host species further complicates detection using PCR-based protocols. To address these challenges, we have assessed and optimized various RCA protocols including random-primed RCA (RP-RCA), primer-spiked random-primed RCA (primer-spiked RP-RCA), directed RCA (D-RCA) and specific-primed RCA (SP-RCA). Using Dioscorea bacilliform AL virus (DBALV) as an example, we demonstrate that viral DNA amplified using the optimized D-RCA and SP-RCA protocols showed an 85-fold increase in badnavirus NGS reads compared with RP-RCA. The optimized RCA techniques described here were used to detect a range of badnaviruses infecting banana, sugar cane, taro and yam demonstrating the utility of RCA for detection of diverse badnaviruses infecting a variety of host plant species.
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Affiliation(s)
- Amit C Sukal
- Centre for Tropical Crops and Biocommodities (CTCB), Faculty of Science and Engineering (SEF), Queensland University of Technology (QUT), Brisbane 4001, Australia; Centre for Pacific Crops and Trees (CePaCT), Land Resource Division (LRD), Pacific Community (SPC), Suva, Fiji
| | - Dawit B Kidanemariam
- Centre for Tropical Crops and Biocommodities (CTCB), Faculty of Science and Engineering (SEF), Queensland University of Technology (QUT), Brisbane 4001, Australia
| | - James L Dale
- Centre for Tropical Crops and Biocommodities (CTCB), Faculty of Science and Engineering (SEF), Queensland University of Technology (QUT), Brisbane 4001, Australia
| | - Robert M Harding
- Centre for Tropical Crops and Biocommodities (CTCB), Faculty of Science and Engineering (SEF), Queensland University of Technology (QUT), Brisbane 4001, Australia.
| | - Anthony P James
- Centre for Tropical Crops and Biocommodities (CTCB), Faculty of Science and Engineering (SEF), Queensland University of Technology (QUT), Brisbane 4001, Australia
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10
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Bömer M, Rathnayake AI, Visendi P, Sewe SO, Sicat JPA, Silva G, Kumar PL, Seal SE. Tissue culture and next-generation sequencing: A combined approach for detecting yam ( Dioscorea spp.) viruses. PHYSIOLOGICAL AND MOLECULAR PLANT PATHOLOGY 2019; 105:54-66. [PMID: 31007374 PMCID: PMC6472605 DOI: 10.1016/j.pmpp.2018.06.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 05/04/2018] [Accepted: 06/16/2018] [Indexed: 06/09/2023]
Abstract
In vitro culture offers many advantages for yam germplasm conservation, propagation and international distribution. However, low virus titres in the generated tissues pose a challenge for reliable virus detection, which makes it difficult to ensure that planting material is virus-free. In this study, we evaluated next-generation sequencing (NGS) for virus detection following yam propagation using a robust tissue culture methodology. We detected and assembled the genomes of novel isolates of already characterised viral species of the genera Badnavirus and Potyvirus, confirming the utility of NGS in diagnosing yam viruses and contributing towards the safe distribution of germplasm.
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Affiliation(s)
- Moritz Bömer
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
| | - Ajith I. Rathnayake
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
| | - Paul Visendi
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
| | - Steven O. Sewe
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
| | - Juan Paolo A. Sicat
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
| | - Gonçalo Silva
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
| | - P. Lava Kumar
- International Institute of Tropical Agriculture (IITA), Oyo Road, PMB 5320, Ibadan, Nigeria
| | - Susan E. Seal
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
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11
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Sukal AC, Kidanemariam DB, Dale JL, Harding RM, James AP. Characterization of a novel member of the family Caulimoviridae infecting Dioscorea nummularia in the Pacific, which may represent a new genus of dsDNA plant viruses. PLoS One 2018; 13:e0203038. [PMID: 30208072 PMCID: PMC6135502 DOI: 10.1371/journal.pone.0203038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 08/14/2018] [Indexed: 12/17/2022] Open
Abstract
We have characterized the complete genome of a novel circular double-stranded DNA virus, tentatively named Dioscorea nummularia-associated virus (DNUaV), infecting Dioscorea nummularia originating from Samoa. The genome of DNUaV comprised 8139 bp and contained four putative open reading frames (ORFs). ORFs 1 and 2 had no identifiable conserved domains, while ORF 3 had conserved motifs typical of viruses within the family Caulimoviridae including coat protein, movement protein, aspartic protease, reverse transcriptase and ribonuclease H. A transactivator domain, similar to that present in members of several caulimoviridae genera, was also identified in the putative ORF 4. The genome size, organization, and presence of conserved amino acid domains are similar to other viruses in the family Caulimoviridae. However, based on nucleotide sequence similarity and phylogenetic analysis, DNUaV appears to be a distinct novel member of the family and may represent a new genus.
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Affiliation(s)
- Amit C. Sukal
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, Queensland, Australia
- Centre for Pacific Crops and Trees, Pacific Community, Suva, Fiji
| | - Dawit B. Kidanemariam
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, Queensland, Australia
| | - James L. Dale
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Robert M. Harding
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Anthony P. James
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, Queensland, Australia
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12
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Yu H, Wang X, Lu Z, Xu Y, Deng X, Xu Q. Endogenous pararetrovirus sequences are widely present in Citrinae genomes. Virus Res 2018; 262:48-53. [PMID: 29792903 DOI: 10.1016/j.virusres.2018.05.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 05/20/2018] [Accepted: 05/20/2018] [Indexed: 01/04/2023]
Abstract
Endogenous pararetroviruses (EPRVs) are characterized in several plant genomes and their biological effects have been reported. In this study, hundreds of EPRV segments were identified in six Citrinae genomes. A total of 1034 EPRV segments were identified in the genomes of sweet orange, 2036 in pummelo, 598 in clementine mandarin, 752 in Ichang papeda, 2060 in citron and 245 in atalantia. Genomic analysis indicated that EPRV segments tend to cluster as hot spots in the genomes, particularly on chromosome 2 and 5. Large numbers of simple repeats and transposable elements were identified in the 2-kb flanking regions of the EPRV segments. Comparative genomic analysis and PCR experiments showed that there are highly conserved EPRV segments and species-specific EPRV segments between the Citrinae genomes. Phylogenetic analysis suggested that the integration events of EPRVs could initiate in a common progenitor of Citrinae species and repeatedly occur during the Citrinae divergence.
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Affiliation(s)
- Huiwen Yu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Xia Wang
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Zhihao Lu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Yuantao Xu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Xiuxin Deng
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China
| | - Qiang Xu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan 430070, China.
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13
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Li YC, Shen JG, Zhao GH, Yao Q, Li WM. A novel endogenous badnavirus exists in Alhagi sparsifolia. J Zhejiang Univ Sci B 2018; 19:274-284. [PMID: 29616503 DOI: 10.1631/jzus.b1700171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We report the recovery of a 7068-nt viral sequence from the "viral fossils" embedded in the genome of Alhagi sparsifolia, a typical desert plant. Although the full viral genome remains to be completed, the putative genome structure, the deduced amino acids and phylogenetic analysis unambiguously demonstrate that this viral sequence represents a novel species of the genus Badnavirus. The putative virus is tentatively termed Alhagi bacilliform virus (ABV). Southern blotting and inverse polymerase chain reaction (PCR) data indicate that the ABV-related sequence is integrated into the A. sparsifolia genome, and probably does not give rise to functional episomal virus. Molecular evidence that the ABV sequence exists widely in A. sparsifolia is also presented. To our knowledge, this is the first endogenous badnavirus identified from plants in the Gobi desert, and may provide new clues on the evolution, geographical distribution as well as the host range of the badnaviruses.
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Affiliation(s)
- Yong-Chao Li
- Institute of Life Sciences, Jiangsu University, Zhenjiang 212013, China
| | - Jian-Guo Shen
- Inspection & Quarantine Technology Center, Fujian Entry-Exit Inspection and Quarantine Bureau, Fuzhou 350003, China
| | - Guo-Huan Zhao
- Key Laboratory of Agro-Biodiversity and Pest Management of Education Ministry of China, Yunnan Agricultural University, Kunming 650201, China
| | - Qin Yao
- Institute of Life Sciences, Jiangsu University, Zhenjiang 212013, China
| | - Wei-Min Li
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
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14
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Bömer M, Turaki AA, Rathnayake AI, Silva G, Kumar PL, Seal SE. Rolling Circle Amplification to Screen Yam Germplasm for Badnavirus Infections and to Amplify and Characterise Novel Badnavirus Genomes. Bio Protoc 2018; 8:e2672. [PMID: 34179227 DOI: 10.21769/bioprotoc.2672] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 12/11/2017] [Accepted: 12/18/2017] [Indexed: 11/02/2022] Open
Abstract
Since the first discovery of badnaviruses (family Caulimoviridae, genus Badnavirus) in yam (Dioscorea spp.) germplasm in the 1970s (Harrison and Roberts, 1973), several hundred partial badnavirus reverse transcriptase (RT)-ribonuclease H (RNaseH) sequences have been characterised ( Kenyon et al., 2008 ; Bousalem et al., 2009 ), but only a few complete Dioscorea bacilliform virus (DBV) genome sequences have been reported ( Phillips et al., 1999 ; Seal and Muller, 2007; Bömer et al., 2016 and 2017; Sukal et al., 2017 ; Umber et al., 2017 ). We have optimised a workflow involving total nucleic acid extractions and rolling circle amplification (RCA) combined with restriction enzyme analysis for the detection and amplification of DBVs present in yam germplasm. We have employed this approach successfully revealing three novel episomal yam badnaviruses ( Bömer et al., 2016 ). We proposed this to be a complementary method to denaturing gradient gel electrophoresis, which enables a rapid indication of badnavirus diversity as well as the identification of potentially integrated badnavirus sequences in the host genome ( Turaki et al., 2017 ). Here, we describe the step-by-step protocol to screen yam germplasm for badnavirus infections using RCA as an efficient research tool in the amplification and characterization of novel badnavirus genomes.
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Affiliation(s)
- Moritz Bömer
- Natural Resources Institute, University of Greenwich, London, UK
| | - Aliyu A Turaki
- Kebbi State University of Science and Technology Aliero, Birnin Kebbi, Nigeria
| | | | - Gonçalo Silva
- Natural Resources Institute, University of Greenwich, London, UK
| | - P Lava Kumar
- International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria
| | - Susan E Seal
- Natural Resources Institute, University of Greenwich, London, UK
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15
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Bömer M, Rathnayake AI, Visendi P, Silva G, Seal SE. Complete genome sequence of a new member of the genus Badnavirus, Dioscorea bacilliform RT virus 3, reveals the first evidence of recombination in yam badnaviruses. Arch Virol 2017; 163:533-538. [PMID: 29134336 PMCID: PMC5799344 DOI: 10.1007/s00705-017-3605-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 09/27/2017] [Indexed: 11/03/2022]
Abstract
Yams (Dioscorea spp.) host a diverse range of badnaviruses (genus Badnavirus, family Caulimoviridae). The first complete genome sequence of Dioscorea bacilliform RT virus 3 (DBRTV3), which belongs to the monophyletic species group K5, is described. This virus is most closely related to Dioscorea bacilliform SN virus (DBSNV, group K4) based on a comparison of genome sequences. Recombination analysis identified a unique recombination event in DBRTV3, with DBSNV likely to be the major parent and Dioscorea bacilliform AL virus (DBALV) the minor parent, providing the first evidence for recombination in yam badnaviruses. This has important implications for yam breeding programmes globally.
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Affiliation(s)
- Moritz Bömer
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK.
| | - Ajith I Rathnayake
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
| | - Paul Visendi
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
| | - Gonçalo Silva
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
| | - Susan E Seal
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent, ME4 4TB, UK
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16
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PCR-DGGE Analysis: Unravelling Complex Mixtures of Badnavirus Sequences Present in Yam Germplasm. Viruses 2017; 9:v9070181. [PMID: 28696406 PMCID: PMC5537673 DOI: 10.3390/v9070181] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 06/29/2017] [Accepted: 07/04/2017] [Indexed: 12/19/2022] Open
Abstract
Badnaviruses (family Caulimoviridae, genus Badnavirus) have emerged as serious pathogens especially affecting the cultivation of tropical crops. Badnavirus sequences can be integrated in host genomes, complicating the detection of episomal infections and the assessment of viral genetic diversity in samples containing a complex mixture of sequences. Yam (Dioscorea spp.) plants are hosts to a diverse range of badnavirus species, and recent findings have suggested that mixed infections occur frequently in West African yam germplasm. Historically, the determination of the diversity of badnaviruses present in yam breeding lines has been achieved by cloning and sequencing of polymerase chain reaction (PCR) products. In this study, the molecular diversity of partial reverse transcriptase (RT)-ribonuclease H (RNaseH) sequences from yam badnaviruses was analysed using PCR-dependent denaturing gradient gel electrophoresis (PCR-DGGE). This resulted in the identification of complex ‘fingerprints’ composed of multiple sequences of Dioscorea bacilliform viruses (DBVs). Many of these sequences show high nucleotide identities to endogenous DBV (eDBV) sequences deposited in GenBank, and fall into six monophyletic species groups. Our findings highlight PCR-DGGE as a powerful tool in badnavirus diversity studies enabling a rapid indication of sequence diversity as well as potential candidate integrated sequences revealed by their conserved nature across germplasm.
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17
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Deeshma KP, Bhat AI. Occurrence of endogenous Piper yellow mottle virus in black pepper. Virusdisease 2017; 28:213-217. [PMID: 28770249 PMCID: PMC5510636 DOI: 10.1007/s13337-017-0369-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 03/30/2017] [Indexed: 10/19/2022] Open
Abstract
Some badnaviruses are known to occur as endogenous viruses integrated into their host genome. In the present study, Piper yellow mottle virus (PYMoV), a badnavirus infecting black pepper was shown to occur as endogenous virus based on the PCR, reverse transcription (RT)-PCR, ELISA and Southern hybridization tests. Black pepper plants that tested positive in PCR for PYMoV gave negative reaction in RT-PCR indicating that they harbour endogenous PYMoV (ePYMoV) sequences. The RT-PCR (-ve) plants tested negative in ELISA and also in PCR using outword primers to amplify the full circular genome. Further, the presence of ePYMoV sequences in the black pepper genome was confirmed by Southern hybridization analysis using cloned PYMoV genomic fragments as probes. Among different open reading frames (ORFs) of the virus, ORF 3 was more frequently integrated. This is the first report of occurrence of ePYMoV sequences in black pepper genome.
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Affiliation(s)
- K. P. Deeshma
- Division of Crop Protection, ICAR-Indian Institute of Spices Research, Marikunnu, Kozhikode, Kerala 673012 India
| | - A. I. Bhat
- Division of Crop Protection, ICAR-Indian Institute of Spices Research, Marikunnu, Kozhikode, Kerala 673012 India
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18
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The genome sequence of Dioscorea bacilliform TR virus, a member of the genus Badnavirus infecting Dioscorea spp., sheds light on the possible function of endogenous Dioscorea bacilliform viruses. Arch Virol 2016; 162:517-521. [PMID: 27770216 DOI: 10.1007/s00705-016-3113-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 10/05/2016] [Indexed: 01/09/2023]
Abstract
The complete genome sequence of Dioscorea bacilliform TR virus (DBTRV) was determined. The closest relatives of DBTRV are Dioscorea bacilliform AL virus (DBALV) and Dioscorea bacilliform RT virus 1 (DBRTV1). Specific primers were designed and used to determine the prevalence of DBTRV in a yam germplasm collection. It was found that this virus infects Dioscorea alata and D. trifida plants in Guadeloupe and French Guyana. DTRBV was not detected in any of the tested D. cayenensis-rotundata accessions. In silico analysis provided evidence for the presence of DBTRV-like endogenous sequences in the genome of D. cayenensis-rotundata, pointing to a possible role of these sequences in antiviral defense.
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19
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Bömer M, Turaki AA, Silva G, Kumar PL, Seal SE. A Sequence-Independent Strategy for Amplification and Characterisation of Episomal Badnavirus Sequences Reveals Three Previously Uncharacterised Yam Badnaviruses. Viruses 2016; 8:E188. [PMID: 27399761 PMCID: PMC4974523 DOI: 10.3390/v8070188] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 06/24/2016] [Accepted: 06/30/2016] [Indexed: 12/17/2022] Open
Abstract
Yam (Dioscorea spp.) plants are potentially hosts to a diverse range of badnavirus species (genus Badnavirus, family Caulimoviridae), but their detection is complicated by the existence of integrated badnavirus sequences in some yam genomes. To date, only two badnavirus genomes have been characterised, namely, Dioscorea bacilliform AL virus (DBALV) and Dioscorea bacilliform SN virus (DBSNV). A further 10 tentative species in yam have been described based on their partial reverse transcriptase (RT)-ribonuclease H (RNaseH) sequences, generically referred to here as Dioscorea bacilliform viruses (DBVs). Further characterisation of DBV species is necessary to determine which represent episomal viruses and which are only present as integrated badnavirus sequences in some yam genomes. In this study, a sequence-independent multiply-primed rolling circle amplification (RCA) method was evaluated for selective amplification of episomal DBV genomes. This resulted in the identification and characterisation of nine complete genomic sequences (7.4-7.7 kbp) of existing and previously undescribed DBV phylogenetic groups from Dioscorea alata and Dioscorea rotundata accessions. These new yam badnavirus genomes expand our understanding of the diversity and genomic organisation of DBVs, and assist the development of improved diagnostic tools. Our findings also suggest that mixed badnavirus infections occur relatively often in West African yam germplasm.
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Affiliation(s)
- Moritz Bömer
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham, Kent ME4 4TB, UK.
| | - Aliyu A Turaki
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham, Kent ME4 4TB, UK.
| | - Gonçalo Silva
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham, Kent ME4 4TB, UK.
| | - P Lava Kumar
- International Institute of Tropical Agriculture (IITA), Oyo Road, PMB 5320, Ibadan, Nigeria.
| | - Susan E Seal
- Natural Resources Institute, University of Greenwich, Central Avenue, Chatham, Kent ME4 4TB, UK.
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20
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Bhat AI, Hohn T, Selvarajan R. Badnaviruses: The Current Global Scenario. Viruses 2016; 8:E177. [PMID: 27338451 PMCID: PMC4926197 DOI: 10.3390/v8060177] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 05/18/2016] [Accepted: 05/25/2016] [Indexed: 12/16/2022] Open
Abstract
Badnaviruses (Family: Caulimoviridae; Genus: Badnavirus) are non-enveloped bacilliform DNA viruses with a monopartite genome containing about 7.2 to 9.2 kb of dsDNA with three to seven open reading frames. They are transmitted by mealybugs and a few species by aphids in a semi-persistent manner. They are one of the most important plant virus groups and have emerged as serious pathogens affecting the cultivation of several horticultural crops in the tropics, especially banana, black pepper, cocoa, citrus, sugarcane, taro, and yam. Some badnaviruses are also known as endogenous viruses integrated into their host genomes and a few such endogenous viruses can be awakened, e.g., through abiotic stress, giving rise to infective episomal forms. The presence of endogenous badnaviruses poses a new challenge for the fool-proof diagnosis, taxonomy, and management of the diseases. The present review aims to highlight emerging disease problems, virus characteristics, transmission, and diagnosis of badnaviruses.
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Affiliation(s)
| | - Thomas Hohn
- UNIBAS, Botanical Institute, 4056 Basel, Switzerland.
| | - Ramasamy Selvarajan
- ICAR-National Research Centre for Banana, Tiruchirapalli 620102, Tamil Nadu, India.
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