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Truniger V, Pechar GS, Aranda MA. Advances in Understanding the Mechanism of Cap-Independent Cucurbit Aphid-Borne Yellows Virus Protein Synthesis. Int J Mol Sci 2023; 24:17598. [PMID: 38139425 PMCID: PMC10744285 DOI: 10.3390/ijms242417598] [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: 10/30/2023] [Revised: 12/07/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
Non-canonical translation mechanisms have been described for many viral RNAs. In the case of several plant viruses, their protein synthesis is controlled by RNA elements in their genomic 3'-ends that are able to enhance cap-independent translation (3'-CITE). The proposed general mechanism of 3'-CITEs includes their binding to eukaryotic translation initiation factors (eIFs) that reach the 5'-end and AUG start codon through 5'-3'-UTR-interactions. It was previously shown that cucurbit aphid-borne yellows virus (CABYV) has a 3'-CITE, which varies in sequence and structure depending on the phylogenetic group to which the isolate belongs, possibly as a result of adaptation to the different geographical regions. In this work, the cap-independent translation mechanisms of two CABYV 3'-CITEs belonging to the Mediterranean (CMTE) and Asian (CXTE) groups, respectively, were studied. In vivo cap-independent translation assays show that these 3'-CITEs require the presence of the CABYV short genomic 5'-UTR with at least 40% adenines in cis and an accessible 5'-end for its activity. Additionally, they suggest that the eIF4E-independent CABYV 3'-CITE activities may not require either eIF4A or the eIF4F complex, but may depend on eIF4G and PABP. By pulling down host proteins using RNA baits containing both 5'- and 3'-CABYV-UTRs, 80 RNA binding proteins were identified. These interacted preferentially with either CMTE, CXTE, or both. One of these proteins, specifically interacting with the RNA containing CMTE, was HSP70.2. Preliminary results suggested that HSP70.2 may be involved in CMTE- but not CXTE-mediated cap-independent translation activity.
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Affiliation(s)
- Verónica Truniger
- Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), 30100 Murcia, Spain; (G.S.P.); (M.A.A.)
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2
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Miras M, Aranda MA, Truniger V. Different RNA Elements Control Viral Protein Synthesis in Polerovirus Isolates Evolved in Separate Geographical Regions. Int J Mol Sci 2022; 23:ijms232012503. [PMID: 36293360 PMCID: PMC9603980 DOI: 10.3390/ijms232012503] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/13/2022] [Accepted: 10/15/2022] [Indexed: 12/05/2022] Open
Abstract
Most plant viruses lack the 5′-cap and 3′-poly(A) structures, which are common in their host mRNAs, and are crucial for translation initiation. Thus, alternative translation initiation mechanisms were identified for viral mRNAs, one of these being controlled by an RNA element in their 3′-ends that is able to enhance mRNA cap-independent translation (3′-CITE). The 3′-CITEs are modular and transferable RNA elements. In the case of poleroviruses, the mechanism of translation initiation of their RNAs in the host cell is still unclear; thus, it was studied for one of its members, cucurbit aphid-borne yellows virus (CABYV). We determined that efficient CABYV RNA translation requires the presence of a 3′-CITE in its 3′-UTR. We showed that this 3′-CITE requires the presence of the 5′-UTR in cis for its eIF4E-independent activity. Efficient virus multiplication depended on 3′-CITE activity. In CABYV isolates belonging to the three phylogenetic groups identified so far, the 3′-CITEs differ, and recombination prediction analyses suggest that these 3′-CITEs have been acquired through recombination with an unknown donor. Since these isolates have evolved in different geographical regions, this may suggest that their respective 3′-CITEs are possibly better adapted to each region. We propose that translation of other polerovirus genomes may also be 3′-CITE-dependent.
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Affiliation(s)
- Manuel Miras
- Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), 30100 Murcia, Spain
- Department of Molecular Physiology, Heinrich Heine University of Düsseldorf, 40225 Düsseldorf, Germany
| | - Miguel A. Aranda
- Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), 30100 Murcia, Spain
| | - Verónica Truniger
- Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), 30100 Murcia, Spain
- Correspondence:
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Navarro JA, Saiz-Bonilla M, Sanchez-Navarro JA, Pallas V. The mitochondrial and chloroplast dual targeting of a multifunctional plant viral protein modulates chloroplast-to-nucleus communication, RNA silencing suppressor activity, encapsidation, pathogenesis and tissue tropism. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 108:197-218. [PMID: 34309112 DOI: 10.1111/tpj.15435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 07/19/2021] [Indexed: 05/22/2023]
Abstract
Plant defense against melon necrotic spot virus (MNSV) is triggered by the viral auxiliary replicase p29 that is targeted to mitochondrial membranes causing morphological alterations, oxidative burst and necrosis. Here we show that MNSV coat protein (CP) was also targeted to mitochondria and mitochondrial-derived replication complexes [viral replication factories or complex (VRC)], in close association with p29, in addition to chloroplasts. CP import resulted in the cleavage of the R/arm domain previously implicated in genome binding during encapsidation and RNA silencing suppression (RSS). We also show that CP organelle import inhibition enhanced RSS activity, CP accumulation and VRC biogenesis but resulted in inhibition of systemic spreading, indicating that MNSV whole-plant infection requires CP organelle import. We hypothesize that to alleviate the p29 impact on host physiology, MNSV could moderate its replication and p29 accumulation by regulating CP RSS activity through organelle targeting and, consequently, eluding early-triggered antiviral response. Cellular and molecular events also suggested that S/P domains, which correspond to processed CP in chloroplast stroma or mitochondrion matrix, could mitigate host response inhibiting p29-induced necrosis. S/P deletion mainly resulted in a precarious balance between defense and counter-defense responses, generating either cytopathic alterations and MNSV cell-to-cell movement restriction or some degree of local movement. In addition, local necrosis and defense responses were dampened when RSS activity but not S/P organelle targeting was affected. Based on a robust biochemical and cellular analysis, we established that the mitochondrial and chloroplast dual targeting of MNSV CP profoundly impacts the viral infection cycle.
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Affiliation(s)
- Jose A Navarro
- Department of Molecular and Evolutionary Plant Virology, Institute for Plant Molecular and Cell Biology, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, Av. Ingeniero Fausto Elio, Valencia, 46022, Spain
| | - Maria Saiz-Bonilla
- Department of Molecular and Evolutionary Plant Virology, Institute for Plant Molecular and Cell Biology, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, Av. Ingeniero Fausto Elio, Valencia, 46022, Spain
| | - Jesus A Sanchez-Navarro
- Department of Molecular and Evolutionary Plant Virology, Institute for Plant Molecular and Cell Biology, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, Av. Ingeniero Fausto Elio, Valencia, 46022, Spain
| | - Vicente Pallas
- Department of Molecular and Evolutionary Plant Virology, Institute for Plant Molecular and Cell Biology, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, Av. Ingeniero Fausto Elio, Valencia, 46022, Spain
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Mackie J, Higgins E, Chambers GA, Tesoriero L, Aldaoud R, Kelly G, Kinoti WM, Rodoni BC, Constable FE. Genome Analysis of Melon Necrotic Spot Virus Incursions and Seed Interceptions in Australia. PLANT DISEASE 2020; 104:1969-1978. [PMID: 32484421 DOI: 10.1094/pdis-04-19-0846-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Melon necrotic spot virus (MNSV) was detected in field-grown Cucumis melo (rockmelon) and Citrullus lanatus (watermelon) plants in the Sunraysia district of New South Wales and Victoria, Australia, in 2012, 2013, and 2016, and in two watermelon seed lots tested at the Australian border in 2016. High-throughput sequencing was used to generate near full-length genomes of six isolates detected during the incursions and seed testing. Phylogenetic analysis of the genomes suggests that there have been at least two incursions of MNSV into Australia and none of the field isolates were the same as the isolates detected in seeds. The analysis indicated that one watermelon field sample (L10), the Victorian rockmelon field sample, and two seed interception samples may have European origins. The results showed that two isolates (L8 and L9) from watermelon were divergent from the type MNSV strain (MNSV-GA, D12536.2) and had 99% nucleotide identity to two MNSV isolates from human stool collected in the United States (KY124135.1, KY124136.1). These isolates also had high nucleotide pairwise identity (96%) to a partial sequence from a Spanish MNSV isolate (KT962848.1). The analysis supported the identification of three previously described MNSV genotype groups: EU-LA, Japan melon, and Japan watermelon. To account for the greater diversity of hosts and geographic regions of the MNSV isolates used in this study, it is suggested that the genotype groups EU-LA, Japan melon, and Japan watermelon be renamed to groups I, II, and III, respectively. The divergent isolates L8 and L9 from this study and the stool isolates from the United States formed a fourth genotype group, group IV. Soil collected from the site of the Victorian rockmelon MNSV outbreak was found to contain viable MNSV and the virus vector, a chytrid fungus, Olpidium bornovanus (Sahtiyanci) Karling, 18 months after the initial MNSV detection. This is a first report of O. bornovanus from soil sampled from an MNSV-contaminated site in Australia.
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Affiliation(s)
- Joanne Mackie
- Agriculture Victoria Research, Department of Jobs, Precincts and Regions, AgriBio, Bundoora, Victoria 3083, Australia
| | - Ellena Higgins
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia
| | - Grant A Chambers
- New South Wales Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, New South Wales 2568, Australia
| | - Len Tesoriero
- New South Wales Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Menangle, New South Wales 2568, Australia
| | - Ramez Aldaoud
- Agriculture Victoria Research, Department of Jobs, Precincts and Regions, AgriBio, Bundoora, Victoria 3083, Australia
| | - Geoff Kelly
- Agriculture Victoria Research, Department of Jobs, Precincts and Regions, AgriBio, Bundoora, Victoria 3083, Australia
| | - Wycliff M Kinoti
- Agriculture Victoria Research, Department of Jobs, Precincts and Regions, AgriBio, Bundoora, Victoria 3083, Australia
| | - Brendan C Rodoni
- Agriculture Victoria Research, Department of Jobs, Precincts and Regions, AgriBio, Bundoora, Victoria 3083, Australia
| | - Fiona E Constable
- Agriculture Victoria Research, Department of Jobs, Precincts and Regions, AgriBio, Bundoora, Victoria 3083, Australia
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5
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Development of monoclonal antibodies against melon necrotic spot virus and their use for virus detection. J Virol Methods 2020; 278:113837. [PMID: 32061591 DOI: 10.1016/j.jviromet.2020.113837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 02/11/2020] [Accepted: 02/11/2020] [Indexed: 11/21/2022]
Abstract
Melon necrotic spot virus (MNSV) is endemic in cucurbit crops worldwide, causing epidemic outbreaks from time to time. MNSV is transmitted in nature by a soil-inhabiting fungus and also through seeds, making its detection in seed certification programs a necessity. Polyclonal antisera and RT-PCR-based detection assays have been developed for MNSV, but up to now no monoclonal antibodies (mAbs) have been described for this virus. In this study, we have produced mAbs in BALB/c mice against the MNSV over-expressed coat protein (CP). Titers of the antibodies produced against the recombinant MNSV CP ranged around 10-3-10-4 and the IgG yields for each mAb from ascitic fluids ranged from 1.51 to 6 mg/mL. Supernatants from ten hybridoma cell lines were evaluated in Western blot analysis and seven of them efficiently recognized the MNSV CP in crude extracts of MNSV-infected leaf material; the 2D4H4 hybridoma cell line was selected for further purification and characterization. The isotype of the 2D4H4 immunoglobulin class was identified as IgG2a and kappa light-chain. Western-blot analyses showed that mAb 2D4H4 provided sensitive and specific detection of MNSV. A TAS-ELISA protocol was developed for mAb 2D4H4. Using this protocol, limits of detection of 1:20,480 and 1:10,240 (g/mL, w/v) were attained for the homologous isolate and a heterologous MNSV isolate, respectively. Moreover, mAb 2D4H4 was used successfully to localize the MNSV CP in infected cells by immunocytochemistry/transmission electron microscopy, illustrating the usefulness of this mAb for advanced cellular studies.
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6
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[Recessive resistance to plant viruses by the deficiency of eukaryotic translation initiation factor genes.]. Uirusu 2020; 70:61-68. [PMID: 33967115 DOI: 10.2222/jsv.70.61] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Plant viruses, obligate parasitic pathogens, utilize a variety of host plant factors in the process of their infection due to the limited number of genes encoded in their own genomes. The genes encoding these host factors are called susceptibility genes because they are responsible for the susceptibility of plants to viruses. Plants lacking or having mutations in a susceptibility gene essential for the infection of a virus acquire resistance to the virus. Such resistance trait is called recessive resistance because of the recessive inherited characteristics. Recessive resistance is reported to account for about half of the plant viral resistance loci mapped in known cultivated crops. Eukaryotic translation initiation factor (eIF) 4E family genes are well-known susceptibility genes. Although there are many reports about eIF4E-mediated recessive resistance to plant viruses, the mechanistic insight of the resistance is still limited. Here we review focusing on studies that have elucidated the mechanism of eIF4E-mediated recessive resistance.
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Rousseau E, Tamisier L, Fabre F, Simon V, Szadkowski M, Bouchez O, Zanchetta C, Girardot G, Mailleret L, Grognard F, Palloix A, Moury B. Impact of genetic drift, selection and accumulation level on virus adaptation to its host plants. MOLECULAR PLANT PATHOLOGY 2018; 19:2575-2589. [PMID: 30074299 PMCID: PMC6638063 DOI: 10.1111/mpp.12730] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The efficiency of plant major resistance genes is limited by the emergence and spread of resistance-breaking mutants. Modulation of the evolutionary forces acting on pathogen populations constitutes a promising way to increase the durability of these genes. We studied the effect of four plant traits affecting these evolutionary forces on the rate of resistance breakdown (RB) by a virus. Two of these traits correspond to virus effective population sizes (Ne ) at either plant inoculation or during infection. The third trait corresponds to differential selection exerted by the plant on the virus population. Finally, the fourth trait corresponds to within-plant virus accumulation (VA). These traits were measured experimentally on Potato virus Y (PVY) inoculated to a set of 84 pepper doubled-haploid lines, all carrying the same pvr23 resistance gene, but having contrasting genetic backgrounds. The lines showed extensive variation for the rate of pvr23 RB by PVY and for the four other traits of interest. A generalized linear model showed that three of these four traits, with the exception of Ne at inoculation, and several pairwise interactions between them had significant effects on RB. RB increased with increasing values of Ne during plant infection or VA. The effect of differential selection was more complex because of a strong interaction with VA. When VA was high, RB increased as the differential selection increased. An opposite relationship between RB and differential selection was observed when VA was low. This study provides a framework to select plants with appropriate virus evolution-related traits to avoid or delay RB.
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Affiliation(s)
- Elsa Rousseau
- Pathologie VégétaleINRA84140MontfavetFrance
- Université Côte d'Azur, Inria, INRA, CNRS, Sorbonne UniversitéBiocore TeamSophia AntipolisFrance
- Université Côte d'Azur, INRA, CNRS, ISAFrance
- Present address:
IBM Almaden Research CenterSan Jose, CA 95120–6099USA
| | - Lucie Tamisier
- Pathologie VégétaleINRA84140MontfavetFrance
- GAFL, INRA84140MontfavetFrance
- Present address:
Université de Liège, Terra‐Gembloux Agro-Bio Tech, PlantPathology Laboratory, Passage des Déportés2, GemblouxBelgium, 5030
| | | | - Vincent Simon
- Pathologie VégétaleINRA84140MontfavetFrance
- UMR BFPINRA33882Villenave d'OrnonFrance
| | | | - Olivier Bouchez
- INRAGeT‐PlaGe, US 1426, Genotoul, 31326 Castanet‐TolosanFrance
| | | | | | - Ludovic Mailleret
- Université Côte d'Azur, Inria, INRA, CNRS, Sorbonne UniversitéBiocore TeamSophia AntipolisFrance
- Université Côte d'Azur, INRA, CNRS, ISAFrance
| | - Frederic Grognard
- Université Côte d'Azur, Inria, INRA, CNRS, Sorbonne UniversitéBiocore TeamSophia AntipolisFrance
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8
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Miras M, Rodríguez-Hernández AM, Romero-López C, Berzal-Herranz A, Colchero J, Aranda MA, Truniger V. A Dual Interaction Between the 5'- and 3'-Ends of the Melon Necrotic Spot Virus (MNSV) RNA Genome Is Required for Efficient Cap-Independent Translation. FRONTIERS IN PLANT SCIENCE 2018; 9:625. [PMID: 29868081 PMCID: PMC5954562 DOI: 10.3389/fpls.2018.00625] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 04/20/2018] [Indexed: 02/05/2023]
Abstract
In eukaryotes, the formation of a 5'-cap and 3'-poly(A) dependent protein-protein bridge is required for translation of its mRNAs. In contrast, several plant virus RNA genomes lack both of these mRNA features, but instead have a 3'-CITE (for cap-independent translation enhancer), a RNA element present in their 3'-untranslated region that recruits translation initiation factors and is able to control its cap-independent translation. For several 3'-CITEs, direct RNA-RNA long-distance interactions based on sequence complementarity between the 5'- and 3'-ends are required for efficient translation, as they bring the translation initiation factors bound to the 3'-CITE to the 5'-end. For the carmovirus melon necrotic spot virus (MNSV), a 3'-CITE has been identified, and the presence of its 5'-end in cis has been shown to be required for its activity. Here, we analyze the secondary structure of the 5'-end of the MNSV RNA genome and identify two highly conserved nucleotide sequence stretches that are complementary to the apical loop of its 3'-CITE. In in vivo cap-independent translation assays with mutant constructs, by disrupting and restoring sequence complementarity, we show that the interaction between the 3'-CITE and at least one complementary sequence in the 5'-end is essential for virus RNA translation, although efficient virus translation and multiplication requires both connections. The complementary sequence stretches are invariant in all MNSV isolates, suggesting that the dual 5'-3' RNA:RNA interactions are required for optimal MNSV cap-independent translation and multiplication.
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Affiliation(s)
- Manuel Miras
- Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), Murcia, Spain
| | - Ana M Rodríguez-Hernández
- Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), Murcia, Spain.,Centro de Investigación en Química Aplicada, Consejo Nacional de Ciencia y Tecnología (CONACYT), Saltillo, Mexico
| | - Cristina Romero-López
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), Granada, Spain
| | - Alfredo Berzal-Herranz
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas (IPBLN-CSIC), Granada, Spain
| | - Jaime Colchero
- Departamento de Física, Edificio CIOyN, Universidad de Murcia, Campus de Espinardo, Murcia, Spain
| | - Miguel A Aranda
- Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), Murcia, Spain
| | - Verónica Truniger
- Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), Murcia, Spain
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Eoche-Bosy D, Gautier M, Esquibet M, Legeai F, Bretaudeau A, Bouchez O, Fournet S, Grenier E, Montarry J. Genome scans on experimentally evolved populations reveal candidate regions for adaptation to plant resistance in the potato cyst nematode Globodera pallida. Mol Ecol 2017; 26:4700-4711. [PMID: 28734070 DOI: 10.1111/mec.14240] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 07/13/2017] [Accepted: 07/17/2017] [Indexed: 12/30/2022]
Abstract
Improving resistance durability involves to be able to predict the adaptation speed of pathogen populations. Identifying the genetic bases of pathogen adaptation to plant resistances is a useful step to better understand and anticipate this phenomenon. Globodera pallida is a major pest of potato crop for which a resistance QTL, GpaVvrn , has been identified in Solanum vernei. However, its durability is threatened as G. pallida populations are able to adapt to the resistance in few generations. The aim of this study was to investigate the genomic regions involved in the resistance breakdown by coupling experimental evolution and high-density genome scan. We performed a whole-genome resequencing of pools of individuals (Pool-Seq) belonging to G. pallida lineages derived from two independent populations having experimentally evolved on susceptible and resistant potato cultivars. About 1.6 million SNPs were used to perform the genome scan using a recent model testing for adaptive differentiation and association to population-specific covariables. We identified 275 outliers and 31 of them, which also showed a significant reduction in diversity in adapted lineages, were investigated for their genic environment. Some candidate genomic regions contained genes putatively encoding effectors and were enriched in SPRYSECs, known in cyst nematodes to be involved in pathogenicity and in (a)virulence. Validated candidate SNPs will provide a useful molecular tool to follow frequencies of virulence alleles in natural G. pallida populations and define efficient strategies of use of potato resistances maximizing their durability.
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Affiliation(s)
- D Eoche-Bosy
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
| | - M Gautier
- CBGP, INRA, IRD, CIRAD, Montpellier SupAgro, Montferrier-sur-Lez, France.,IBC, Montpellier, France
| | - M Esquibet
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
| | - F Legeai
- IGEPP, BIPAA, INRA, Agrocampus Ouest, Université de Rennes 1, Rennes, France.,IRISA, GenScale, INRIA, Rennes, France
| | - A Bretaudeau
- IGEPP, BIPAA, INRA, Agrocampus Ouest, Université de Rennes 1, Rennes, France.,IRISA, GenOuest COre Facility, INRIA, Rennes, France
| | - O Bouchez
- GeT-PlaGe, Genotoul, INRA, Castanet-Tolosan, France.,GenPhySE, Université de Toulouse, INRA, INPT, ENVT, Castanet-Tolosan, France
| | - S Fournet
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
| | - E Grenier
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
| | - J Montarry
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
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10
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Miras M, Truniger V, Querol‐Audi J, Aranda MA. Analysis of the interacting partners eIF4F and 3'-CITE required for Melon necrotic spot virus cap-independent translation. MOLECULAR PLANT PATHOLOGY 2017; 18:635-648. [PMID: 27145354 PMCID: PMC6638222 DOI: 10.1111/mpp.12422] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/26/2016] [Accepted: 04/28/2016] [Indexed: 05/17/2023]
Abstract
We have shown previously that the translation of Melon necrotic spot virus (MNSV, family Tombusviridae, genus Carmovirus) RNAs is controlled by a 3'-cap-independent translation enhancer (CITE), which is genetically and functionally dependent on the eukaryotic translation initiation factor (eIF) 4E. Here, we describe structural and functional analyses of the MNSV-Mα5 3'-CITE and its translation initiation factor partner. We first mapped the minimal 3'-CITE (Ma5TE) to a 45-nucleotide sequence, which consists of a stem-loop structure with two internal loops, similar to other I-shaped 3'-CITEs. UV crosslinking, followed by gel retardation assays, indicated that Ma5TE interacts in vitro with the complex formed by eIF4E + eIF4G980-1159 (eIF4Fp20 ), but not with each subunit alone or with eIF4E + eIF4G1003-1092 , suggesting binding either through interaction with eIF4E following a conformational change induced by its binding to eIF4G980-1159 , or through a double interaction with eIF4E and eIF4G980-1159 . Critical residues for this interaction reside in an internal bulge of Ma5TE, so that their mutation abolished binding to eIF4E + eIF4G1003-1092 and cap-independent translation. We also developed an in vivo system to test the effect of mutations in eIF4E in Ma5TE-driven cap-independent translation, showing that conserved amino acids in a positively charged RNA-binding motif around amino acid position 228, implicated in eIF4E-eIF4G binding or belonging to the cap-recognition pocket, are essential for cap-independent translation controlled by Ma5TE, and thus for the multiplication of MNSV.
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Affiliation(s)
- Manuel Miras
- Centro de Edafología y Biología Aplicada del Segura (CEBAS) ‐ CSICApdo. correos 164, 30100 EspinardoMurciaSpain
| | - Verónica Truniger
- Centro de Edafología y Biología Aplicada del Segura (CEBAS) ‐ CSICApdo. correos 164, 30100 EspinardoMurciaSpain
| | - Jordi Querol‐Audi
- Molecular Biology Institute of Barcelona (IBMB‐CSIC)Parc Científic de Barcelona, Baldiri i Reixac 10Barcelona08028Spain
| | - Miguel A. Aranda
- Centro de Edafología y Biología Aplicada del Segura (CEBAS) ‐ CSICApdo. correos 164, 30100 EspinardoMurciaSpain
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11
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Deficiency of the eIF4E isoform nCBP limits the cell-to-cell movement of a plant virus encoding triple-gene-block proteins in Arabidopsis thaliana. Sci Rep 2017; 7:39678. [PMID: 28059075 PMCID: PMC5216350 DOI: 10.1038/srep39678] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 11/25/2016] [Indexed: 01/19/2023] Open
Abstract
One of the important antiviral genetic strategies used in crop breeding is recessive resistance. Two eukaryotic translation initiation factor 4E family genes, eIF4E and eIFiso4E, are the most common recessive resistance genes whose absence inhibits infection by plant viruses in Potyviridae, Carmovirus, and Cucumovirus. Here, we show that another eIF4E family gene, nCBP, acts as a novel recessive resistance gene in Arabidopsis thaliana toward plant viruses in Alpha- and Betaflexiviridae. We found that infection by Plantago asiatica mosaic virus (PlAMV), a potexvirus, was delayed in ncbp mutants of A. thaliana. Virus replication efficiency did not differ between an ncbp mutant and a wild type plant in single cells, but viral cell-to-cell movement was significantly delayed in the ncbp mutant. Furthermore, the accumulation of triple-gene-block protein 2 (TGB2) and TGB3, the movement proteins of potexviruses, decreased in the ncbp mutant. Inoculation experiments with several viruses showed that the accumulation of viruses encoding TGBs in their genomes decreased in the ncbp mutant. These results indicate that nCBP is a novel member of the eIF4E family recessive resistance genes whose loss impairs viral cell-to-cell movement by inhibiting the efficient accumulation of TGB2 and TGB3.
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Gómez-Aix C, Pascual L, Cañizares J, Sánchez-Pina MA, Aranda MA. Transcriptomic profiling of Melon necrotic spot virus-infected melon plants revealed virus strain and plant cultivar-specific alterations. BMC Genomics 2016; 17:429. [PMID: 27267368 PMCID: PMC4897865 DOI: 10.1186/s12864-016-2772-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 05/25/2016] [Indexed: 12/03/2022] Open
Abstract
Background Viruses are among the most destructive and difficult to control plant pathogens. Melon (Cucumis melo L.) has become the model species for the agriculturally important Cucurbitaceae family. Approaches that take advantage of recently developed genomic tools in melon have been extremely useful for understanding viral pathogenesis and can contribute to the identification of target genes for breeding new resistant cultivars. In this work, we have used a recently described melon microarray for transcriptome profiling of two melon cultivars infected with two strains of Melon necrotic spot virus (MNSV) that only differ on their 3′-untranslated regions. Results Melon plant tissues from the cultivars Tendral or Planters Jumbo were locally infected with either MNSV-Mα5 or MNSV-Mα5/3’264 and analysed in a time-course experiment. Principal component and hierarchical clustering analyses identified treatment (healthy vs. infected) and sampling date (3 vs. 5 dpi) as the primary and secondary variables, respectively. Out of 7566 and 7074 genes deregulated by MNSV-Mα5 and MNSV-Mα5/3’264, 1851 and 1356, respectively, were strain-specific. Likewise, MNSV-Mα5/3’264 specifically deregulated 2925 and 1618 genes in Tendral and Planters Jumbo, respectively. The GO categories that were significantly affected were clearly different for the different virus/host combinations. Grouping genes according to their patterns of expression allowed for the identification of two groups that were specifically deregulated by MNSV-Mα5/3’264 with respect to MNSV-Mα5 in Tendral, and one group that was antagonistically regulated in Planters Jumbo vs. Tendral after MNSV-Mα5/3’264 infection. Genes in these three groups belonged to diverse functional classes, and no obvious regulatory commonalities were identified. When data on MNSV-Mα5/Tendral infections were compared to equivalent data on cucumber mosaic virus or watermelon mosaic virus infections, cytokinin-O-glucosyltransferase2 was identified as the only gene that was deregulated by all three viruses, with infection dynamics correlating with the amplitude of transcriptome remodeling. Conclusions Strain-specific changes, as well as cultivar-specific changes, were identified by profiling the transcriptomes of plants from two melon cultivars infected with two MNSV strains. No obvious regulatory features shared among deregulated genes have been identified, pointing toward regulation through differential functional pathways. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2772-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Cristina Gómez-Aix
- Departamento de Biología del Estrés y Patología Vegetal, Centro de Edafología y Biología Aplicada del Segura (CEBAS) - CSIC, apdo. correos 164, 30100, Espinardo, Murcia, Spain
| | - Laura Pascual
- Centre for Research in Agricultural Genomics CRAG, CSIC-IRTA-UAB-UB, Campus 10 UAB Bellaterra, 08193, Barcelona, Spain
| | - Joaquín Cañizares
- Instituto de Conservación y Mejora de la Agrodiversidad Valenciana (COMAV) - UPV, Camino de Vera s/n, 46022, Valencia, Spain
| | - María Amelia Sánchez-Pina
- Departamento de Biología del Estrés y Patología Vegetal, Centro de Edafología y Biología Aplicada del Segura (CEBAS) - CSIC, apdo. correos 164, 30100, Espinardo, Murcia, Spain
| | - Miguel A Aranda
- Departamento de Biología del Estrés y Patología Vegetal, Centro de Edafología y Biología Aplicada del Segura (CEBAS) - CSIC, apdo. correos 164, 30100, Espinardo, Murcia, Spain.
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Guiu-Aragonés C, Díaz-Pendón JA, Martín-Hernández AM. Four sequence positions of the movement protein of Cucumber mosaic virus determine the virulence against cmv1-mediated resistance in melon. MOLECULAR PLANT PATHOLOGY 2015; 16:675-84. [PMID: 25470079 PMCID: PMC6638431 DOI: 10.1111/mpp.12225] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The resistance to a set of strains of Cucumber mosaic virus (CMV) in the melon accession PI 161375, cultivar 'Songwhan Charmi', is dependent on one recessive gene, cmv1, which confers total resistance, whereas a second set of strains is able to overcome it. We tested 11 strains of CMV subgroups I and II in the melon line SC12-1-99, which carries the gene cmv1, and showed that this gene confers resistance to strains of subgroup II only and that restriction is not related to either viral replication or cell-to-cell movement. This is the first time that a resistant trait has been correlated with CMV subgroups. Using infectious clones of the CMV strains LS (subgroup II) and FNY (subgroup I), we generated rearrangements and viral chimaeras between both strains and established that the determinant of virulence against the gene cmv1 resides in the first 209 amino acids of the movement protein, as this region from FNY is sufficient to confer virulence to the LS clone in the line SC12-1-99. A comparison of the sequences of the strains of both subgroups in this region shows that there are five main positions shared by all strains of subgroup II, which are different from those of subgroup I. Site-directed mutagenesis of the CMV-LS clone to substitute these residues for those of CMV-FNY revealed that a combination of four of these changes [the group 64-68 (SNNLL to HGRIA), and the point mutations R81C, G171T and A195I] was required for a complete gain of function of the LS MP in the resistant melon plant.
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Affiliation(s)
- Cèlia Guiu-Aragonés
- IRTA, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Edifici CRAG, Campus UAB, Cerdanyola del Vallès, 08193, Barcelona, Spain
| | - Juan Antonio Díaz-Pendón
- Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora', Universidad de Málaga-Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Estación Experimental 'La Mayora', 29750, Algarrobo-Costa, Málaga, Spain
| | - Ana Montserrat Martín-Hernández
- IRTA, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Edifici CRAG, Campus UAB, Cerdanyola del Vallès, 08193, Barcelona, Spain
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Plant Translation Factors and Virus Resistance. Viruses 2015; 7:3392-419. [PMID: 26114476 PMCID: PMC4517107 DOI: 10.3390/v7072778] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 06/18/2015] [Accepted: 06/19/2015] [Indexed: 02/06/2023] Open
Abstract
Plant viruses recruit cellular translation factors not only to translate their viral RNAs but also to regulate their replication and potentiate their local and systemic movement. Because of the virus dependence on cellular translation factors, it is perhaps not surprising that many natural plant recessive resistance genes have been mapped to mutations of translation initiation factors eIF4E and eIF4G or their isoforms, eIFiso4E and eIFiso4G. The partial functional redundancy of these isoforms allows specific mutation or knock-down of one isoform to provide virus resistance without hindering the general health of the plant. New possible targets for antiviral strategies have also been identified following the characterization of other plant translation factors (eIF4A-like helicases, eIF3, eEF1A and eEF1B) that specifically interact with viral RNAs and proteins and regulate various aspects of the infection cycle. Emerging evidence that translation repression operates as an alternative antiviral RNA silencing mechanism is also discussed. Understanding the mechanisms that control the development of natural viral resistance and the emergence of virulent isolates in response to these plant defense responses will provide the basis for the selection of new sources of resistance and for the intelligent design of engineered resistance that is broad-spectrum and durable.
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Gómez-Aix C, García-García M, Aranda MA, Sánchez-Pina MA. Melon necrotic spot virus Replication Occurs in Association with Altered Mitochondria. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:387-97. [PMID: 25372121 DOI: 10.1094/mpmi-09-14-0274-r] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Melon necrotic spot virus (MNSV) (genus Carmovirus, family Tombusviridae) is a single-stranded, positive-sense RNA virus that has become an experimental model for the analysis of cell-to-cell virus movement and translation of uncapped viral RNAs, whereas little is known about its replication. Analysis of the cytopathology after MNSV infection showed the specific presence of modified organelles that resemble mitochondria. Immunolocalization of the glycine decarboxylase complex (GDC) P protein in these organelles confirmed their mitochondrial origin. In situ hybridization and immunolocalization experiments showed the specific localization of positive-sense viral RNA, capsid protein (CP), and double-stranded (ds)RNA in these organelles meaning that replication of the virus takes place in association with them. The three-dimensional reconstructions of the altered mitochondria showed the presence of large, interconnected, internal dilations which appeared to be linked to the outside cytoplasmic environment through pores and/or complex structures, and with lipid bodies. Transient expression of MNSV p29 revealed that its specific target is mitochondria. Our data document the extensive reorganization of host mitochondria induced by MNSV, which provides a protected environment to viral replication, and show that the MNSV p29 protein is the primary determinant of this effect in the host.
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Affiliation(s)
- Cristina Gómez-Aix
- 1 Centro de Edafología y Biología Aplicada del Segura (CEBAS)-CSIC, P.O. Box 164, 30100 Espinardo, Murcia, Spain
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Herranz MC, Navarro JA, Sommen E, Pallas V. Comparative analysis among the small RNA populations of source, sink and conductive tissues in two different plant-virus pathosystems. BMC Genomics 2015; 16:117. [PMID: 25765188 PMCID: PMC4345012 DOI: 10.1186/s12864-015-1327-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 02/06/2015] [Indexed: 01/29/2024] Open
Abstract
Background In plants, RNA silencing plays a fundamental role as defence mechanism against viruses. During last years deep-sequencing technology has allowed to analyze the sRNA profile of a large variety of virus-infected tissues. Nevertheless, the majority of these studies have been restricted to a unique tissue and no comparative analysis between phloem and source/sink tissues has been conducted. In the present work, we compared the sRNA populations of source, sink and conductive (phloem) tissues in two different plant virus pathosystems. We chose two cucurbit species infected with two viruses very different in genome organization and replication strategy; Melon necrotic spot virus (MNSV) and Prunus necrotic ringspot virus (PNRSV). Results Our findings showed, in both systems, an increase of the 21-nt total sRNAs together with a decrease of those with a size of 24-nt in all the infected tissues, except for the phloem where the ratio of 21/24-nt sRNA species remained constant. Comparing the vsRNAs, both PNRSV- and MNSV-infected plants share the same vsRNA size distribution in all the analyzed tissues. Similar accumulation levels of sense and antisense vsRNAs were observed in both systems except for roots that showed a prevalence of (+) vsRNAs in both pathosystems. Additionally, the presence of overrepresented discrete sites along the viral genome, hot spots, were identified and validated by stem-loop RT-PCR. Despite that in PNRSV-infected plants the presence of vsRNAs was scarce both viruses modulated the host sRNA profile. Conclusions We compare for the first time the sRNA profile of four different tissues, including source, sink and conductive (phloem) tissues, in two plant-virus pathosystems. Our results indicate that antiviral silencing machinery in melon and cucumber acts mainly through DCL4. Upon infection, the total sRNA pattern in phloem remains unchanged in contrast to the rest of the analyzed tissues indicating a certain tissue-tropism to this polulation. Independently of the accumulation level of the vsRNAs both viruses were able to modulate the host sRNA pattern. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1327-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mari Carmen Herranz
- Instituto de Biología Celular y Molecular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Campus UPV, CPI 8E, Avda. Ingeniero Fausto Elio s/n, Valencia, 46022, Spain.
| | - Jose Antonio Navarro
- Instituto de Biología Celular y Molecular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Campus UPV, CPI 8E, Avda. Ingeniero Fausto Elio s/n, Valencia, 46022, Spain.
| | - Evelien Sommen
- Instituto de Biología Celular y Molecular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Campus UPV, CPI 8E, Avda. Ingeniero Fausto Elio s/n, Valencia, 46022, Spain.
| | - Vicente Pallas
- Instituto de Biología Celular y Molecular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Campus UPV, CPI 8E, Avda. Ingeniero Fausto Elio s/n, Valencia, 46022, Spain.
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Miras M, Sempere RN, Kraft JJ, Miller WA, Aranda MA, Truniger V. Interfamilial recombination between viruses led to acquisition of a novel translation-enhancing RNA element that allows resistance breaking. THE NEW PHYTOLOGIST 2014; 202:233-246. [PMID: 24372390 PMCID: PMC4337425 DOI: 10.1111/nph.12650] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 11/19/2013] [Indexed: 05/04/2023]
Abstract
Many plant viruses depend on functional RNA elements, called 3'-UTR cap-independent translation enhancers (3'-CITEs), for translation of their RNAs. In this manuscript we provide direct proof for the existing hypothesis that 3'-CITEs are modular and transferable by recombination in nature, and that this is associated with an advantage for the created virus. By characterizing a newly identified Melon necrotic spot virus (MNSV; Tombusviridae) isolate, which is able to overcome eukaryotic translation initiation factor 4E (eIF4E)-mediated resistance, we found that it contains a 55 nucleotide insertion in its 3'-UTR. We provide strong evidence that this insertion was acquired by interfamilial recombination with the 3'-UTR of an Asiatic Cucurbit aphid-borne yellows virus (CABYV; Luteoviridae). By constructing chimeric viruses, we showed that this recombined sequence is responsible for resistance breaking. Analysis of the translational efficiency of reporter constructs showed that this sequence functions as a novel 3'-CITE in both resistant and susceptible plants, being essential for translation control in resistant plants. In conclusion, we showed that a recombination event between two clearly identified viruses from different families led to the transfer of exactly the sequence corresponding to a functional RNA element, giving rise to a new isolate with the capacity to infect an otherwise nonsusceptible host.
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Affiliation(s)
- Manuel Miras
- Centro de Edafología y Biología Aplicada del Segura (CEBAS), Consejo Superior de Investigaciones Científicas (CSIC), Apdo. Correos 164, 30100 Espinardo, Murcia, Spain
| | - Raquel N. Sempere
- Centro de Edafología y Biología Aplicada del Segura (CEBAS), Consejo Superior de Investigaciones Científicas (CSIC), Apdo. Correos 164, 30100 Espinardo, Murcia, Spain
| | - Jelena J. Kraft
- Department of Plant Pathology and Microbiology, Iowa State University, 351 Bessey Hall, Ames, IA 50011, USA
| | - W. Allen Miller
- Department of Plant Pathology and Microbiology, Iowa State University, 351 Bessey Hall, Ames, IA 50011, USA
| | - Miguel A. Aranda
- Centro de Edafología y Biología Aplicada del Segura (CEBAS), Consejo Superior de Investigaciones Científicas (CSIC), Apdo. Correos 164, 30100 Espinardo, Murcia, Spain
| | - Veronica Truniger
- Centro de Edafología y Biología Aplicada del Segura (CEBAS), Consejo Superior de Investigaciones Científicas (CSIC), Apdo. Correos 164, 30100 Espinardo, Murcia, Spain
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Abstract
More than 70 well-characterized virus species transmitted by a diversity of vectors may infect cucurbit crops worldwide. Twenty of those cause severe epidemics in major production areas, occasionally leading to complete crop failures. Cucurbit viruses' control is based on three major axes: (i) planting healthy seeds or seedlings in a clean environment, (ii) interfering with vectors activity, and (iii) using resistant cultivars. Seed disinfection and seed or seedling quality controls guarantee growers on the sanitary status of their planting material. Removal of virus or vector sources in the crop environment can significantly delay the onset of viral epidemics. Insecticide or oil application may reduce virus spread in some situations. Diverse cultural practices interfere with or prevent vector reaching the crop. Resistance can be obtained by grafting for soil-borne viruses, by cross-protection, or generally by conventional breeding or genetic engineering. The diversity of the actions that may be taken to limit virus spread in cucurbit crops and their limits will be discussed. The ultimate goal is to provide farmers with technical packages that combine these methods within an integrated disease management program and are adapted to different countries and cropping systems.
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Affiliation(s)
- Hervé Lecoq
- INRA, UR407, Station de Pathologie Végétale, Montfavet Cedex, France.
| | - Nikolaos Katis
- Faculty of Agriculture, Forestry and Natural Environment, School of Agriculture, Plant Pathology Lab, Aristotle University of Thessaloniki, Thessaloniki, Greece
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19
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Abstract
In the absence of a 5' cap, plant positive-strand RNA viruses have evolved a number of different elements in their 3' untranslated region (UTR) to attract initiation factors and/or ribosomes to their templates. These 3' cap-independent translational enhancers (3' CITEs) take different forms, such as I-shaped, Y-shaped, T-shaped, or pseudoknotted structures, or radiate multiple helices from a central hub. Common features of most 3' CITEs include the ability to bind a component of the translation initiation factor eIF4F complex and to engage in an RNA-RNA kissing-loop interaction with a hairpin loop located at the 5' end of the RNA. The two T-shaped structures can bind to ribosomes and ribosomal subunits, with one structure also able to engage in a simultaneous long-distance RNA-RNA interaction. Several of these 3' CITEs are interchangeable and there is evidence that natural recombination allows exchange of modular CITE units, which may overcome genetic resistance or extend the virus's host range.
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Affiliation(s)
- Anne E Simon
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742;
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Reinbold C, Lacombe S, Ziegler-Graff V, Scheidecker D, Wiss L, Beuve M, Caranta C, Brault V. Closely related poleroviruses depend on distinct translation initiation factors to infect Arabidopsis thaliana. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:257-265. [PMID: 23013438 DOI: 10.1094/mpmi-07-12-0174-r] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In addition to being essential for translation of eukaryotic mRNA, translation initiation factors are also key components of plant-virus interactions. In order to address the involvement of these factors in the infectious cycle of poleroviruses (aphid-transmitted, phloem-limited viruses), the accumulation of three poleroviruses was followed in Arabidopsis thaliana mutant lines impaired in the synthesis of translation initiation factors in the eIF4E and eIF4G families. We found that efficient accumulation of Turnip yellows virus (TuYV) in A. thaliana relies on the presence of eIF (iso)4G1, whereas Beet mild yellowing virus (BMYV) and Beet western yellows virus-USA (BWYV-USA) rely, instead, on eIF4E1. A role for these factors in the infectious processes of TuYV and BMYV was confirmed by direct interaction in yeast between these specific factors and the 5' viral genome-linked protein of the related virus. Although the underlying molecular mechanism is still unknown, this study reveals a totally unforeseen situation in which closely related viruses belonging to the same genus use different translation initiation factors for efficient infection of A. thaliana.
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Affiliation(s)
- C Reinbold
- INRA, UMR 1131 SVQV, 28 rue de Herrlisheim, F-68021 Colmar, France
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Rodríguez-Hernández AM, Gosalvez B, Sempere RN, Burgos L, Aranda MA, Truniger V. Melon RNA interference (RNAi) lines silenced for Cm-eIF4E show broad virus resistance. MOLECULAR PLANT PATHOLOGY 2012; 13:755-63. [PMID: 22309030 PMCID: PMC6638723 DOI: 10.1111/j.1364-3703.2012.00785.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Efficient and sustainable control of plant viruses may be achieved using genetically resistant crop varieties, although resistance genes are not always available for each pathogen; in this regard, the identification of new genes that are able to confer broad-spectrum and durable resistance is highly desirable. Recently, the cloning and characterization of recessive resistance genes from different plant species has pointed towards eukaryotic translation initiation factors (eIF) of the 4E family as factors required for the multiplication of many different viruses. Thus, we hypothesized that eIF4E may control the susceptibility of melon (Cucumis melo L.) to a broad range of viruses. To test this hypothesis, Cm-eIF4E knockdown melon plants were generated by the transformation of explants with a construct that was designed to induce the silencing of this gene, and the plants from T2 generations were genetically and phenotypically characterized. In transformed plants, Cm-eIF4E was specifically silenced, as identified by the decreased accumulation of Cm-eIF4E mRNA and the appearance of small interfering RNAs derived from the transgene, whereas the Cm-eIF(iso)4E mRNA levels remained unaffected. We challenged these transgenic melon plants with eight agronomically important melon-infecting viruses, and identified that they were resistant to Cucumber vein yellowing virus (CVYV), Melon necrotic spot virus (MNSV), Moroccan watermelon mosaic virus (MWMV) and Zucchini yellow mosaic virus (ZYMV), indicating that Cm-eIF4E controls melon susceptibility to these four viruses. Therefore, Cm-eIF4E is an efficient target for the identification of new resistance alleles able to confer broad-spectrum virus resistance in melon.
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Affiliation(s)
- Ana M Rodríguez-Hernández
- Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas, Apdo, Correos 164, 30100 Espinardo (Murcia), Spain
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Abstract
Cucurbit crops may be affected by at least 28 different viruses in the Mediterranean basin. Some of these viruses are widely distributed and cause severe yield losses while others are restricted to limited areas or specific crops, and have only a negligible economic impact. A striking feature of cucurbit viruses in the Mediterranean basin is their always increasing diversity. Indeed, new viruses are regularly isolated and over the past 35 years one "new" cucurbit virus has been reported on average every 2 years. Among these "new" viruses some were already reported in other parts of the world, but others such as Zucchini yellow mosaic virus (ZYMV), one of the most severe cucurbit viruses and Cucurbit aphid-borne yellows virus (CABYV), one of the most prevalent cucurbit viruses, were first described in the Mediterranean area. Why this region may be a potential "hot-spot" for cucurbit virus diversity is not fully known. This could be related to the diversity of cropping practices, of cultivar types but also to the important commercial exchanges that always prevailed in this part of the world. This chapter describes the major cucurbit viruses occurring in the Mediterranean basin, discusses factors involved in their emergence and presents options for developing sustainable control strategies.
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Affiliation(s)
- Hervé Lecoq
- INRA, UR407 Pathologie Végétale, Domaine Saint Maurice, Montfavet, France
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Pallas V, García JA. How do plant viruses induce disease? Interactions and interference with host components. J Gen Virol 2011; 92:2691-2705. [PMID: 21900418 DOI: 10.1099/vir.0.034603-0] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Plant viruses are biotrophic pathogens that need living tissue for their multiplication and thus, in the infection-defence equilibrium, they do not normally cause plant death. In some instances virus infection may have no apparent pathological effect or may even provide a selective advantage to the host, but in many cases it causes the symptomatic phenotypes of disease. These pathological phenotypes are the result of interference and/or competition for a substantial amount of host resources, which can disrupt host physiology to cause disease. This interference/competition affects a number of genes, which seems to be greater the more severe the symptoms that they cause. Induced or repressed genes belong to a broad range of cellular processes, such as hormonal regulation, cell cycle control and endogenous transport of macromolecules, among others. In addition, recent evidence indicates the existence of interplay between plant development and antiviral defence processes, and that interference among the common points of their signalling pathways can trigger pathological manifestations. This review provides an update on the latest advances in understanding how viruses affect substantial cellular processes, and how plant antiviral defences contribute to pathological phenotypes.
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Affiliation(s)
- Vicente Pallas
- Instituto de Biología Molecular y Celular de las Plantas, CSIC-Universidad Politécnica de Valencia, Avenida de los Naranjos s/n, 46022 Valencia, Spain
| | - Juan Antonio García
- Centro Nacional de Biotecnología-CSIC, Campus de la Universidad Autónoma de Madrid, 28049 Madrid, Spain
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Gonzalez-Ibeas D, Blanca J, Donaire L, Saladié M, Mascarell-Creus A, Cano-Delgado A, Garcia-Mas J, Llave C, Aranda MA. Analysis of the melon (Cucumis melo) small RNAome by high-throughput pyrosequencing. BMC Genomics 2011; 12:393. [PMID: 21812964 PMCID: PMC3163571 DOI: 10.1186/1471-2164-12-393] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 08/03/2011] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Melon (Cucumis melo L.) is a commercially important fruit crop that is cultivated worldwide. The melon research community has recently benefited from the determination of a complete draft genome sequence and the development of associated genomic tools, which have allowed us to focus on small RNAs (sRNAs). These are short, non-coding RNAs 21-24 nucleotides in length with diverse physiological roles. In plants, they regulate gene expression and heterochromatin assembly, and control protection against virus infection. Much remains to be learned about the role of sRNAs in melon. RESULTS We constructed 10 sRNA libraries from two stages of developing ovaries, fruits and photosynthetic cotyledons infected with viruses, and carried out high-throughput pyrosequencing. We catalogued and analysed the melon sRNAs, resulting in the identification of 26 known miRNA families (many conserved with other species), the prediction of 84 melon-specific miRNA candidates, the identification of trans-acting siRNAs, and the identification of chloroplast, mitochondrion and transposon-derived sRNAs. In silico analysis revealed more than 400 potential targets for the conserved and novel miRNAs. CONCLUSION We have discovered and analysed a large number of conserved and melon-specific sRNAs, including miRNAs and their potential target genes. This provides insight into the composition and function of the melon small RNAome, and paves the way towards an understanding of sRNA-mediated processes that regulate melon fruit development and melon-virus interactions.
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Affiliation(s)
- Daniel Gonzalez-Ibeas
- Departamento de Biología del Estrés y Patología Vegetal, Centro de Edafología y Biología Aplicada del Segura (CEBAS) - CSIC, Apdo. correos 164, 30100 Espinardo (Murcia), Spain
| | - José Blanca
- Departamento de Biotecnología, Instituto de Conservación y Mejora de la Agrodiversidad Valenciana (COMAV) - UPV, Camino de Vera s/n, 46022 Valencia, Spain
| | - Livia Donaire
- Departamento de Biología Medioambiental, Centro de Investigaciones Biológicas (CIB) - CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Montserrat Saladié
- IRTA, Center for Research in Agricultural Genomics CSIC-IRTA-UAB, Campus UAB, Edifici CRAG, Bellaterra (Cerdanyola del Vallès), 08193 (Barcelona), Spain
| | - Albert Mascarell-Creus
- Molecular Genetics Department, Center for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB, Campus UAB, Edifici CRAG, Bellaterra (Cerdanyola del Vallès), 08193 (Barcelona), Spain
| | - Ana Cano-Delgado
- Molecular Genetics Department, Center for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB, Campus UAB, Edifici CRAG, Bellaterra (Cerdanyola del Vallès), 08193 (Barcelona), Spain
| | - Jordi Garcia-Mas
- IRTA, Center for Research in Agricultural Genomics CSIC-IRTA-UAB, Campus UAB, Edifici CRAG, Bellaterra (Cerdanyola del Vallès), 08193 (Barcelona), Spain
| | - Cesar Llave
- Departamento de Biología Medioambiental, Centro de Investigaciones Biológicas (CIB) - CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Miguel A Aranda
- Departamento de Biología del Estrés y Patología Vegetal, Centro de Edafología y Biología Aplicada del Segura (CEBAS) - CSIC, Apdo. correos 164, 30100 Espinardo (Murcia), Spain
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Moury B, Caromel B, Johansen E, Simon V, Chauvin L, Jacquot E, Kerlan C, Lefebvre V. The helper component proteinase cistron of Potato virus Y induces hypersensitivity and resistance in Potato genotypes carrying dominant resistance genes on chromosome IV. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:787-797. [PMID: 21405985 DOI: 10.1094/mpmi-10-10-0246] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The Nc(tbr) and Ny(tbr) genes in Solanum tuberosum determine hypersensitive reactions, characterized by necrotic reactions and restriction of the virus systemic movement, toward isolates belonging to clade C and clade O of Potato virus Y (PVY), respectively. We describe a new resistance from S. sparsipilum which possesses the same phenotype and specificity as Nc(tbr) and is controlled by a dominant gene designated Nc(spl). Nc(spl) maps on potato chromosome IV close or allelic to Ny(tbr). The helper component proteinase (HC-Pro) cistron of PVY was shown to control necrotic reactions and resistance elicitation in plants carrying Nc(spl), Nc(tbr), and Ny(tbr). However, inductions of necrosis and of resistance to the systemic virus movement in plants carrying Nc(spl) reside in different regions of the HC-Pro cistron. Also, genomic determinants outside the HC-Pro cistron are involved in the systemic movement of PVY after induction of necroses on inoculated leaves of plants carrying Ny(tbr). These results suggest that the Ny(tbr) resistance may have been involved in the recent emergence of PVY isolates with a recombination breakpoint near the junction of HC-Pro and P3 cistrons in potato crops. Therefore, this emergence could constitute one of the rare examples of resistance breakdown by a virus which was caused by recombination instead of by successive accumulation of nucleotide substitutions.
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Affiliation(s)
- Benoît Moury
- INRA, UR407 Pathologie Vegetale, Montfavet, France.
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26
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Nieto C, Rodríguez-Moreno L, Rodríguez-Hernández AM, Aranda MA, Truniger V. Nicotiana benthamiana resistance to non-adapted Melon necrotic spot virus results from an incompatible interaction between virus RNA and translation initiation factor 4E. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 66:492-501. [PMID: 21255163 DOI: 10.1111/j.1365-313x.2011.04507.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Nicotiana benthamiana has been described as non-host for Melon necrotic spot virus (MNSV). We investigated the basis of this resistance using the unique opportunity provided by strain MNSV-264, a recombinant virus that is able to overcome the resistance. Analysis of chimeric MNSV mutants showed that virulence in N. benthamiana is conferred by a 49 nucleotide section of the MNSV-264 3'-UTR, which acts in this host as a cap-independent translational enhancer (3'-CITE). Although the 3'-CITE of non-adapted MNSV-Mα5 is active in susceptible melon, it does not promote efficient translation in N. benthamiana, thus preventing expression of proteins required for virus replication. However, MNSV-Mα5 gains the ability to multiply in N. benthamiana cells if eIF4E from a susceptible melon variety (Cm-eIF4E-S) is supplied in trans. These data show that N. benthamiana resistance to MNSV-Mα5 results from incompatibility between the MNSV-Mα5 3'-CITE and N. benthamiana eIF4E in initiating efficient translation of the viral genome. Therefore, non-host resistance conferred by the inability of a host susceptibility factor to support viral multiplication may be a possible mechanism for this type of resistance to viruses.
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Affiliation(s)
- Cristina Nieto
- Centro de Edafología y Biología Aplicada del Segura (CEBAS), Consejo Superior de Investigaciones Científicas (CSIC), PO Box 164, 30100 Espinardo, Murcia, Spain
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Nicholson BL, Wu B, Chevtchenko I, White KA. Tombusvirus recruitment of host translational machinery via the 3' UTR. RNA (NEW YORK, N.Y.) 2010; 16:1402-19. [PMID: 20507975 PMCID: PMC2885689 DOI: 10.1261/rna.2135210] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
RNA viruses recruit the host translational machinery by different mechanisms that depend partly on the structure of their genomes. In this regard, the plus-strand RNA genomes of several different pathogenic plant viruses do not contain traditional translation-stimulating elements, i.e., a 5'-cap structure and a 3'-poly(A) tail, and instead rely on a 3'-cap-independent translational enhancer (3'CITE) located in their 3' untranslated regions (UTRs) for efficient synthesis of viral proteins. We investigated the structure and function of the I-shaped class of 3'CITE in tombusviruses--also present in aureusviruses and carmoviruses--using biochemical and molecular approaches and we determined that it adopts a complex higher-order RNA structure that facilitates translation by binding simultaneously to both eukaryotic initiation factor (eIF) 4F and the 5' UTR of the viral genome. The specificity of 3'CITE binding to eIF4F is mediated, at least in part, through a direct interaction with its eIF4E subunit, whereas its association with the viral 5' UTR relies on complementary RNA-RNA base-pairing. We show for the first time that this tripartite 5' UTR/3'CITE/eIF4F complex forms in vitro in a translationally relevant environment and is required for recruitment of ribosomes to the 5' end of the viral RNA genome by a mechanism that shares some fundamental features with cap-dependent translation. Notably, our results demonstrate that the 3'CITE facilitates the initiation step of translation and validate a molecular model that has been proposed to explain how several different classes of 3'CITE function. Moreover, the virus-host interplay defined in this study provides insights into natural host resistance mechanisms that have been linked to 3'CITE activity.
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Affiliation(s)
- Beth L Nicholson
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada
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Fraile A, García-Arenal F. The coevolution of plants and viruses: resistance and pathogenicity. Adv Virus Res 2010; 76:1-32. [PMID: 20965070 DOI: 10.1016/s0065-3527(10)76001-2] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Virus infection may damage the plant, and plant defenses are effective against viruses; thus, it is currently assumed that plants and viruses coevolve. However, and despite huge advances in understanding the mechanisms of pathogenicity and virulence in viruses and the mechanisms of virus resistance in plants, evidence in support of this hypothesis is surprisingly scant, and refers almost only to the virus partner. Most evidence for coevolution derives from the study of highly virulent viruses in agricultural systems, in which humans manipulate host genetic structure, what determines genetic changes in the virus population. Studies have focused on virus responses to qualitative resistance, either dominant or recessive but, even within this restricted scenario, population genetic analyses of pathogenicity and resistance factors are still scarce. Analyses of quantitative resistance or tolerance, which could be relevant for plant-virus coevolution, lag far behind. A major limitation is the lack of information on systems in which the host might evolve in response to virus infection, that is, wild hosts in natural ecosystems. It is presently unknown if, or under which circumstances, viruses do exert a selection pressure on wild plants, if qualitative resistance is a major defense strategy to viruses in nature, or even if characterized genes determining qualitative resistance to viruses did indeed evolve in response to virus infection. Here, we review evidence supporting plant-virus coevolution and point to areas in need of attention to understand the role of viruses in plant ecosystem dynamics, and the factors that determine virus emergence in crops.
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Affiliation(s)
- Aurora Fraile
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA) and E.T.S.I. Agrónomos, Universidad Politécnica de Madrid, Campus de Montegancedo, Pozuelo de Alarcón, Madrid, Spain
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Genovés A, Navarro JA, Pallás V. The Intra- and intercellular movement of Melon necrotic spot virus (MNSV) depends on an active secretory pathway. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:263-72. [PMID: 20121448 DOI: 10.1094/mpmi-23-3-0263] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Plant viruses hijack endogenous host transport machinery to aid their intracellular spread. Here, we study the localization of the p7B, the membrane-associated viral movement protein (MP) of the Melon necrotic spot virus (MNSV), and also the potential involvement of the secretory pathway on the p7B targeting and intra- and intercellular virus movements. p7B fused to fluorescent proteins was located throughout the endoplasmic reticulum (ER) at motile Golgi apparatus (GA) stacks that actively tracked the actin microfilaments, and at the plasmodesmata (PD). Hence, the secretory pathway inhibitor, Brefeldin A (BFA), and the overexpression of the GTPase-defective mutant of Sar1p, Sar1[H74L], fully retained the p7B within the ER, revealing that the protein is delivered to PD in a BFA-sensitive and COPII-dependent manner. Disruption of the actin cytoskeleton with latrunculin B led to the accumulation of p7B in the ER, which strongly suggests that p7B is also targeted to the cell periphery in an actin-dependent manner. Remarkably, the local spread of the viral infection was significantly restricted either with the presence of BFA or under the overexpression of Sar1[H74L], thus revealing the involvement of an active secretory pathway in the intracellular movement of MNSV. Overall, these findings support a novel route for the intracellular transport of a plant virus led by the GA.
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Affiliation(s)
- Ainhoa Genovés
- Instituto Biologia Molecular y Celular de Plantas, Universidad Politécnica, Universidad Politécnica de Valencia-CSIC, Avenida de los Naranjos s/n, 46022 Valencia, Spain
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Abstract
About half of the approximately 200 known virus resistance genes in plants are recessively inherited, suggesting that this form of resistance is more common for viruses than for other plant pathogens. The use of such genes is therefore a very important tool in breeding programs to control plant diseases caused by pathogenic viruses. Over the last few years, the detailed analysis of many host/virus combinations has substantially advanced basic research on recessive resistance mechanisms in crop species. This type of resistance is preferentially expressed in protoplasts and inoculated leaves, influencing virus multiplication at the single-cell level as well as cell-to-cell movement. Importantly, a growing number of recessive resistance genes have been cloned from crop species, and further analysis has shown them all to encode translation initiation factors of the 4E (eIF4E) and 4G (eIF4G) families. However, not all of the loss-of-susceptibility mutants identified in collections of mutagenized hosts correspond to mutations in eIF4E and eIF4G. This, together with other supporting data, suggests that more extensive characterization of the natural variability of resistance genes may identify new host factors conferring recessive resistance. In this chapter, we discuss the recent work carried out to characterize loss-of-susceptibility and recessive resistance genes in crop and model species. We review actual and probable recessive resistance mechanisms, and bring the chapter to a close by summarizing the current state-of-the-art and offering perspectives on potential future developments.
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Affiliation(s)
- V Truniger
- Centro de Edafología y Biología Aplicada del Segura (CEBAS), Consejo Superior de Investigaciones Científicas (CSIC), Apdo Correos 164, 30100 Espinardo (Murcia), Spain
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Genovés A, Navarro JA, Pallás V. A self-interacting carmovirus movement protein plays a role in binding of viral RNA during the cell-to-cell movement and shows an actin cytoskeleton dependent location in cell periphery. Virology 2009; 395:133-42. [PMID: 19796783 DOI: 10.1016/j.virol.2009.08.042] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 08/12/2009] [Accepted: 08/30/2009] [Indexed: 10/20/2022]
Abstract
The p7A of Melon necrotic spot virus has been described to be a RNA-binding movement protein essential for cell-to-cell movement but its role in this process is still unknown. Here, we found that primary and secondary structure elements on p7A appear to form a composite RNA-binding site required for both RNA interaction and cell-to-cell movement in plants indicating a direct correlation between these activities. Furthermore, we found that fluorescent-tagged p7A was distributed in punctuate structures at the cell periphery but also in motile cytoplasmic inclusion bodies which were in close association with the actin MFs and most likely generated by self-interacting p7A molecules as shown by BiFC assays. Consistently, the p7A subcellular distribution was revealed to be sensitive to the actin inhibitor, latrunculin B. The involvement of the RNA-binding capabilities and the subcellular location of the p7A in the intracellular and intercellular virus movement is discussed.
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Affiliation(s)
- Ainhoa Genovés
- Instituto de Biología Molecular y Celular de Plantas (IBMCP). UPV-CSIC, Avda. de los Naranjos s/n, Valencia, Spain.
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Janzac B, Fabre F, Palloix A, Moury B. Constraints on evolution of virus avirulence factors predict the durability of corresponding plant resistances. MOLECULAR PLANT PATHOLOGY 2009; 10:599-610. [PMID: 19694951 PMCID: PMC6640373 DOI: 10.1111/j.1364-3703.2009.00554.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
SUMMARY Understanding the factors driving pathogen emergence and re-emergence is a major challenge, particularly in agriculture, where the use of resistant plant cultivars imposes strong selective pressures on plant pathogen populations and leads frequently to 'resistance breakdown'. Presently, durable resistances are only identified after a long period of large-scale cultivation of resistant cultivars. We propose a new predictor of the durability of plant resistance. Because resistance breakdown involves modifications in the avirulence factors of pathogens, we tested for correlations between the evolutionary constraints acting on avirulence factors or their diversity and the durability of the corresponding resistance genes in the case of plant-virus interactions. An analysis performed on 20 virus species-resistance gene combinations revealed that the selective constraints applied on amino acid substitutions in virus avirulence factors correlate with the observed durability of the corresponding resistance genes. On the basis of this result, a model predicting the potential durability of resistance genes as a function of the selective constraints applied on the corresponding avirulence factors is proposed to help breeders to select the most durable resistance genes.
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Affiliation(s)
- Berenger Janzac
- INRA, UR407 Pathologie Végétale, Domaine Saint Maurice, BP94, F-84140 Montfavet, France.
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Mochizuki T, Hirai K, Kanda A, Ohnishi J, Ohki T, Tsuda S. Induction of necrosis via mitochondrial targeting of Melon necrotic spot virus replication protein p29 by its second transmembrane domain. Virology 2009; 390:239-49. [PMID: 19501870 DOI: 10.1016/j.virol.2009.05.012] [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] [Received: 02/19/2009] [Revised: 03/21/2009] [Accepted: 05/10/2009] [Indexed: 01/10/2023]
Abstract
The virulence factor of Melon necrotic spot virus (MNSV), a virus that induces systemic necrotic spot disease on melon plants, was investigated. When the replication protein p29 was expressed in N. benthamiana using a Cucumber mosaic virus vector, necrotic spots appeared on the leaf tissue. Transmission electron microscopy revealed abnormal mitochondrial aggregation in these tissues. Fractionation of tissues expressing p29 and confocal imaging using GFP-tagged p29 revealed that p29 associated with the mitochondrial membrane as an integral membrane protein. Expression analysis of p29 deletion fragments and prediction of hydrophobic transmembrane domains (TMDs) in p29 showed that deletion of the second putative TMD from p29 led to deficiencies in both the mitochondrial localization and virulence of p29. Taken together, these results indicated that MNSV p29 interacts with the mitochondrial membrane and that p29 may be a virulence factor causing the observed necrosis.
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Truniger V, Nieto C, González-Ibeas D, Aranda M. Mechanism of plant eIF4E-mediated resistance against a Carmovirus (Tombusviridae): cap-independent translation of a viral RNA controlled in cis by an (a)virulence determinant. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 56:716-27. [PMID: 18643998 DOI: 10.1111/j.1365-313x.2008.03630.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Translation initiation factors are universal determinants of plant susceptibility to RNA viruses, but the underlying mechanisms are poorly understood. Here, we show that a sequence in the 3' untranslated region (3'-UTR) of a viral genome that is responsible for overcoming plant eIF4E-mediated resistance (virulence determinant) functions as a 3' cap-independent translational enhancer (3'-CITE). The virus/plant pair studied here is Melon necrotic spot virus (MNSV) and melon, for which a recessive resistance controlled by melon eIF4E was previously described. Chimeric viruses between virulent and avirulent isolates enabled us to map the virulence and avirulence determinants to 49 and 26 nucleotides, respectively. The translational efficiency of a luc reporter gene flanked by 5'- and 3'-UTRs from virulent, avirulent and chimeric viruses was analysed in vitro, in wheatgerm extract, and in vivo, in melon protoplasts, showing that: (i) the virulence determinant mediates the efficient cap-independent translation in vitro and in vivo; (ii) the avirulence determinant was able to promote efficient cap-independent translation in vitro, but only when eIF4E from susceptible melon was added in trans, and, coherently, only in protoplasts of susceptible melon, but not in the protoplasts of resistant melon; (iii) these activities required the 5'-UTR of MNSV in cis. Thus, the virulence and avirulence determinants function as 3'-CITEs. The activity of these 3'-CITEs was host specific, suggesting that an inefficient interaction between the viral 3'-CITE of the avirulent isolate and eIF4E of resistant melon impedes the correct formation of the translation initiation complex at the viral RNA ends, thereby leading to resistance.
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Affiliation(s)
- Verónica Truniger
- Centro de Edafología y Biología Aplicada del Segura (CEBAS), Consejo Superior de Investigaciones Científicas (CSIC), Apdo. Correos 164, 30100 Espinardo, Murcia, Spain.
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Treder K, Kneller ELP, Allen EM, Wang Z, Browning KS, Miller WA. The 3' cap-independent translation element of Barley yellow dwarf virus binds eIF4F via the eIF4G subunit to initiate translation. RNA (NEW YORK, N.Y.) 2008; 14:134-47. [PMID: 18025255 PMCID: PMC2151041 DOI: 10.1261/rna.777308] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Accepted: 09/28/2007] [Indexed: 05/08/2023]
Abstract
The 3' cap-independent translation element (BTE) of Barley yellow dwarf virus RNA confers efficient translation initiation at the 5' end via long-distance base pairing with the 5'-untranslated region (UTR). Here we provide evidence that the BTE functions by recruiting translation initiation factor eIF4F. We show that the BTE interacts specifically with the cap-binding initiation factor complexes eIF4F and eIFiso4F in a wheat germ extract (wge). In wge depleted of cap-interacting factors, addition of eIF4F (and to a lesser extent, eIFiso4F) allowed efficient translation of an uncapped reporter construct (BLucB) containing the BTE in its 3' UTR. Translation of BLucB required much lower levels of eIF4F or eIFiso4F than did a capped, nonviral mRNA. Both full-length eIF4G and the carboxy-terminal half of eIF4G lacking the eIF4E binding site stimulated translation to 70% of the level obtained with eIF4F, indicating a minor role for the cap-binding protein, eIF4E. In wge inhibited by either BTE in trans or cap analog, eIF4G alone restored translation nearly as much as eIF4F, while addition of eIF4E alone had no effect. The BTE bound eIF4G (Kd = 177 nm) and eIF4F (Kd = 37 nm) with high affinity, but very weakly to eIF4E. These interactions correlate with the ability of the factors to facilitate BTE-mediated translation. These results and previous observations are consistent with a model in which eIF4F is delivered to the 5' UTR by the BTE, and they show that eIF4G, but not eIF4E, plays a major role in this novel mechanism of cap-independent translation.
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Affiliation(s)
- Krzysztof Treder
- Plant Pathology Department, Iowa State University, Ames, Iowa 50011, USA
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Gonzalez-Ibeas D, Blanca J, Roig C, González-To M, Picó B, Truniger V, Gómez P, Deleu W, Caño-Delgado A, Arús P, Nuez F, Garcia-Mas J, Puigdomènech P, Aranda MA. MELOGEN: an EST database for melon functional genomics. BMC Genomics 2007; 8:306. [PMID: 17767721 PMCID: PMC2034596 DOI: 10.1186/1471-2164-8-306] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Accepted: 09/03/2007] [Indexed: 11/22/2022] Open
Abstract
Background Melon (Cucumis melo L.) is one of the most important fleshy fruits for fresh consumption. Despite this, few genomic resources exist for this species. To facilitate the discovery of genes involved in essential traits, such as fruit development, fruit maturation and disease resistance, and to speed up the process of breeding new and better adapted melon varieties, we have produced a large collection of expressed sequence tags (ESTs) from eight normalized cDNA libraries from different tissues in different physiological conditions. Results We determined over 30,000 ESTs that were clustered into 16,637 non-redundant sequences or unigenes, comprising 6,023 tentative consensus sequences (contigs) and 10,614 unclustered sequences (singletons). Many potential molecular markers were identified in the melon dataset: 1,052 potential simple sequence repeats (SSRs) and 356 single nucleotide polymorphisms (SNPs) were found. Sixty-nine percent of the melon unigenes showed a significant similarity with proteins in databases. Functional classification of the unigenes was carried out following the Gene Ontology scheme. In total, 9,402 unigenes were mapped to one or more ontology. Remarkably, the distributions of melon and Arabidopsis unigenes followed similar tendencies, suggesting that the melon dataset is representative of the whole melon transcriptome. Bioinformatic analyses primarily focused on potential precursors of melon micro RNAs (miRNAs) in the melon dataset, but many other genes potentially controlling disease resistance and fruit quality traits were also identified. Patterns of transcript accumulation were characterised by Real-Time-qPCR for 20 of these genes. Conclusion The collection of ESTs characterised here represents a substantial increase on the genetic information available for melon. A database (MELOGEN) which contains all EST sequences, contig images and several tools for analysis and data mining has been created. This set of sequences constitutes also the basis for an oligo-based microarray for melon that is being used in experiments to further analyse the melon transcriptome.
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Affiliation(s)
- Daniel Gonzalez-Ibeas
- Departamento de Biología del Estrés y Patología Vegetal, Centro de Edafología y Biología Aplicada del Segura (CEBAS)- CSIC, Apdo. correos 164, 30100 Espinardo (Murcia), Spain
| | - José Blanca
- Departamento de Biotecnología, Instituto de Conservación y Mejora de la Agrodiversidad Valenciana (COMAV-UPV), Camino de Vera s/n, 46022 Valencia, Spain
| | - Cristina Roig
- Departamento de Biotecnología, Instituto de Conservación y Mejora de la Agrodiversidad Valenciana (COMAV-UPV), Camino de Vera s/n, 46022 Valencia, Spain
| | - Mireia González-To
- Departament de Genètica Vegetal, Centre de Recerca en Agrigenòmica CSIC-IRTA, Carretera de Cabrils Km2, 08348 Cabrils (Barcelona), Spain
| | - Belén Picó
- Departamento de Biotecnología, Instituto de Conservación y Mejora de la Agrodiversidad Valenciana (COMAV-UPV), Camino de Vera s/n, 46022 Valencia, Spain
| | - Verónica Truniger
- Departamento de Biología del Estrés y Patología Vegetal, Centro de Edafología y Biología Aplicada del Segura (CEBAS)- CSIC, Apdo. correos 164, 30100 Espinardo (Murcia), Spain
| | - Pedro Gómez
- Departamento de Biología del Estrés y Patología Vegetal, Centro de Edafología y Biología Aplicada del Segura (CEBAS)- CSIC, Apdo. correos 164, 30100 Espinardo (Murcia), Spain
| | - Wim Deleu
- Departament de Genètica Vegetal, Centre de Recerca en Agrigenòmica CSIC-IRTA, Carretera de Cabrils Km2, 08348 Cabrils (Barcelona), Spain
| | - Ana Caño-Delgado
- Departament de Genètica Molecular, Centre de Recerca en Agrigenòmica CSIC-IRTA, Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Pere Arús
- Departament de Genètica Vegetal, Centre de Recerca en Agrigenòmica CSIC-IRTA, Carretera de Cabrils Km2, 08348 Cabrils (Barcelona), Spain
| | - Fernando Nuez
- Departamento de Biotecnología, Instituto de Conservación y Mejora de la Agrodiversidad Valenciana (COMAV-UPV), Camino de Vera s/n, 46022 Valencia, Spain
| | - Jordi Garcia-Mas
- Departament de Genètica Vegetal, Centre de Recerca en Agrigenòmica CSIC-IRTA, Carretera de Cabrils Km2, 08348 Cabrils (Barcelona), Spain
| | - Pere Puigdomènech
- Departament de Genètica Molecular, Centre de Recerca en Agrigenòmica CSIC-IRTA, Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Miguel A Aranda
- Departamento de Biología del Estrés y Patología Vegetal, Centro de Edafología y Biología Aplicada del Segura (CEBAS)- CSIC, Apdo. correos 164, 30100 Espinardo (Murcia), Spain
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Nieto C, Piron F, Dalmais M, Marco CF, Moriones E, Gómez-Guillamón ML, Truniger V, Gómez P, Garcia-Mas J, Aranda MA, Bendahmane A. EcoTILLING for the identification of allelic variants of melon eIF4E, a factor that controls virus susceptibility. BMC PLANT BIOLOGY 2007; 7:34. [PMID: 17584936 PMCID: PMC1914064 DOI: 10.1186/1471-2229-7-34] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Accepted: 06/21/2007] [Indexed: 05/15/2023]
Abstract
BACKGROUND Translation initiation factors of the 4E and 4G protein families mediate resistance to several RNA plant viruses in the natural diversity of crops. Particularly, a single point mutation in melon eukaryotic translation initiation factor 4E (eIF4E) controls resistance to Melon necrotic spot virus (MNSV) in melon. Identification of allelic variants within natural populations by EcoTILLING has become a rapid genotype discovery method. RESULTS A collection of Cucumis spp. was characterised for susceptibility to MNSV and Cucumber vein yellowing virus (CVYV) and used for the implementation of EcoTILLING to identify new allelic variants of eIF4E. A high conservation of eIF4E exonic regions was found, with six polymorphic sites identified out of EcoTILLING 113 accessions. Sequencing of regions surrounding polymorphisms revealed that all of them corresponded to silent nucleotide changes and just one to a non-silent change correlating with MNSV resistance. Except for the MNSV case, no correlation was found between variation of eIF4E and virus resistance, suggesting the implication of different and/or additional genes in previously identified resistance phenotypes. We have also characterized a new allele of eIF4E from Cucumis zeyheri, a wild relative of melon. Functional analyses suggested that this new eIF4E allele might be responsible for resistance to MNSV. CONCLUSION This study shows the applicability of EcoTILLING in Cucumis spp., but given the conservation of eIF4E, new candidate genes should probably be considered to identify new sources of resistance to plant viruses. Part of the methodology described here could alternatively be used in TILLING experiments that serve to generate new eIF4E alleles.
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Affiliation(s)
- Cristina Nieto
- Centro de Edafología y Biología Aplicada del Segura (CEBAS)- CSIC, Apdo. correos 164, 30100 Espinardo, Murcia, Spain
- Unité de Recherche en Génomique Végétale (INRA-URGV), 2, rue Gaston Crémieux CP 5708, 91057 Evry Cedex, France
| | - Florence Piron
- Unité de Recherche en Génomique Végétale (INRA-URGV), 2, rue Gaston Crémieux CP 5708, 91057 Evry Cedex, France
| | - Marion Dalmais
- Unité de Recherche en Génomique Végétale (INRA-URGV), 2, rue Gaston Crémieux CP 5708, 91057 Evry Cedex, France
| | - Cristina F Marco
- Estación Experimental La Mayora (EELM)- CSIC, 29750 Algarrobo-Costa, Málaga, Spain
| | - Enrique Moriones
- Estación Experimental La Mayora (EELM)- CSIC, 29750 Algarrobo-Costa, Málaga, Spain
| | | | - Verónica Truniger
- Centro de Edafología y Biología Aplicada del Segura (CEBAS)- CSIC, Apdo. correos 164, 30100 Espinardo, Murcia, Spain
| | - Pedro Gómez
- Centro de Edafología y Biología Aplicada del Segura (CEBAS)- CSIC, Apdo. correos 164, 30100 Espinardo, Murcia, Spain
| | - Jordi Garcia-Mas
- Departament de Genètica Vegetal, Laboratori de Genètica Molecular Vegetal CSIC-IRTA, carretera de Cabrils s/n, 08348 Cabrils, Barcelona, Spain
| | - Miguel A Aranda
- Centro de Edafología y Biología Aplicada del Segura (CEBAS)- CSIC, Apdo. correos 164, 30100 Espinardo, Murcia, Spain
| | - Abdelhafid Bendahmane
- Unité de Recherche en Génomique Végétale (INRA-URGV), 2, rue Gaston Crémieux CP 5708, 91057 Evry Cedex, France
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38
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Margaria P, Ciuffo M, Pacifico D, Turina M. Evidence that the nonstructural protein of Tomato spotted wilt virus is the avirulence determinant in the interaction with resistant pepper carrying the TSW gene. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2007; 20:547-58. [PMID: 17506332 DOI: 10.1094/mpmi-20-5-0547] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
All known pepper cultivars resistant to Tomato spotted wilt virus (TSWV) possess a single dominant resistance gene, Tsw. Recently, naturally occurring resistance-breaking (RB) TSWV strains have been identified, causing major concerns. We used a collection of such strains to identify the specific genetic determinant that allows the virus to overcome the Tsw gene in Capsicum spp. A reverse genetic approach is still not feasible for TSWV; therefore, we analyzed reassortants between wild-type (WT) and RB strains. Our results confirmed that the S RNA, which encodes both the nucleocapsid protein (N) and a nonstructural protein (NSs), carries the genetic determinant responsible for Tsw resistance breakdown. We then used full-length S RNA segments or the proteins they encode to compare the sequences of WT and related RB strains, and obtained indirect evidence that the NSs protein is the avirulence factor in question. Transient expression of NSs protein from WT and RB strains showed that they both can equally suppress post-transcriptional gene silencing (PTGS). Moreover, biological characterization of two RB strains carrying deletions in the NSs protein showed that NSs is important in maintaining TSWV infection in newly emerging leaves over time, preventing recovery. Analysis of another RB strain phenotype allowed us to conclude that local necrotic response is not sufficient for resistance in Capsicum spp. carrying the Tsw gene.
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Affiliation(s)
- P Margaria
- Istituto di Virologia Vegetale, Sez. di Torino, CNR, Strada delle Cacce 73, Torino 10135, Italy
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Maule AJ, Caranta C, Boulton MI. Sources of natural resistance to plant viruses: status and prospects. MOLECULAR PLANT PATHOLOGY 2007; 8:223-31. [PMID: 20507494 DOI: 10.1111/j.1364-3703.2007.00386.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
SUMMARY Globally, virus diseases are common in agricultural crops and have a major agronomic impact. They are countered through the deployment of genetic resistance against the virus, or through the use of a range of farming practices based upon the propagation of virus-free plant material and the exclusion of the virus vectors from the growing crop. We review here the current status of our knowledge of natural virus resistance genes, and consider the future prospects for the deployment of these genes against virus infection.
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Affiliation(s)
- Andrew J Maule
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, UK
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40
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Nieto C, Morales M, Orjeda G, Clepet C, Monfort A, Sturbois B, Puigdomènech P, Pitrat M, Caboche M, Dogimont C, Garcia-Mas J, Aranda MA, Bendahmane A. An eIF4E allele confers resistance to an uncapped and non-polyadenylated RNA virus in melon. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2006; 48:452-62. [PMID: 17026540 DOI: 10.1111/j.1365-313x.2006.02885.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The characterization of natural recessive resistance genes and virus-resistant mutants of Arabidopsis have implicated translation initiation factors of the 4E family [eIF4E and eIF(iso)4E] as susceptibility factors required for virus multiplication and resistance expression. To date, viruses controlled by these genes mainly belong to the family Potyviridae. Melon necrotic spot virus (MNSV) belongs to the family Tombusviridae (genus Carmovirus) and is an uncapped and non-polyadenylated RNA virus. In melon, nsv-mediated resistance is a natural source of recessive resistance against all strains of MNSV except MNSV-264. Analyses of chimeras between non-resistance-breaking and resistance-breaking strains have shown that the avirulence determinant maps to the 3'-untranslated region (3'-UTR) of the viral genome. Using a combination of positional cloning and microsynteny analysis between Arabidopsis thaliana and melon, we genetically and physically delimited the nsv locus to a single bacterial artificial chromosome clone and identified the melon eukaryotic translation initiation factor 4E (Cm-eIF4E) as a candidate gene. Complementation analysis using a biolistic transient expression assay, confirmed Cm-eIF4E as the product of nsv. A single amino acid change at position 228 of the protein led to the resistance to MNSV. Protein expression and cap-binding analysis showed that Cm-eIF4E encoded by a resistant plant was not affected in it's cap-binding activity. The Agrobacterium-mediated transient expression of the susceptibility allele of Cm-eIF4E in Nicotiana benthamiana enhanced MNSV-264 accumulation. Based on these results, a model to explain melon resistance to MNSV is proposed. These data, and data from other authors, suggest that translation initiation factors of the eIF4E family are universal determinants of plant susceptibility to RNA viruses.
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Affiliation(s)
- Cristina Nieto
- Centro de Edafología y Biología Aplicada del Segura (CEBAS)- CSIC, Apdo. correos 164, 30100 Espinardo, Murcia, Spain
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Genovés A, Navarro JA, Pallás V. Functional analysis of the five melon necrotic spot virus genome-encoded proteins. J Gen Virol 2006; 87:2371-2380. [PMID: 16847133 DOI: 10.1099/vir.0.81793-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Function of the melon necrotic spot virus (MNSV) genome-encoded proteins (p29, p89, p7A, p7B and p42) has been studied. Protein-expression mutants of an infectious, full-length cDNA clone of a Spanish MNSV-Al isolate and a recombinant green fluorescent protein (GFP)-expressing virus were used in infection bioassays on melon plants. Results revealed that p29 and p89 are both essential for virus replication, whereas small proteins p7A and p7B are sufficient to support viral movement between adjacent cells operating in trans. It is also demonstrated that, in addition to its structural role as coat protein, p42 is an important factor controlling symptoms and is required for systemic transport. Moreover, both p42 and p7B, among all of the MNSV-encoded proteins, were able to delay RNA silencing in transient-expression assays on GFP-transgenic Nicotiana benthamiana plants. Finally, the presence of p42 also produced an enhancing effect on local spread similar to that of potyviral helper component proteinase (HC-Pro), probably due to its RNA silencing-suppression ability.
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Affiliation(s)
- A Genovés
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), UPV-CSIC, Avda de los Naranjos s/n, 46022 Valencia, Spain
| | - J A Navarro
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), UPV-CSIC, Avda de los Naranjos s/n, 46022 Valencia, Spain
| | - V Pallás
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), UPV-CSIC, Avda de los Naranjos s/n, 46022 Valencia, Spain
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42
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Robaglia C, Caranta C. Translation initiation factors: a weak link in plant RNA virus infection. TRENDS IN PLANT SCIENCE 2006; 11:40-5. [PMID: 16343979 DOI: 10.1016/j.tplants.2005.11.004] [Citation(s) in RCA: 275] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Revised: 10/11/2005] [Accepted: 11/25/2005] [Indexed: 05/05/2023]
Abstract
Recessive resistance genes against plant viruses have been recognized for a long time but their molecular nature has only recently been linked to components of the eukaryotic translation initiation complex. Translation initiation factors, and particularly the eIF4E and eIF4G protein families, were found to be essential determinants in the outcome of RNA virus infections. Viruses affected by these genes belong mainly to potyviruses; natural viral resistance mechanisms as well as mutagenesis analysis in Arabidopsis all converged to identify the same set of translation initiation factors. Their role in plant resistance against RNA viruses remains to be elucidated. Although the interaction with the protein synthesis machinery is probably a key element for successful RNA virus infection, other possible mechanisms will also be discussed.
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Affiliation(s)
- Christophe Robaglia
- Laboratoire de Génétique et Biophysique des Plantes, CEA-CNRS-Université Aix-Marseille II, Faculté des Sciences de Luminy, F-13009 Marseille, France.
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Morales M, Orjeda G, Nieto C, van Leeuwen H, Monfort A, Charpentier M, Caboche M, Arús P, Puigdomènech P, Aranda MA, Dogimont C, Bendahmane A, Garcia-Mas J. A physical map covering the nsv locus that confers resistance to Melon necrotic spot virus in melon (Cucumis melo L.). TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2005; 111:914-22. [PMID: 16052354 DOI: 10.1007/s00122-005-0019-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2005] [Accepted: 06/14/2005] [Indexed: 05/03/2023]
Abstract
Melon necrotic spot virus (MNSV) is a member of the genus Carmovirus, which produces severe yield losses in melon and cucumber crops. The nsv gene is the only known natural source of resistance against MNSV in melon, and confers protection against all widespread strains of this virus. nsv has been previously mapped in melon linkage group 11, in a region spanning 5.9 cM, saturated with RAPD and AFLP markers. To identify the nsv gene by positional cloning, we started construction of a high-resolution map for this locus. On the basis of the two mapping populations, F(2) and BC1, which share the same resistant parent PI 161375 (nsv/nsv), and using more than 3,000 offspring, a high-resolution genetic map has been constructed in the region around the nsv locus, spanning 3.2 cM between CAPS markers M 29 and M 132. The availability of two melon BAC libraries allowed for screening and the identification of new markers closer to the resistance gene, by means of BAC-end sequencing and mapping. We constructed a BAC contig in this region and identified the marker 52 K 20 sp 6, which co-segregates with nsv in 408 F(2) and 2.727 BC1 individuals in both mapping populations. We also identified a single 100 kb BAC that physically contains the resistance gene and covers a genetic distance of 0.73 cM between both BAC ends. These are the basis for the isolation of the nsv recessive-resistance gene.
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Affiliation(s)
- Mónica Morales
- Departament de Genètica Vegetal, Laboratori de Genètica Molecular Vegetal CSIC-IRTA, carretera de Cabrils s/n, 08348 Cabrils (Barcelona), Spain
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Skamnioti P, Ridout CJ. Microbial avirulence determinants: guided missiles or antigenic flak? MOLECULAR PLANT PATHOLOGY 2005; 6:551-559. [PMID: 20565679 DOI: 10.1111/j.1364-3703.2005.00302.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
SUMMARY Avirulence (avr) determinants are incompatibility factors which elicit host plant defence responses in a gene-for-gene manner. They are produced by fungi, bacteria and viruses, and their recognition by resistance genes has been extensively studied for decades. But why should a microbe keep a molecule that allows it to be recognized? One argument is that avr genes perform some essential function and must be kept despite giving the pathogen away. Many bacterial avr determinants have been shown to be effectors, which contribute to virulence and aggressiveness. If this were always the case, mutants lacking these essential molecules would be at a serious disadvantage. Some disadvantage has been shown for a small number, but for the majority there is no effect on virulence. This has been explained by functional redundancy for bacterial and fungal avr determinants, with other molecules compensating for the deletion of these essential genes. However, this argument is counter-intuitive because by definition these individual genes are no longer essential; so why keep them? With increasing numbers of avr genes being identified, efforts to elucidate their function are increasing. In this review, we take stock of the accumulating literature, and consider what the real function of avr determinants might be.
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Affiliation(s)
- Paraskevi Skamnioti
- Department of Disease and Stress Biology, John Innes Centre, Norwich Research Park, Colney Lane, Norwich NR4 7UH, UK
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Marco CF, Aranda MA. Genetic diversity of a natural population of Cucurbit yellow stunting disorder virus. J Gen Virol 2005; 86:815-822. [PMID: 15722544 DOI: 10.1099/vir.0.80584-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
An analysis of nucleotide sequences in five coding and one non-coding genomic regions of 35Cucurbit yellow stunting disorder virus(CYSDV) isolates collected on a local scale over an 8 year period is reported here. In total, 2277 nt were sequenced for each isolate, representing about 13 % of the complete virus genome. Mean nucleotide diversity for the whole population in synonymous positions in the coding regions was 0·00068, whilst in the 5′ untranslated region (5′ UTR) of genomic RNA2, it was 0·00074; both of these values are very small, compared with estimates of nucleotide diversity for populations of other plant viruses. Nucleotide diversity was also determined independently for each of the ORFs and for the 5′ UTR of RNA2; the data showed that variability is not distributed evenly among the different regions of the viral genome, with the coat protein gene showing more diversity than the other four coding regions that were analysed. However, the low variability found precluded any inference of selection differences among gene regions. On the other hand, no evidence of selection associated with host adaptation was found. In contrast, at least a single amino acid change in the coat protein appears to have been selected with time.
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Affiliation(s)
- C F Marco
- Estación Experimental 'La Mayora', Consejo Superior de Investigaciones Científicas, 29750 Algarrobo-Costa, Málaga, Spain
| | - M A Aranda
- Centro de Edafología y Biología Aplicada del Segura (CEBAS), Consejo Superior de Investigaciones Científicas, Campus Universitario de Espinardo, Apdo Correos 164, 30100 Espinardo, Murcia, Spain
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Abstract
Genetic resistance to plant viruses has been used for at least 80 years to control agricultural losses to viral diseases. To date, hundreds of naturally occurring genes for resistance to plant viruses have been reported from studies of both monocot and dicot crops, their wild relatives, and the plant model, Arabidopsis. The isolation and characterization of a few of these genes in the past decade have resulted in detailed knowledge of some of the molecules that are critical in determining the outcome of plant viral infection. In this chapter, we have catalogued genes for resistance to plant viruses and have summarized current knowledge regarding their identity and inheritance. Insofar as information is available, the genetic context, genomic organization, mechanisms of resistance and agricultural deployment of plant virus resistance genes are also discussed.
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Affiliation(s)
- Byoung-Cheorl Kang
- Department of Plant Breeding and Genetics, Cornell University, Ithaca, New York 14853, USA.
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