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Kaponi M, Kyriakopoulou PE, Hadidi A. Viroids of the Mediterranean Basin. Viruses 2024; 16:612. [PMID: 38675953 PMCID: PMC11053799 DOI: 10.3390/v16040612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/08/2024] [Accepted: 04/09/2024] [Indexed: 04/28/2024] Open
Abstract
There has been substantial progress in the Mediterranean countries regarding research on viroids. Twenty-nine viroid species, all belonging to Pospiviroidae and Avsunviroidae genera, have been detected in the Mediterranean Basin. Not only have detection methods, such as reverse transcription-quantitative polymerase chain reaction and next-generation sequencing, been used for viroid detection, along with molecular hybridization techniques allowing for rapid detection, identification, and characterization of known and novel viroids in these countries, but eradication measures have also been taken that allowed for the efficient elimination of certain viroids in a number of Mediterranean countries. The eradication measures were followed as recommended by the European and Mediterranean Plant Protection Organization, which is known by its abbreviation, EPPO. The Mediterranean Region has been a niche for viroids since ancient times due to the warm climate and the socio-cultural conditions that facilitate viroid transmission among different host plant species.
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Affiliation(s)
- Maria Kaponi
- Plant Virology Laboratory, Benaki Phytopathological Institute, Stefanou Delta 8, Kifissia, 14561 Athens, Greece
| | | | - Ahmed Hadidi
- United States Department of Agriculture, Agricultural Research Service, Beltsville, MD 20705, USA;
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2
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Abualrob A, Alabdallah O, Kubaa RA, Naser SM, Alkowni R. Molecular detection of Citrus exocortis viroid (CEVd), Citrus viroid-III (CVd-III), and Citrus viroid-IV (CVd-IV) in Palestine. Sci Rep 2024; 14:423. [PMID: 38172610 PMCID: PMC10764322 DOI: 10.1038/s41598-023-50271-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 12/18/2023] [Indexed: 01/05/2024] Open
Abstract
Citrus hosts various phytopathogens that have impacted productivity, including viroids. Missing data on the status of viroids in citrus in Palestine were not reported. This study was aimed to detect any of Citrus exocortis viroid (CEVd), Citrus viroid-III (CVd-III), and Citrus viroid-IV (CVd-IV) in the Palestinian National Agricultural Research Center (NARC) germplasm collection Field inspections found symptoms such as leaf epinasty; vein discoloration, and bark cracking on various citrus varieties. RT-PCR revealed a significant prevalence of CVd-IV; CEVd and CVd-III (47%, 31%, and 22%; respectively). CVd-III variants with 91.3% nucleic acid sequence homology have been reported. The sequence of each viroid were deposited in GenBank as (OP925746 for CEVd, OP902248 and OP902249 for CVd-III-PS-1 and -PS-2 isolates, and OP902247 for CVd-IV). This was the first to report three of citrus viroids in Palestine, appealing to apply of phytosanitary measures to disseminate healthy propagating materials free from viroids.
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Affiliation(s)
- Aswar Abualrob
- Biology and Biotechnology Department, An-Najah National University, Nablus, Palestine
| | | | - Raied Abou Kubaa
- Department of Plant Pathology, University of California, Davis, CA, 95616, USA
| | - Sabri M Naser
- Biology and Biotechnology Department, An-Najah National University, Nablus, Palestine
| | - Raed Alkowni
- Biology and Biotechnology Department, An-Najah National University, Nablus, Palestine.
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3
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Abstract
Mature viroids consist of a noncoding, covalently closed circular RNA that is able to autonomously infect respective host plants. Thus, they must utilize proteins of the host for most biological functions such as replication, processing, transport, and pathogenesis. Therefore, viroids can be regarded as minimal parasites of the host machinery. They have to present to the host machinery the appropriate signals based on either their sequence or their structure. Here, we summarize such sequence and structural features critical for the biological functions of viroids.
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Affiliation(s)
- Gerhard Steger
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany.
| | - Jean-Pierre Perreault
- Département de biochimie, Faculté de médecine et des sciences de la santé, Pavillon de recherche appliqueé sur le cancer, Université de Sherbrooke, Québec, Canada.
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4
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Elleuch A, Hamdi I, Ellouze O, Ghrab M, Fkahfakh H, Drira N. Pistachio (Pistacia vera L.) is a new natural host of Hop stunt viroid. Virus Genes 2013; 47:330-7. [DOI: 10.1007/s11262-013-0929-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 05/30/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Amine Elleuch
- Laboratoire des Biotechnologies Végétales Appliquées à l'Amélioration des Cultures, Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax, Tunisia,
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5
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Tessitori M, Rizza S, Reina A, Causarano G, Di Serio F. The genetic diversity of Citrus dwarfing viroid populations is mainly dependent on the infected host species. J Gen Virol 2012; 94:687-693. [PMID: 23152366 DOI: 10.1099/vir.0.048025-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
As with viruses, viroids infect their hosts as polymorphic populations of variants. Identifying possible sources of genetic variability is significant in the case of the species Citrus dwarfing viroid (CDVd) which has been proposed as a dwarfing agent for high-density citrus plantings. Here, a natural CDVd isolate (CMC) was used as an inoculum source for long-term (25 years) and short-term (1 year) bioassays in different citrus host species. Characterization of progenies indicated that the genetic stability of CDVd populations was high in certain hosts (trifoliate orange, Troyer citrange, Etrog citron, Navelina sweet orange), which preserve viroid populations similar to the original CMC isolate even after 25 years. By contrast, CDVd variant populations in Interdonato lemon and Volkamer lemon were completely different to those in the inoculated sources, highlighting how influential the host is on the genetic variability of CDVd populations. Implications for risk assessment of CDVd as a dwarfing agent are discussed. The GenBank/EMBL/DDBJ accession numbers for the complete sequences of the Citrus dwarfing viroid variants are JF970266.1 forH2-2, JF970267.1 for H2-7, EU938647.1 for H6-2, EU938651.1 forH6-10, JF970268.1 for H10-7, EU938652.1 for H14-13, EU938653.1for H14-14, JF970269.1 for H14-16, EU938648.1 for H15-9,EU938649.1 for H16-2, JF970265.1 for H16-9, EU938654.1 forH16-13, EU938650.1 for H20-3, JF970270.1 for H20-7, EU938641.1for PR-1, EU938642.1 for PR-3, EU938643.1 for PR-7, EU938644.1for CR-1, EU938639.1 for VR-4, JF12070.1 for VR-15, JF812069.1LS-4, EU938640.1 for LS-10 and JF970264.1 for LS-11.
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Affiliation(s)
- Matilde Tessitori
- Dipartimento di Scienze delle Produzioni Agrarie e Alimentari - Sez. Fitopatologia e Genetica agraria, Università di Catania, 95123 Catania, Italy
| | - Serena Rizza
- Dipartimento di Scienze delle Produzioni Agrarie e Alimentari - Sez. Fitopatologia e Genetica agraria, Università di Catania, 95123 Catania, Italy
| | - Antonella Reina
- Dipartimento di Scienze delle Produzioni Agrarie e Alimentari - Sez. Fitopatologia e Genetica agraria, Università di Catania, 95123 Catania, Italy
| | - Giovanni Causarano
- Dipartimento di Scienze delle Produzioni Agrarie e Alimentari - Sez. Fitopatologia e Genetica agraria, Università di Catania, 95123 Catania, Italy
| | - Francesco Di Serio
- Istituto di Virologia Vegetale, UOS Bari, Consiglio Nazionale delle Ricerche, 70126 Bari, Italy
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Acosta-Leal R, Duffy S, Xiong Z, Hammond RW, Elena SF. Advances in plant virus evolution: translating evolutionary insights into better disease management. PHYTOPATHOLOGY 2011; 101:1136-48. [PMID: 21554186 DOI: 10.1094/phyto-01-11-0017] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Recent studies in plant virus evolution are revealing that genetic structure and behavior of virus and viroid populations can explain important pathogenic properties of these agents, such as host resistance breakdown, disease severity, and host shifting, among others. Genetic variation is essential for the survival of organisms. The exploration of how these subcellular parasites generate and maintain a certain frequency of mutations at the intra- and inter-host levels is revealing novel molecular virus-plant interactions. They emphasize the role of host environment in the dynamic genetic composition of virus populations. Functional genomics has identified host factors that are transcriptionally altered after virus infections. The analyses of these data by means of systems biology approaches are uncovering critical plant genes specifically targeted by viruses during host adaptation. Also, a next-generation resequencing approach of a whole virus genome is opening new avenues to study virus recombination and the relationships between intra-host virus composition and pathogenesis. Altogether, the analyzed data indicate that systematic disruption of some specific parameters of evolving virus populations could lead to more efficient ways of disease prevention, eradication, or tolerable virus-plant coexistence.
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Murcia N, Bernad L, Serra P, Bani Hashemian SM, Duran-Vila N. Molecular and biological characterization of natural variants of Citrus dwarfing viroid. Arch Virol 2009; 154:1329-34. [PMID: 19565323 DOI: 10.1007/s00705-009-0430-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Accepted: 06/10/2009] [Indexed: 11/26/2022]
Abstract
Citrus dwarfing viroid has been proposed as an agent to control tree size in high-density plantations. Thirty-three field isolates have been characterized, and the most frequent sequence/s have been identified. Five distinct variants were selected for biological characterization. Symptom expression analysis demonstrated a good correlation between leaf/stem symptoms and plant growth. The discriminating nucleotide sequence differences included two deletions and an insertion resulting in a reorganization of the base pairing of the terminal left loop, two (G42 --> A and C52 --> U) changes found in one of the variants, and as many as thirteen changes located in the right and left regions flanking the CCR.
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Affiliation(s)
- N Murcia
- Departamento de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias, Centro de Protección Vegetal y Biotecnología, Apartado oficial, 46113 Moncada, Valencia, Spain
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8
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Bernad L, Duran-Vila N, Elena SF. Effect of citrus hosts on the generation, maintenance and evolutionary fate of genetic variability of citrus exocortis viroid. J Gen Virol 2009; 90:2040-2049. [PMID: 19403756 DOI: 10.1099/vir.0.010769-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Citrus exocortis viroid (CEVd) populations are composed of closely related haplotypes whose frequencies in the population result from the equilibrium between mutation, selection and genetic drift. The genetic diversity of CEVd populations infecting different citrus hosts was studied by comparing populations recovered from infected trifoliate orange and sour orange seedling trees after 10 years of evolution, with the ancestral population maintained for the same period in the original host, Etrog citron. Furthermore, populations isolated from these trifoliate orange and sour orange trees were transmitted back to Etrog citron plants and the evolution of their mutant spectra was studied. The results indicate that (i) the amount and composition of the within-plant genetic diversity generated varies between these two hosts and is markedly different from that which is characteristic of the original Etrog citron host and (ii) the genetic diversity found after transmitting back to Etrog citron is indistinguishable from that which is characteristic of the ancestral Etrog citron population, regardless of the citrus plant from which the evolved populations were isolated. The relationship between the CEVd populations from Etrog citron and trifoliate orange, both sensitive hosts, and those from sour orange, which is a tolerant host, is discussed.
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Affiliation(s)
- Lucía Bernad
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias, Moncada, 46113 València, Spain
| | - Núria Duran-Vila
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias, Moncada, 46113 València, Spain
| | - Santiago F Elena
- The Santa Fe Institute, Santa Fe, NM 87501, USA
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, Campus UPV CPI 8E, 46022 València, Spain
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9
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Chao M. RNA recombination in hepatitis delta virus: Implications regarding the abilities of mammalian RNA polymerases. Virus Res 2007; 127:208-15. [PMID: 17296240 DOI: 10.1016/j.virusres.2007.01.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Revised: 10/02/2006] [Accepted: 01/08/2007] [Indexed: 12/18/2022]
Abstract
Hepatitis delta virus (HDV) requires the surface antigens of hepatitis B virus (HBV) for packaging and transmission, but replicates its RNA in an HBV-independent fashion. HDV contains a 1.7-kb circular RNA genome that is folded into an unbranched rod-like structure via intramolecular base-pairing, and possesses ribozyme activity. The HDV genome does not encode an RNA-dependent RNA polymerase (RdRp), but is instead replicated by host RNA polymerase(s) via a rolling-circle mechanism. As such, HDV is similar to the viroid plant pathogens. Recent findings suggest that HDV can also undergo template-switching recombination, a well-documented process that has been found in a large number of RdRp-encoding RNA viruses and is thought to affect viral evolution and pathogenesis. This mini-review examines HDV RNA recombination and how it may improve our understanding of the capacities of host RNA polymerases beyond typical DNA-directed transcription, and speculates on the role of host RNA polymerase-directed RNA template-switching in the origin of HDV.
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Affiliation(s)
- Mei Chao
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, 259, Wen-Hwa 1st Road, Kwei-Shan, Tao-yang 333, Taiwan.
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10
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Owens RA, Baumstark T. Structural differences within the loop E motif imply alternative mechanisms of viroid processing. RNA (NEW YORK, N.Y.) 2007; 13:824-34. [PMID: 17438124 PMCID: PMC1869044 DOI: 10.1261/rna.452307] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Viroids replicate via a rolling circle mechanism, and cleavage/ligation requires extensive rearrangement of the highly base-paired native structure. For Potato spindle tuber viroid (PSTVd), the switch from cleavage to ligation is driven by the change from a multibranched tetraloop structure to a loop E conformation. Here we present evidence that processing of Citrus viroid III (CVd-III), a member of a related group of viroids that also replicate in the nucleus, may proceed via a distinct pathway. Chemical probing of PSTVd and CVd-III miniRNAs with DMS and CMCT revealed that the loop E motifs of these two viroids have quite different tertiary structures. As shown by temperature gradient gel electrophoresis, the presence of two likely Watson-Crick GC pairs results in a significant overall stabilization of the CVd-III loop E-like motif. Unlike PSTVd, the upper strand of the CVd-III loop E-like motif cannot fold into a GNRA tetraloop, and comparison of suboptimal structures indicates that the initial cleavage event could occur on the 5' side of the only GU wobble pair in a helix involving a nearby pair of inverted repeats. According to our model, rearrangement of 3' sequences into a hairpin stem containing an identical arrangement of GC, GU, and CG base pairs and a second cleavage event is followed by formation of loop E, which serves to align the 5' and 3' termini of the CVd-III monomer prior to ligation. Because ligation would occur within loop E itself, stabilization of this motif may be needed to hold the 5' and 3' termini of CVd-III in position for the host ligase.
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Affiliation(s)
- Robert A Owens
- Molecular Plant Pathology Laboratory, Beltsville Agricultural Research Center, Beltsville, Maryland 20705, USA.
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11
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Di Serio F, Daròs JA, Ragozzino A, Flores R. Close structural relationship between two hammerhead viroid-like RNAs associated with cherry chlorotic rusty spot disease. Arch Virol 2006; 151:1539-49. [PMID: 16514498 DOI: 10.1007/s00705-006-0732-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Accepted: 01/16/2006] [Indexed: 10/25/2022]
Abstract
Analysis of the population of cherry small circular RNAs (cscRNAs) from trees affected by cherry chlorotic rusty spot (CCRS) showed two groups of variants with similar sequence but differing in size (394-415 and 372-377 nt for cscRNA1 and cscRNA2, respectively) because of the presence or absence of a 27-nt fragment folding into a hairpin in their predicted quasi-rod-like secondary structures. These structures were preserved by co-variations and compensatory mutations, as well as by additional complex rearrangements. The variability also preserved the central conserved core and the stability of the helices of the plus and minus hammerhead ribozymes, supporting their role in replication of cscRNAs. The smaller variants most likely derive from the larger through recombination events. Possible functional relationships between cscRNAs and certain mycoviral-like double-stranded RNAs, also associated with CCRS, are discussed.
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Affiliation(s)
- F Di Serio
- Instituto di Virologia Vegetale del CNR, Sezione di Bari, Bari, Italy
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12
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Elleuch A, Khouaja FD, Hamdi I, Bsais N, Perreault JP, Marrakchi M, Fakhfakh H. Sequence analysis of three citrus viroids infecting a single Tunisian citrus tree (Citrus, reticulata, Clementine). Genet Mol Biol 2006. [DOI: 10.1590/s1415-47572006000400020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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13
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Wang TC, Chao M. RNA recombination of hepatitis delta virus in natural mixed-genotype infection and transfected cultured cells. J Virol 2005; 79:2221-9. [PMID: 15681424 PMCID: PMC546541 DOI: 10.1128/jvi.79.4.2221-2229.2005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Most RNA viruses encode their own RNA polymerases for genome replication, and increasing numbers of them appear to be capable of undergoing RNA recombination. Here, we provide the first report of intergenotypic recombination in hepatitis delta virus (HDV), the only animal RNA virus that requires host RNA polymerase(s) for viral replication. In vivo, we analyzed RNA species derived from the serum of a patient with mixed genotype I and genotype IIb HDV infection by using multiple restriction fragment length polymorphism (RFLP) assays and sequence analysis of cloned reverse transcription (RT)-PCR products. Six HDV recombinants were isolated from 101 tested clones, and HDV recombination in this patient was further confirmed by RT-PCR with genotype-specific primer pairs. Analysis of the recombination junctions suggested that the HDV genome rearrangement occurred through faithful homologous recombination. We then used an RNA cotransfection cell culture system to investigate HDV RNA recombination in vitro. We found that HDV recombinants could indeed be detected in the transfected cells; some of these possessed recombination junctions identical to those identified in vivo. Furthermore, using a PCR-independent RNase protection assay, we were able to readily identify the recombined HDV RNA species in cultured cells. Taken together, our results demonstrate that HDV RNA recombination occurs in both natural HDV infections and cultured cells, thereby presenting a novel mechanism for HDV evolution.
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Affiliation(s)
- Tzu-Chi Wang
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, 259, Wen-Hwa 1st Rd., Kwei-Shan, Tao-yang 333, Taiwan
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Gandía M, Rubio L, Palacio A, Duran-Vila N. Genetic variation and population structure of an isolate of Citrus exocortis viroid (CEVd) and of the progenies of two infectious sequence variants. Arch Virol 2005; 150:1945-57. [PMID: 15959832 DOI: 10.1007/s00705-005-0570-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2004] [Accepted: 04/28/2005] [Indexed: 10/25/2022]
Abstract
The population structure and diversity within a Citrus exocortis viroid (CEVd) isolate was estimated by single strand conformation polymorphism (SSCP) and sequence analysis. A predominant sequence variant (V1) representing 52.8% of the overall population was identified. V1 and other additional variants presented a composition of the P domain characteristic of severe strains of CEVd. The nucleotide diversity of this CEVd population was lower than expected according to a model of neutral evolution, suggesting a strong negative selection. Citron plants were inoculated with dimeric clones of nine sequence variants and two resulted infectious inducing the severe symptoms characteristic of the original isolate. De novo populations were generated from these infectious variants and like in the original CEVd isolate, both populations presented V1 as the predominant variant but they evolved to a higher nucleotide diversity.
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Affiliation(s)
- M Gandía
- Departamento de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (I.V.I.A), Valencia, Spain
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Vernière C, Perrier X, Dubois C, Dubois A, Botella L, Chabrier C, Bové JM, Vila ND. Citrus Viroids: Symptom Expression and Effect on Vegetative Growth and Yield of Clementine Trees Grafted on Trifoliate Orange. PLANT DISEASE 2004; 88:1189-1197. [PMID: 30795312 DOI: 10.1094/pdis.2004.88.11.1189] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Citrus are natural hosts of five viroid species: Citrus exocortis viroid (CEVd), Citrus bent leaf viroid (CBLVd), Hop stunt viroid (HSVd), Citrus viroid III (CVd-III), and Citrus viroid IV (CVd-IV). CEVd and specific sequence variants of HSVd are the causal agents of the wellknown diseases of citrus, exocortis and cachexia. Other viroids have been found to induce different degrees of stunting. Since commercial citrus trees are commonly infected with mixtures of these viroids, only limited information is available on their effect in species other than Etrog citron. A field assay was conducted to establish the effect of each viroid on Commune clementine trees grafted on Pomeroy trifoliate orange. Infected trees were periodically monitored over a 12-year period (1990 to 2002) for symptom expression, growth, and fruit yield. Only CEVd caused bark scaling on the trifoliate orange rootstock and marked dwarfing, both characteristic of exocortis disease as initially described. In addition, very conspicuous bumps were observed in the wood of the rootstock after removing the bark. Only those HSVd variants, previously characterized as pathogenic in several cachexia-sensitive species, induced pits and gum deposits characteristic of this disease in the clementine scion. Bark cracking symptoms on the trifoliate orange rootstock were also observed. They were associated with CVd-IV, HSVd, or CEVd infection, but in the latter, they were only clearly observed in trees that showed mild scaling. Other abnormalities (deep pits, crests, and gummy pits) were not associated with viroid infection. No specific symptoms resulted from infection with CBLVd and CVd-III. HSVd, CVd-IV, and CBLVd had little or no effect in growth and yield, whereas CEVd and CVd-III caused a significant reduction of growth and yield, which became more pronounced over time with CEVd infection. Yield reduction was associated mainly with loss of production of large fruits. In general, there was a good correlation between reduction in vegetative growth and yield.
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Affiliation(s)
- C Vernière
- Station de Recherches Agronomiques INRA-CIRAD - 20230 San Giuliano, Corsica, France
| | - X Perrier
- Centre International de Recherche pour le Développement, CIRAD-FLHOR, TA50 / PS4, 34398 Montpellier cédex 5, France
| | - C Dubois
- Centre International de Recherche pour le Développement, CIRAD-FLHOR, TA50 / PS4, 34398 Montpellier cédex 5, France
| | - A Dubois
- Station de Recherches Agronomiques INRA-CIRAD - 20230 San Giuliano, Corsica, France
| | - L Botella
- Station de Recherches Agronomiques INRA-CIRAD - 20230 San Giuliano, Corsica, France
| | - C Chabrier
- CIRAD-FLHOR, BP153, 97202 Fort-de France, Martinique
| | - J M Bové
- Institut National de la Recherche Agronomique and Université de Bordeaux 2, IBVM, Laboratoire de Biologie Cellulaire et Moléculaire, BP 81, 33883 Villenave d'Ornon cedex, France
| | - N Duran Vila
- Departamento de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigationes Agrarias, Apartado Oficial, 46113-Moncada, Valencia, Spain
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16
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Affiliation(s)
- T O Diener
- Center for Agricultural Biotechnology, University of Maryland Biotechnology Institute, University of Maryland, College Park, Maryland 20742, USA
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17
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Matousek J, Patzak J, Orctová L, Schubert J, Vrba L, Steger G, Riesner D. The variability of hop latent viroid as induced upon heat treatment. Virology 2001; 287:349-58. [PMID: 11531412 DOI: 10.1006/viro.2001.1044] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We have previously shown that heat treatment of hop plants infected by hop latent viroid (HLVd) reduces viroid levels. Here we investigate whether such heat treatment leads to the accumulation of sequence variability in HLVd. We observed a negligible level of mutated variants in HLVd under standard cultivation conditions. In contrast, the heat treatment of hop led to HLVd degradation and, simultaneously, to a significant increase in sequence variations, as judged from temperature gradient-gel electrophoresis analysis and cDNA library screening by DNA heteroduplex analysis. Thirty-one cDNA clones (9.8%) were identified as deviating forms. Sequencing showed mostly the presence of quadruple and triple mutants, suggesting an accumulation of mutations in HLVd during successive replication cycles. Sixty-nine percent of base changes were localised in the left half and 31% in the right half of the secondary structure proposed for this viroid. No mutations were found in the central part of the upper conserved region. A "hot spot" region was identified in a domain known as a "pathogenicity domain" in the group representative, potato spindle tuber viroid. Most mutations are predicted to destabilise HLVd secondary structure. All mutated cDNAs, however, were infectious and evolved into complex progeny populations containing molecular variants maintained at low levels.
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Affiliation(s)
- J Matousek
- Department of Molecular Genetics, Institute of Plant Molecular Biology Czech Academy of Sciences, Branisovská 31, 37005, Czech Republic
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