1
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Mbewe W, Mukasa S, Ochwo-Ssemakula M, Sseruwagi P, Tairo F, Ndunguru J, Duffy S. Cassava brown streak virus evolves with a nucleotide-substitution rate that is typical for the family Potyviridae. Virus Res 2024; 346:199397. [PMID: 38750679 PMCID: PMC11145536 DOI: 10.1016/j.virusres.2024.199397] [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: 12/14/2023] [Revised: 05/08/2024] [Accepted: 05/12/2024] [Indexed: 05/25/2024]
Abstract
The ipomoviruses (family Potyviridae) that cause cassava brown streak disease (cassava brown streak virus [CBSV] and Uganda cassava brown streak virus [UCBSV]) are damaging plant pathogens that affect the sustainability of cassava production in East and Central Africa. However, little is known about the rate at which the viruses evolve and when they emerged in Africa - which inform how easily these viruses can host shift and resist RNAi approaches for control. We present here the rates of evolution determined from the coat protein gene (CP) of CBSV (Temporal signal in a UCBSV dataset was not sufficient for comparable analysis). Our BEAST analysis estimated the CBSV CP evolves at a mean rate of 1.43 × 10-3 nucleotide substitutions per site per year, with the most recent common ancestor of sampled CBSV isolates existing in 1944 (95% HPD, between years 1922 - 1963). We compared the published measured and estimated rates of evolution of CPs from ten families of plant viruses and showed that CBSV is an average-evolving potyvirid, but that members of Potyviridae evolve more quickly than members of Virgaviridae and the single representatives of Betaflexiviridae, Bunyaviridae, Caulimoviridae and Closteroviridae.
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Affiliation(s)
- Willard Mbewe
- Department of Biological Sciences, Malawi University of Science and Technology, P. O. Box 5196, Limbe, Malawi.
| | - Settumba Mukasa
- School of Agriculture and Environmental Science, Department of Agricultural Production, P. O. Box 7062, Makerere University, Kampala, Uganda
| | - Mildred Ochwo-Ssemakula
- School of Agriculture and Environmental Science, Department of Agricultural Production, P. O. Box 7062, Makerere University, Kampala, Uganda
| | - Peter Sseruwagi
- Mikocheni Agricultural Research Institute, P.O. Box 6226, Dar es Slaam, Tanzania
| | - Fred Tairo
- Mikocheni Agricultural Research Institute, P.O. Box 6226, Dar es Slaam, Tanzania
| | - Joseph Ndunguru
- Mikocheni Agricultural Research Institute, P.O. Box 6226, Dar es Slaam, Tanzania
| | - Siobain Duffy
- Department of Ecology, Evolution and Natural Resources, Rutgers University, New Brunswick, NJ 08901, United States.
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2
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Tamisier L, Fabre F, Szadkowski M, Chateau L, Nemouchi G, Girardot G, Millot P, Palloix A, Moury B. Within-plant genetic drift to control virus adaptation to host resistance genes. PLoS Pathog 2024; 20:e1012424. [PMID: 39102439 PMCID: PMC11326801 DOI: 10.1371/journal.ppat.1012424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 08/15/2024] [Accepted: 07/01/2024] [Indexed: 08/07/2024] Open
Abstract
Manipulating evolutionary forces imposed by hosts on pathogens like genetic drift and selection could avoid the emergence of virulent pathogens. For instance, increasing genetic drift could decrease the risk of pathogen adaptation through the random fixation of deleterious mutations or the elimination of favorable ones in the pathogen population. However, no experimental proof of this approach is available for a plant-pathogen system. We studied the impact of pepper (Capsicum annuum) lines carrying the same major resistance gene but contrasted genetic backgrounds on the evolution of Potato virus Y (PVY). The pepper lines were chosen for the contrasted levels of genetic drift (inversely related to Ne, the effective population size) they exert on PVY populations, as well as for their contrasted resistance efficiency (inversely related to the initial replicative fitness, Wi, of PVY in these lines). Experimental evolution was performed by serially passaging 64 PVY populations every month on six contrasted pepper lines during seven months. These PVY populations exhibited highly divergent evolutionary trajectories, ranging from viral extinctions to replicative fitness gains. The sequencing of the PVY VPg cistron, where adaptive mutations are likely to occur, allowed linking these replicative fitness gains to parallel adaptive nonsynonymous mutations. Evolutionary trajectories were well explained by the genetic drift imposed by the host. More specifically, Ne, Wi and their synergistic interaction played a major role in the fate of PVY populations. When Ne was low (i.e. strong genetic drift), the final PVY replicative fitness remained close to the initial replicative fitness, whereas when Ne was high (i.e. low genetic drift), the final PVY replicative fitness was high independently of the replicative fitness of the initially inoculated virus. We show that combining a high resistance efficiency (low Wi) and a strong genetic drift (low Ne) is the best solution to increase resistance durability, that is, to avoid virus adaptation on the long term.
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Affiliation(s)
- Lucie Tamisier
- INRAE, Pathologie Végétale, F-84140 Montfavet, France
- INRAE, Génétique et Amélioration des Fruits et Légumes, F-84143 Montfavet, France
| | | | - Marion Szadkowski
- INRAE, Pathologie Végétale, F-84140 Montfavet, France
- INRAE, Génétique et Amélioration des Fruits et Légumes, F-84143 Montfavet, France
| | - Lola Chateau
- INRAE, Pathologie Végétale, F-84140 Montfavet, France
| | - Ghislaine Nemouchi
- INRAE, Génétique et Amélioration des Fruits et Légumes, F-84143 Montfavet, France
| | | | | | - Alain Palloix
- INRAE, Génétique et Amélioration des Fruits et Légumes, F-84143 Montfavet, France
| | - Benoît Moury
- INRAE, Pathologie Végétale, F-84140 Montfavet, France
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3
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Gao M, Yang X, Wu Y, Wang J, Hu X, Ma Z, Zhou JH. Analysis for codon usage bias in membrane anchor of nonstructural protein 5A from BVDV. J Basic Microbiol 2023; 63:1106-1114. [PMID: 37407515 DOI: 10.1002/jobm.202300080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 05/23/2023] [Accepted: 06/02/2023] [Indexed: 07/07/2023]
Abstract
The nonstructural protein 5A (NS5A) of the bovine viral diarrhea virus (BVDV) is a monotopic membrane protein. This protein can anchor to the cell membrane by an in-plane amphipathic ⍺-helix, which participates in the viral replication complex. In this study, the effects of synonymous codon usage pattern of NS5A and the overall transfer RNA (tRNA) abundance in cells on the formation of the in-plane membrane anchor of NS5A were analyzed, based on NS5A coding sequences of different BVDV genotypes. BVDV NS5A coding sequences represent the most potential for BVDV genotyping. Moreover, the nucleotide usage of BVDV NS5A dominates the genotype-specific pattern of synonymous codon usage. There is an obvious relationship between synonymous codon usage bias and the spatial conformation of the in-plane membrane anchor. Furthermore, the overall tRNA abundance profiling displays that codon positions with a high level of tRNA abundance are more than ones with a low level of tRNA abundance in the in-plane membrane anchor, implying that high translation speed probably acts on the spatial conformation of in-plane membrane anchor of BVDV NS5A. These results give a new opinion on the effect of codon usage bias in the formation of the in-plane membrane anchor of BVDV NS5A.
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Affiliation(s)
- Mingyang Gao
- Key Laboratory of Biotechnology and Bioengineering of State Ethnic Affairs Commission, Biomedical Research Center, Northwest Minzu University, Lanzhou
- College of Life Science and Engineering, Northwest Minzu University, Lanzhou, Gansu, China
| | - Xuanye Yang
- Key Laboratory of Biotechnology and Bioengineering of State Ethnic Affairs Commission, Biomedical Research Center, Northwest Minzu University, Lanzhou
- College of Life Science and Engineering, Northwest Minzu University, Lanzhou, Gansu, China
| | - Yuhu Wu
- Key Laboratory of Biotechnology and Bioengineering of State Ethnic Affairs Commission, Biomedical Research Center, Northwest Minzu University, Lanzhou
- College of Life Science and Engineering, Northwest Minzu University, Lanzhou, Gansu, China
| | - Jinqian Wang
- Key Laboratory of Biotechnology and Bioengineering of State Ethnic Affairs Commission, Biomedical Research Center, Northwest Minzu University, Lanzhou
- College of Life Science and Engineering, Northwest Minzu University, Lanzhou, Gansu, China
| | - Xinyan Hu
- Key Laboratory of Biotechnology and Bioengineering of State Ethnic Affairs Commission, Biomedical Research Center, Northwest Minzu University, Lanzhou
- College of Life Science and Engineering, Northwest Minzu University, Lanzhou, Gansu, China
| | - Zhongren Ma
- Key Laboratory of Biotechnology and Bioengineering of State Ethnic Affairs Commission, Biomedical Research Center, Northwest Minzu University, Lanzhou
| | - Jian-Hua Zhou
- Key Laboratory of Biotechnology and Bioengineering of State Ethnic Affairs Commission, Biomedical Research Center, Northwest Minzu University, Lanzhou
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4
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Carvalho CP, Han J, Khemsom K, Ren R, Camargo LEA, Miyashita S, Qu F. Single-cell mutation rate of turnip crinkle virus (-)-strand replication intermediates. PLoS Pathog 2023; 19:e1011395. [PMID: 37578959 PMCID: PMC10449226 DOI: 10.1371/journal.ppat.1011395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 08/24/2023] [Accepted: 07/25/2023] [Indexed: 08/16/2023] Open
Abstract
Viruses with single-stranded, positive-sense (+) RNA genomes incur high numbers of errors during replication, thereby creating diversified genome populations from which new, better adapted viral variants can emerge. However, a definitive error rate is known for a relatively few (+) RNA plant viruses, due to challenges to account for perturbations caused by natural selection and/or experimental set-ups. To address these challenges, we developed a new approach that exclusively profiled errors in the (-)-strand replication intermediates of turnip crinkle virus (TCV), in singly infected cells. A series of controls and safeguards were devised to ensure errors inherent to the experimental process were accounted for. This approach permitted the estimation of a TCV error rate of 8.47 X 10-5 substitution per nucleotide site per cell infection. Importantly, the characteristic error distribution pattern among the 50 copies of 2,363-base-pair cDNA fragments predicted that nearly all TCV (-) strands were products of one replication cycle per cell. Furthermore, some of the errors probably elevated error frequencies by lowering the fidelity of TCV RNA-dependent RNA polymerase, and/or permitting occasional re-replication of progeny genomes. In summary, by profiling errors in TCV (-)-strand intermediates incurred during replication in single cells, this study provided strong support for a stamping machine mode of replication employed by a (+) RNA virus.
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Affiliation(s)
- Camila Perdoncini Carvalho
- Department of Plant Pathology, The Ohio State University, Wooster, Ohio, United States of America
- Department of Plant Pathology and Nematology, Luiz de Queiroz College of Agriculture, University of Sao Paolo, Piracicaba, Brazil
| | - Junping Han
- Department of Plant Pathology, The Ohio State University, Wooster, Ohio, United States of America
| | - Khwannarin Khemsom
- Department of Plant Pathology, The Ohio State University, Wooster, Ohio, United States of America
| | - Ruifan Ren
- Department of Plant Pathology, The Ohio State University, Wooster, Ohio, United States of America
- Longping Branch, College of Biology, Hunan University, Changsha, China
| | - Luis Eduardo Aranha Camargo
- Department of Plant Pathology and Nematology, Luiz de Queiroz College of Agriculture, University of Sao Paolo, Piracicaba, Brazil
| | - Shuhei Miyashita
- Graduate School of Agricultural Science, Tohoku University, Tohoku, Japan
| | - Feng Qu
- Department of Plant Pathology, The Ohio State University, Wooster, Ohio, United States of America
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5
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Mesel F, Zhao M, García B, Simón‐Mateo C, García J. Targeting of genomic and negative-sense strands of viral RNA contributes to antiviral resistance mediated by artificial miRNAs and promotes the emergence of complex viral populations. MOLECULAR PLANT PATHOLOGY 2022; 23:1640-1657. [PMID: 35989243 PMCID: PMC9562735 DOI: 10.1111/mpp.13258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 07/07/2022] [Accepted: 07/16/2022] [Indexed: 05/27/2023]
Abstract
Technology based on artificial small RNAs, including artificial microRNAs (amiRNAs), exploits natural RNA silencing mechanisms to achieve silencing of endogenous genes or pathogens. This technology has been successfully employed to generate resistance against different eukaryotic viruses. However, information about viral RNA molecules effectively targeted by these small RNAs is rather conflicting, and factors contributing to the selection of virus mutants escaping the antiviral activity of virus-specific small RNAs have not been studied in detail. In this work, we transformed Nicotiana benthamiana plants with amiRNA constructs designed against the potyvirus plum pox virus (PPV), a positive-sense RNA virus, and obtained lines highly resistant to PPV infection and others showing partial resistance. These lines have allowed us to verify that amiRNA directed against genomic RNA is more efficient than amiRNA targeting its complementary strand. However, we also provide evidence that the negative-sense RNA strand is cleaved by the amiRNA-guided RNA silencing machinery. Our results show that the selection pressure posed by the amiRNA action on both viral RNA strands causes an evolutionary explosion that results in the emergence of a broad range of virus variants, which can further expand in the presence, and even in the absence, of antiviral challenges.
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Affiliation(s)
- Frida Mesel
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología (CNB‐CSIC)Campus Universidad Autónoma de MadridMadridSpain
| | - Mingmin Zhao
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología (CNB‐CSIC)Campus Universidad Autónoma de MadridMadridSpain
- College of Horticulture and Plant ProtectionInner Mongolia Agricultural UniversityHohhotChina
| | - Beatriz García
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología (CNB‐CSIC)Campus Universidad Autónoma de MadridMadridSpain
| | - Carmen Simón‐Mateo
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología (CNB‐CSIC)Campus Universidad Autónoma de MadridMadridSpain
| | - Juan Antonio García
- Department of Plant Molecular Genetics, Centro Nacional de Biotecnología (CNB‐CSIC)Campus Universidad Autónoma de MadridMadridSpain
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6
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Abstract
Adaptive antiviral immunity in plants is an RNA-based mechanism in which small RNAs derived from both strands of the viral RNA are guides for an Argonaute (AGO) nuclease. The primed AGO specifically targets and silences the viral RNA. In plants this system has diversified to involve mobile small interfering RNAs (siRNAs), an amplification system involving secondary siRNAs and targeting mechanisms involving DNA methylation. Most, if not all, plant viruses encode multifunctional proteins that are suppressors of RNA silencing that may also influence the innate immune system and fine-tune the virus-host interaction. Animal viruses similarly trigger RNA silencing, although it may be masked in differentiated cells by the interferon system and by the action of the virus-encoded suppressor proteins. There is huge potential for RNA silencing to combat viral disease in crops, farm animals, and people, although there are complications associated with the various strategies for siRNA delivery including transgenesis. Alternative approaches could include using breeding or small molecule treatment to enhance the inherent antiviral capacity of infected cells.
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Affiliation(s)
- David C Baulcombe
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom;
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7
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Somovilla P, Rodríguez-Moreno A, Arribas M, Manrubia S, Lázaro E. Standing Genetic Diversity and Transmission Bottleneck Size Drive Adaptation in Bacteriophage Qβ. Int J Mol Sci 2022; 23:ijms23168876. [PMID: 36012143 PMCID: PMC9408265 DOI: 10.3390/ijms23168876] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/03/2022] [Accepted: 08/07/2022] [Indexed: 01/15/2023] Open
Abstract
A critical issue to understanding how populations adapt to new selective pressures is the relative contribution of the initial standing genetic diversity versus that generated de novo. RNA viruses are an excellent model to study this question, as they form highly heterogeneous populations whose genetic diversity can be modulated by factors such as the number of generations, the size of population bottlenecks, or exposure to new environment conditions. In this work, we propagated at nonoptimal temperature (43 °C) two bacteriophage Qβ populations differing in their degree of heterogeneity. Deep sequencing analysis showed that, prior to the temperature change, the most heterogeneous population contained some low-frequency mutations that had previously been detected in the consensus sequences of other Qβ populations adapted to 43 °C. Evolved populations with origin in this ancestor reached similar growth rates, but the adaptive pathways depended on the frequency of these standing mutations and the transmission bottleneck size. In contrast, the growth rate achieved by populations with origin in the less heterogeneous ancestor did depend on the transmission bottleneck size. The conclusion is that viral diversification in a particular environment may lead to the emergence of mutants capable of accelerating adaptation when the environment changes.
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Affiliation(s)
- Pilar Somovilla
- Centro de Astrobiología (CAB), CSIC-INTA, Ctra. de Torrejón Km 4, Torrejón de Ardoz, 28850 Madrid, Spain
| | - Alicia Rodríguez-Moreno
- Centro de Astrobiología (CAB), CSIC-INTA, Ctra. de Torrejón Km 4, Torrejón de Ardoz, 28850 Madrid, Spain
| | - María Arribas
- Centro de Astrobiología (CAB), CSIC-INTA, Ctra. de Torrejón Km 4, Torrejón de Ardoz, 28850 Madrid, Spain
| | - Susanna Manrubia
- Centro Nacional de Biotecnología (CNB-CSIC), c/Darwin 3, 28049 Madrid, Spain
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Madrid, Spain
| | - Ester Lázaro
- Centro de Astrobiología (CAB), CSIC-INTA, Ctra. de Torrejón Km 4, Torrejón de Ardoz, 28850 Madrid, Spain
- Correspondence:
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8
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Mongelli V, Lequime S, Kousathanas A, Gausson V, Blanc H, Nigg J, Quintana-Murci L, Elena SF, Saleh MC. Innate immune pathways act synergistically to constrain RNA virus evolution in Drosophila melanogaster. Nat Ecol Evol 2022; 6:565-578. [PMID: 35273366 PMCID: PMC7612704 DOI: 10.1038/s41559-022-01697-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 12/14/2021] [Indexed: 02/05/2023]
Abstract
Host-pathogen interactions impose recurrent selective pressures that lead to constant adaptation and counter-adaptation in both competing species. Here, we sought to study this evolutionary arms-race and assessed the impact of the innate immune system on viral population diversity and evolution, using Drosophila melanogaster as model host and its natural pathogen Drosophila C virus (DCV). We isogenized eight fly genotypes generating animals defective for RNAi, Imd and Toll innate immune pathways as well as pathogen-sensing and gut renewal pathways. Wild-type or mutant flies were then orally infected with DCV and the virus was serially passaged ten times via reinfection in naive flies. Viral population diversity was studied after each viral passage by high-throughput sequencing and infection phenotypes were assessed at the beginning and at the end of the evolution experiment. We found that the absence of any of the various immune pathways studied increased viral genetic diversity while attenuating virulence. Strikingly, these effects were observed in a range of host factors described as having mainly antiviral or antibacterial functions. Together, our results indicate that the innate immune system as a whole and not specific antiviral defence pathways in isolation, generally constrains viral diversity and evolution.
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Affiliation(s)
- Vanesa Mongelli
- Viruses and RNA Interference Unit, Institut Pasteur, CNRS, Paris, France
| | - Sebastian Lequime
- Cluster of Microbial Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | | | - Valérie Gausson
- Viruses and RNA Interference Unit, Institut Pasteur, CNRS, Paris, France
| | - Hervé Blanc
- Viruses and RNA Interference Unit, Institut Pasteur, CNRS, Paris, France
| | - Jared Nigg
- Viruses and RNA Interference Unit, Institut Pasteur, CNRS, Paris, France
| | - Lluis Quintana-Murci
- Human Evolutionary Genetic Unit, Institut Pasteur, CNRS, Paris, France
- Human Genomics and Evolution, Collège de France, Paris, France
| | - Santiago F Elena
- Instituto de Biología Integrativa de Sistemas (CSIC-Universitat de València), València, Spain.
- The Santa Fe Institute, Santa Fe, NM, USA.
| | - Maria-Carla Saleh
- Viruses and RNA Interference Unit, Institut Pasteur, CNRS, Paris, France.
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9
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Carbonell A. RNAi tools for controlling viroid diseases. Virus Res 2022; 313:198729. [DOI: 10.1016/j.virusres.2022.198729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/02/2022] [Accepted: 03/05/2022] [Indexed: 12/01/2022]
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10
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Moyo L, Raikhy G, Hamid A, Mallik I, Gudmestad NC, Gray S, Pappu HR. Phylogenetics of tobacco rattle virus isolates from potato (Solanum tuberosum L.) in the USA: a multi-gene approach to evolutionary lineage. Virus Genes 2022; 58:42-52. [PMID: 34671909 DOI: 10.1007/s11262-021-01875-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 10/05/2021] [Indexed: 01/22/2023]
Abstract
Tobacco rattle virus (TRV) is an important soil-borne virus of potato that is transmitted by stubby-root nematodes. TRV causes corky ringspot, a tuber disease of economic importance to potato production. Utilizing protein-coding regions of the whole genome and a range of computational tools, the genetic diversity, and population structure of TRV isolates from several potato-growing regions (Colorado, Idaho, Indiana, Minnesota, Nebraska, North Dakota, and Washington State) in the USA were determined. Phylogenetic analyses based on RNA2 nucleotide sequences, the coat protein (CP) and nematode transmission (2b) genes, showed geographical clustering of USA isolates with previously known American isolates, while European isolates grouped in a distinct cluster. This was corroborated by the observed genetic differentiation and infrequent gene flow between American and European isolates. Low genetic diversity was revealed among American isolates compared to European isolates. Phylogenetic clustering based on RNA1 genes (RdRp, RdRp-RT, and 1a) were all largely incongruent to that of 1b gene (virus suppressor of RNA silencing). This genetic incongruence suggested the influence of recombination. Furthermore, the RdRp, RdRp-RT, and 1a genes were predicted to be more conserved and under negative selection, while the 1b gene was less constrained. Different evolutionary lineages between TRV RNA1 and RNA2 genomic segments were revealed.
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Affiliation(s)
- Lindani Moyo
- Department of Plant Pathology, Washington State University, Pullman, WA, 99164, USA
- Molecular Plant Sciences Graduate Program, Washington State University, Pullman, WA, 99164, USA
- Department of Environmental Science and Health, National University of Science and Technology, PO Box AC939, Ascot, Bulawayo, Zimbabwe
- Department of Plant Pathology, Stellenbosch University, Private Bag X1, Matieland, Stellenbosch, 7600, South Africa
| | - Gaurav Raikhy
- Department of Plant Pathology, Washington State University, Pullman, WA, 99164, USA
| | - Aflaq Hamid
- Department of Plant Pathology, Washington State University, Pullman, WA, 99164, USA
| | - Ipsita Mallik
- Department of Plant Pathology, North Dakota State University, Fargo, ND, 58108, USA
| | - Neil C Gudmestad
- Department of Plant Pathology, North Dakota State University, Fargo, ND, 58108, USA
| | - Stewart Gray
- Section of Plant Pathology and Plant-Microbe Biology, School of Plant Science, Cornell University, Ithaca, NY, 14853, USA
| | - Hanu R Pappu
- Department of Plant Pathology, Washington State University, Pullman, WA, 99164, USA.
- Molecular Plant Sciences Graduate Program, Washington State University, Pullman, WA, 99164, USA.
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11
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Palukaitis P, Kim S. Resistance to Turnip Mosaic Virus in the Family Brassicaceae. THE PLANT PATHOLOGY JOURNAL 2021; 37:1-23. [PMID: 33551693 PMCID: PMC7847761 DOI: 10.5423/ppj.rw.09.2020.0178] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/30/2020] [Accepted: 11/30/2020] [Indexed: 05/21/2023]
Abstract
Resistance to diseases caused by turnip mosaic virus (TuMV) in crop species of the family Brassicaceae has been studied extensively, especially in members of the genus Brassica. The variation in response observed on resistant and susceptible plants inoculated with different isolates of TuMV is due to a combination of the variation in the plant resistome and the variation in the virus genome. Here, we review the breadth of this variation, both at the level of variation in TuMV sequences, with one eye towards the phylogeny and evolution of the virus, and another eye towards the nature of the various responses observed in susceptible vs. different types of resistance responses. The analyses of the viral genomes allowed comparisons of pathotyped viruses on particular indicator hosts to produce clusters of host types, while the inclusion of phylogeny data and geographic location allowed the formation of the host/geographic cluster groups, the derivation of both of which are presented here. Various studies on resistance determination in particular brassica crops sometimes led to further genetic studies, in many cases to include the mapping of genes, and in some cases to the actual identification of the genes. In addition to summarizing the results from such studies done in brassica crops, as well as in radish and Arabidopsis (the latter as a potential source of candidate genes for brassica and radish), we also summarize work done using nonconventional approaches to obtaining resistance to TuMV.
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Affiliation(s)
- Peter Palukaitis
- Department of Horticultural Sciences, Seoul Women’s University, Seoul 0797, Korea
- Co-corresponding authors P. Palukaitis, Phone) +82-2-970-5614, FAX) +82-2-970-5610, E-mail) , S. Kim, Phone) +82-31-5182-8112, FAX) +82-31-5182-8113, E-mail) , ORCID, Peter Palukaitis https://orcid.org/0000-0001-8735-1273
| | - Su Kim
- Institute of Plant Analysis Technology Development, The Saeron Co., Suwon 16648, Korea
- Co-corresponding authors P. Palukaitis, Phone) +82-2-970-5614, FAX) +82-2-970-5610, E-mail) , S. Kim, Phone) +82-31-5182-8112, FAX) +82-31-5182-8113, E-mail) , ORCID, Peter Palukaitis https://orcid.org/0000-0001-8735-1273
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12
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Cisneros AE, Carbonell A. Artificial Small RNA-Based Silencing Tools for Antiviral Resistance in Plants. PLANTS 2020; 9:plants9060669. [PMID: 32466363 PMCID: PMC7356032 DOI: 10.3390/plants9060669] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 01/05/2023]
Abstract
Artificial small RNAs (art-sRNAs), such as artificial microRNAs (amiRNAs) and synthetic trans-acting small interfering RNAs (syn-tasiRNAs), are highly specific 21-nucleotide small RNAs designed to recognize and silence complementary target RNAs. Art-sRNAs are extensively used in gene function studies or for improving crops, particularly to protect plants against viruses. Typically, antiviral art-sRNAs are computationally designed to target one or multiple sites in viral RNAs with high specificity, and art-sRNA constructs are generated and introduced into plants that are subsequently challenged with the target virus(es). Numerous studies have reported the successful application of art-sRNAs to induce resistance against a large number of RNA and DNA viruses in model and crop species. However, the application of art-sRNAs as an antiviral tool has limitations, such as the difficulty to predict the efficacy of a particular art-sRNA or the emergence of virus variants with mutated target sites escaping to art-sRNA-mediated degradation. Here, we review the different classes, features, and uses of art-sRNA-based tools to induce antiviral resistance in plants. We also provide strategies for the rational design of antiviral art-sRNAs and discuss the latest advances in developing art-sRNA-based methodologies for enhanced resistance to plant viruses.
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13
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Abstract
Genetic variation is a necessity of all biological systems. Viruses use all known mechanisms of variation; mutation, several forms of recombination, and segment reassortment in the case of viruses with a segmented genome. These processes are intimately connected with the replicative machineries of viruses, as well as with fundamental physical-chemical properties of nucleotides when acting as template or substrate residues. Recombination has been viewed as a means to rescue viable genomes from unfit parents or to produce large modifications for the exploration of phenotypic novelty. All types of genetic variation can act conjointly as blind processes to provide the raw materials for adaptation to the changing environments in which viruses must replicate. A distinction is made between mechanistically unavoidable and evolutionarily relevant mutation and recombination.
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Rubio L, Galipienso L, Ferriol I. Detection of Plant Viruses and Disease Management: Relevance of Genetic Diversity and Evolution. FRONTIERS IN PLANT SCIENCE 2020; 11:1092. [PMID: 32765569 PMCID: PMC7380168 DOI: 10.3389/fpls.2020.01092] [Citation(s) in RCA: 110] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 07/02/2020] [Indexed: 05/04/2023]
Abstract
Plant viruses cause considerable economic losses and are a threat for sustainable agriculture. The frequent emergence of new viral diseases is mainly due to international trade, climate change, and the ability of viruses for rapid evolution. Disease control is based on two strategies: i) immunization (genetic resistance obtained by plant breeding, plant transformation, cross-protection, or others), and ii) prophylaxis to restrain virus dispersion (using quarantine, certification, removal of infected plants, control of natural vectors, or other procedures). Disease management relies strongly on a fast and accurate identification of the causal agent. For known viruses, diagnosis consists in assigning a virus infecting a plant sample to a group of viruses sharing common characteristics, which is usually referred to as species. However, the specificity of diagnosis can also reach higher taxonomic levels, as genus or family, or lower levels, as strain or variant. Diagnostic procedures must be optimized for accuracy by detecting the maximum number of members within the group (sensitivity as the true positive rate) and distinguishing them from outgroup viruses (specificity as the true negative rate). This requires information on the genetic relationships within-group and with members of other groups. The influence of the genetic diversity of virus populations in diagnosis and disease management is well documented, but information on how to integrate the genetic diversity in the detection methods is still scarce. Here we review the techniques used for plant virus diagnosis and disease control, including characteristics such as accuracy, detection level, multiplexing, quantification, portability, and designability. The effect of genetic diversity and evolution of plant viruses in the design and performance of some detection and disease control techniques are also discussed. High-throughput or next-generation sequencing provides broad-spectrum and accurate identification of viruses enabling multiplex detection, quantification, and the discovery of new viruses. Likely, this technique will be the future standard in diagnostics as its cost will be dropping and becoming more affordable.
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Affiliation(s)
- Luis Rubio
- Centro de Protección Vegetal y Biotecnology, Instituto Valenciano de Investigaciones Agrarias, Moncada, Spain
- *Correspondence: Luis Rubio,
| | - Luis Galipienso
- Centro de Protección Vegetal y Biotecnology, Instituto Valenciano de Investigaciones Agrarias, Moncada, Spain
| | - Inmaculada Ferriol
- Plant Responses to Stress Programme, Centre for Research in Agricultural Genomics (CRAG-CSIC_UAB-UB) Cerdanyola del Vallès, Barcelona, Spain
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15
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Carbonell A, Lisón P, Daròs J. Multi-targeting of viral RNAs with synthetic trans-acting small interfering RNAs enhances plant antiviral resistance. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 100:720-737. [PMID: 31350772 PMCID: PMC6899541 DOI: 10.1111/tpj.14466] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/10/2019] [Accepted: 07/12/2019] [Indexed: 05/15/2023]
Abstract
RNA interference (RNAi)-based tools are used in multiple organisms to induce antiviral resistance through the sequence-specific degradation of target RNAs by complementary small RNAs. In plants, highly specific antiviral RNAi-based tools include artificial microRNAs (amiRNAs) and synthetic trans-acting small interfering RNAs (syn-tasiRNAs). syn-tasiRNAs have emerged as a promising antiviral tool allowing for the multi-targeting of viral RNAs through the simultaneous expression of several syn-tasiRNAs from a single precursor. Here, we compared in tomato plants the effects of an amiRNA construct expressing a single amiRNA and a syn-tasiRNA construct expressing four different syn-tasiRNAs against Tomato spotted wilt virus (TSWV), an economically important pathogen affecting tomato crops worldwide. Most of the syn-tasiRNA lines were resistant to TSWV, whereas the majority of the amiRNA lines were susceptible and accumulated viral progenies with mutations in the amiRNA target site. Only the two amiRNA lines with higher amiRNA accumulation were resistant, whereas resistance in syn-tasiRNA lines was not exclusive of lines with high syn-tasiRNA accumulation. Collectively, these results suggest that syn-tasiRNAs induce enhanced antiviral resistance because of the combined silencing effect of each individual syn-tasiRNA, which minimizes the possibility that the virus simultaneously mutates all different target sites to fully escape each syn-tasiRNA.
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Affiliation(s)
- Alberto Carbonell
- Instituto de Biología Molecular y Celular de PlantasConsejo Superior de Investigaciones Científicas‐Universitat Politècnica de València46022ValenciaSpain
| | - Purificación Lisón
- Instituto de Biología Molecular y Celular de PlantasConsejo Superior de Investigaciones Científicas‐Universitat Politècnica de València46022ValenciaSpain
| | - José‐Antonio Daròs
- Instituto de Biología Molecular y Celular de PlantasConsejo Superior de Investigaciones Científicas‐Universitat Politècnica de València46022ValenciaSpain
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16
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Liang C, Hao J, Li J, Baker B, Luo L. Artificial microRNA-mediated resistance to cucumber green mottle mosaic virus in Nicotiana benthamiana. PLANTA 2019; 250:1591-1601. [PMID: 31388829 DOI: 10.1007/s00425-019-03252-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 07/29/2019] [Indexed: 06/10/2023]
Abstract
MAIN CONCLUSION We describe a Nicotiana benthamiana system for rapid identification of artificial microRNA (amiRNA) to control cucumber green mottle mosaic virus (CGMMV) disease. Although artificial miRNA technology has been used to control other viral diseases, it has not been applied to reduce severe cucumber green mottle mosaic virus (CGMMV) disease and crop loss in the economically important cucurbits. We used our system to identify three amiRNAs targeting CGMMV RNA (amiR1-CP, amiR4-MP and amiR6-Rep) and show that their expression reduces CGMMV replication and disease in virus-infected plants. This work streamlines the process of generating amiRNA virus-resistant crops and can be broadly applied to identify active antiviral amiRNAs against a broad spectrum of viruses to control disease in diverse crops.
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Affiliation(s)
- Chaoqiong Liang
- College of Plant Protection/Beijing Key Laboratory of Seed Disease Testing and Control, China Agricultural University, Beijing, 100193, China
- College of Horticulture, China Agricultural University, Beijing, 100193, China
| | - Jianjun Hao
- School of Food and Agriculture, The University of Maine, Orono, ME, 04469, USA
| | - Jianqiang Li
- College of Plant Protection/Beijing Key Laboratory of Seed Disease Testing and Control, China Agricultural University, Beijing, 100193, China
| | - Barbara Baker
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, 94720, USA.
- United States Department of Agriculture, Plant Gene Expression Center, Agricultural Research Service, Albany, CA, 94710, USA.
| | - Laixin Luo
- College of Plant Protection/Beijing Key Laboratory of Seed Disease Testing and Control, China Agricultural University, Beijing, 100193, China.
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17
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Pixley KV, Falck-Zepeda JB, Giller KE, Glenna LL, Gould F, Mallory-Smith CA, Stelly DM, Stewart CN. Genome Editing, Gene Drives, and Synthetic Biology: Will They Contribute to Disease-Resistant Crops, and Who Will Benefit? ANNUAL REVIEW OF PHYTOPATHOLOGY 2019; 57:165-188. [PMID: 31150590 DOI: 10.1146/annurev-phyto-080417-045954] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Genetically engineered crops have been grown for more than 20 years, resulting in widespread albeit variable benefits for farmers and consumers. We review current, likely, and potential genetic engineering (GE) applications for the development of disease-resistant crop cultivars. Gene editing, gene drives, and synthetic biology offer novel opportunities to control viral, bacterial, and fungal pathogens, parasitic weeds, and insect vectors of plant pathogens. We conclude that there will be no shortage of GE applications totackle disease resistance and other farmer and consumer priorities for agricultural crops. Beyond reviewing scientific prospects for genetically engineered crops, we address the social institutional forces that are commonly overlooked by biological scientists. Intellectual property regimes, technology regulatory frameworks, the balance of funding between public- and private-sector research, and advocacy by concerned civil society groups interact to define who uses which GE technologies, on which crops, and for the benefit of whom. Ensuring equitable access to the benefits of genetically engineered crops requires affirmative policies, targeted investments, and excellent science.
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Affiliation(s)
- Kevin V Pixley
- International Maize and Wheat Improvement Center (CIMMYT), 56237 Texcoco, Mexico;
| | - Jose B Falck-Zepeda
- International Food Policy Research Institute (IFPRI), Washington, DC 20005-3915, USA
| | - Ken E Giller
- Plant Production Systems Group, Wageningen University & Research (WUR), 6700 AK Wageningen, The Netherlands
| | - Leland L Glenna
- Department of Agricultural Economics, Sociology, and Education, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Fred Gould
- Genetic Engineering and Society Center and Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Carol A Mallory-Smith
- Department of Crop and Soil Science, Oregon State University, Corvallis, Oregon 97331, USA
| | - David M Stelly
- Department of Soil and Crop Sciences, Texas A&M University, College Station, Texas 77843-2474, USA
| | - C Neal Stewart
- Department of Plant Sciences and Center for Agricultural Synthetic Biology, University of Tennessee, Knoxville, Tennessee 37996, USA
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18
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Carbonell A, López C, Daròs JA. Fast-Forward Identification of Highly Effective Artificial Small RNAs Against Different Tomato spotted wilt virus Isolates. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:142-156. [PMID: 30070616 DOI: 10.1094/mpmi-05-18-0117-ta] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Artificial small RNAs (sRNAs), including artificial microRNAs (amiRNAs) and synthetic trans-acting small interfering RNAs (syn-tasiRNAs), are used to silence viral RNAs and confer antiviral resistance in plants. Here, the combined use of recent high-throughput methods for generating artificial sRNA constructs and the Tomato spotted wilt virus (TSWV)-Nicotiana benthamiana pathosystem allowed for the simple and rapid identification of amiRNAs with high anti-TSWV activity. A comparative analysis between the most effective amiRNA construct and a syn-tasiRNA construct including the four most effective amiRNA sequences showed that both were highly effective against two different TSWV isolates. These results highlight the usefulness of this high-throughput methodology for the fast-forward identification of artificial sRNAs with high antiviral activity prior to time-consuming generation of stably transformed plants.
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Affiliation(s)
- Alberto Carbonell
- 1 Instituto de Biología Molecular y Celular de Plantas (Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València), 46022 Valencia, Spain; and
| | - Carmelo López
- 2 Instituto de Conservación y Mejora de la Agrodiversidad Valenciana, Universitat Politècnica de València, 46022 Valencia, Spain
| | - José-Antonio Daròs
- 1 Instituto de Biología Molecular y Celular de Plantas (Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València), 46022 Valencia, Spain; and
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Design, Synthesis, and Functional Analysis of Highly Specific Artificial Small RNAs with Antiviral Activity in Plants. Methods Mol Biol 2019; 2028:231-246. [PMID: 31228118 DOI: 10.1007/978-1-4939-9635-3_13] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Artificial microRNAs (amiRNAs) and synthetic trans-acting small interfering RNAs (syn-tasiRNAs) are two classes of artificial small RNAs (sRNAs) that have been broadly used to confer antiviral resistance in plants. However, methods for designing, synthesizing and functionally analyzing antiviral artificial sRNAs have not been optimized for time and cost-effectiveness and high-throughput applicability since recently. Here we present a systematic methodology for the simple and fast-forward design, generation, and functional analysis of large numbers of artificial sRNA constructs engineered to induce high levels of antiviral resistance in plants. Artificial sRNA constructs are transiently expressed in Nicotiana benthamiana plants, which are subsequently inoculated with the virus of interest. The antiviral activity of each artificial sRNA construct is assessed by monitoring viral symptom appearance, and through molecular analysis of virus accumulation in plant tissues. This approach is aimed to easily identify artificial sRNAs with high antiviral activity that could be expressed in transgenic plants for highly durable antiviral resistance.
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20
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Jacobson AL, Duffy S, Sseruwagi P. Whitefly-transmitted viruses threatening cassava production in Africa. Curr Opin Virol 2018; 33:167-176. [PMID: 30243102 DOI: 10.1016/j.coviro.2018.08.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 08/28/2018] [Accepted: 08/31/2018] [Indexed: 10/28/2022]
Abstract
Emerging plant viruses are one of the greatest problems facing crop production worldwide, and have severe consequences in the developing world where subsistence farming is a major source of food production, and knowledge and resources for management are limited. In Africa, evolution of two viral disease complexes, cassava mosaic begomoviruses (CMBs) (Geminiviridae) and cassava brown streak viruses (CBSVs) (Potyviridae), have resulted in severe pandemics that continue to spread and threaten cassava production. Identification of genetically diverse and rapidly evolving CMBs and CBSVs, extensive genetic variation in the vector, Bemisia tabaci (Hemiptera: Aleyrodidae), and numerous secondary endosymbiont profiles that influence vector phenotypes suggest that complex local and regional vector-virus-plant-environment interactions may be driving the evolution and epidemiology of these viruses.
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Affiliation(s)
- Alana Lynn Jacobson
- Department of Entomology and Plant Pathology, Auburn University, 301 Funchess Hall, Auburn, AL 36849, USA.
| | - Siobain Duffy
- Department of Ecology, Evolution, and Natural Resources, Rutgers University, 14 College Farm Rd, New Brunswick, NJ 08901, USA
| | - Peter Sseruwagi
- Mikocheni Agricultural Research Institute, P.O. Box 6226, Dar es Salaam, Tanzania
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21
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Abstract
The high mutation rate of RNA viruses is credited with their evolvability and virulence. This Primer, however, discusses recent evidence that this is, in part, a byproduct of selection for faster genomic replication.
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Affiliation(s)
- Siobain Duffy
- School of Environmental and Biological Sciences, Rutgers, the State University of New Jersey, New Brunswick, New Jersey, United States of America
- * E-mail:
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22
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23
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Carbonell A, Daròs J. Artificial microRNAs and synthetic trans-acting small interfering RNAs interfere with viroid infection. MOLECULAR PLANT PATHOLOGY 2017; 18:746-753. [PMID: 28026103 PMCID: PMC6638287 DOI: 10.1111/mpp.12529] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 12/14/2016] [Accepted: 12/17/2016] [Indexed: 05/18/2023]
Abstract
Artificial microRNAs (amiRNAs) and synthetic trans-acting small interfering RNAs (syn-tasiRNAs) are two classes of artificial small RNAs (sRNAs) engineered to silence endogenous transcripts as well as viral RNAs in plants. Here, we explore the possibility of using amiRNAs and syn-tasiRNAs to specifically interfere with infections by viroids, small (250-400-nucleotide) non-coding circular RNAs with compact secondary structure infecting a wide range of plant species. The combined use of recent high-throughput methods for artificial sRNA construct generation and the Potato spindle tuber viroid (PSTVd)-Nicotiana benthamiana pathosystem allowed for the simple and time-effective screening of multiple artificial sRNAs targeting sites distributed along PSTVd RNAs of (+) or (-) polarity. The majority of amiRNAs were highly active in agroinfiltrated leaves when co-expressed with an infectious PSTVd transcript, as were syn-tasiRNAs derived from a construct including the five most effective amiRNA sequences. A comparative analysis showed that the effects of the most effective amiRNA and of the syn-tasiRNAs were similar in agroinfiltrated leaves, as well as in upper non-agroinfiltrated leaves in which PSTVd accumulation was significantly delayed. These results suggest that amiRNAs and syn-tasiRNAs can be used effectively to control viroid infections in plants.
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Affiliation(s)
- Alberto Carbonell
- Instituto de Biología Molecular y Celular de Plantas (Consejo Superior de Investigaciones Científicas‐Universidad Politécnica de Valencia)Valencia46022Spain
| | - José‐Antonio Daròs
- Instituto de Biología Molecular y Celular de Plantas (Consejo Superior de Investigaciones Científicas‐Universidad Politécnica de Valencia)Valencia46022Spain
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24
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Catalán P, Arias CF, Cuesta JA, Manrubia S. Adaptive multiscapes: an up-to-date metaphor to visualize molecular adaptation. Biol Direct 2017; 12:7. [PMID: 28245845 PMCID: PMC5331743 DOI: 10.1186/s13062-017-0178-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 02/11/2017] [Indexed: 01/08/2023] Open
Abstract
Background Wright’s metaphor of the fitness landscape has shaped and conditioned our view of the adaptation of populations for almost a century. Since its inception, and including criticism raised by Wright himself, the concept has been surrounded by controversy. Among others, the debate stems from the intrinsic difficulty to capture important features of the space of genotypes, such as its high dimensionality or the existence of abundant ridges, in a visually appealing two-dimensional picture. Two additional currently widespread observations come to further constrain the applicability of the original metaphor: the very skewed distribution of phenotype sizes (which may actively prevent, due to entropic effects, the achievement of fitness maxima), and functional promiscuity (i.e. the existence of secondary functions which entail partial adaptation to environments never encountered before by the population). Results Here we revise some of the shortcomings of the fitness landscape metaphor and propose a new “scape” formed by interconnected layers, each layer containing the phenotypes viable in a given environment. Different phenotypes within a layer are accessible through mutations with selective value, while neutral mutations cause displacements of populations within a phenotype. A different environment is represented as a separated layer, where phenotypes may have new fitness values, other phenotypes may be viable, and the same genotype may yield a different phenotype, representing genotypic promiscuity. This scenario explicitly includes the many-to-many structure of the genotype-to-phenotype map. A number of empirical observations regarding the adaptation of populations in the light of adaptive multiscapes are reviewed. Conclusions Several shortcomings of Wright’s visualization of fitness landscapes can be overcome through adaptive multiscapes. Relevant aspects of population adaptation, such as neutral drift, functional promiscuity or environment-dependent fitness, as well as entropic trapping and the concomitant impossibility to reach fitness peaks are visualized at once. Adaptive multiscapes should aid in the qualitative understanding of the multiple pathways involved in evolutionary dynamics. Reviewers This article was reviewed by Eugene Koonin and Ricard Solé.
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Affiliation(s)
- Pablo Catalán
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Madrid, Spain.,Departamento de Matemáticas, Universidad Carlos III de Madrid, Madrid, Spain
| | - Clemente F Arias
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Madrid, Spain
| | - Jose A Cuesta
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Madrid, Spain.,Departamento de Matemáticas, Universidad Carlos III de Madrid, Madrid, Spain.,Institute for Biocomputation and Physics of Complex Systems, Zaragoza, Spain.,UC3M-BS Institute of Financial Big Data (IFiBiD), Madrid, Spain
| | - Susanna Manrubia
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Madrid, Spain. .,National Biotechnology Centre (CSIC), c/ Darwin 3, Madrid, 28049, Spain.
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25
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Carbonell A, Carrington JC, Daròs JA. Fast-forward generation of effective artificial small RNAs for enhanced antiviral defense in plants. RNA & DISEASE 2016; 3:e1130. [PMID: 26925463 PMCID: PMC4768481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023] Open
Abstract
Artificial small RNAs (sRNAs) are short ≈21-nt non-coding RNAs engineered to inactivate sequence complementary RNAs. In plants, they have been extensively used to silence cellular transcripts in gene function analyses and to target invading RNA viruses to induce resistance. Current artificial sRNA-based antiviral resistance in plants is mainly limited to a single virus, and is jeopardized by the emergence of mutations in the artificial sRNA target site or by the presence of co-infecting viruses. Hence, there is a need to further develop the artificial sRNA approach to generate more broad and durable antiviral resistance in plants. A recently developed toolbox allows for the time and cost-effective large-scale production of artificial sRNA constructs in plants. The toolbox includes the P-SAMS web tool for the automated design of artificial sRNAs, and a new generation of artificial microRNA and synthetic trans-acting small interfering RNA (syn-tasiRNA) vectors for direct cloning and high expression of artificial sRNAs. Here we describe how the simplicity and high-throughput capability of these new technologies should accelerate the study of artificial sRNA-based antiviral resistance in plants. In particular, we discuss the potential of the syn-tasiRNA approach as a promising strategy for developing more effective, durable and broad antiviral resistance in plants.
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Affiliation(s)
- Alberto Carbonell
- Instituto de Biología Molecular y Celular de Plantas (Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia), Valencia, 46022 Spain
| | | | - José-Antonio Daròs
- Instituto de Biología Molecular y Celular de Plantas (Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia), Valencia, 46022 Spain
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26
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Domingo E. Molecular Basis of Genetic Variation of Viruses. VIRUS AS POPULATIONS 2016. [PMCID: PMC7149591 DOI: 10.1016/b978-0-12-800837-9.00002-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Genetic variation is a necessity of all biological systems. Viruses use all known mechanisms of variation: mutation, several forms of recombination, and segment reassortment in the case of viruses with a segmented genome. These processes are intimately connected with the replicative machineries of viruses, as well as with fundamental physico-chemical properties of nucleotides when acting as template or substrate residues. Recombination has been viewed as a means to rescue viable genomes from unfit parents, or to produce large modifications for the exploration of phenotypic novelty. All types of genetic variation can act conjointly as blind processes to provide the raw materials for adaptation to the changing environments in which viruses must replicate.
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27
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Multiple virus resistance using artificial trans-acting siRNAs. J Virol Methods 2015; 228:16-20. [PMID: 26562057 DOI: 10.1016/j.jviromet.2015.11.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 11/05/2015] [Accepted: 11/06/2015] [Indexed: 11/24/2022]
Abstract
Plant TAS gene encoded trans-acting siRNAs (ta-siRNAs) regulate the expression of target mRNAs by guiding their cleavage at the sequence complementary region as microRNAs. Since one TAS transcript is cleaved into multiple ta-siRNAs in a phased manner, TAS genes may be engineered to express multiple artificial ta-siRNAs (ata-siRNAs) that target multiple viruses at several distinct genomic positions. To test this hypothesis, the Arabidopsis TAS3a gene was engineered to express ata-siRNAs targeting the genome of Turnip mosaic virus (TuMV) and Cucumber mosaic virus (CMV). Transgenic Arabidopsis thaliana plants expressing these ata-siRNAs showed high level of resistance to both viruses. These results suggest that plant TAS genes can be modified to express artificial ta-siRNAs to confer multiple virus resistance and could have broad applications for future development in virus resistance strategies.
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28
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Abstract
Transgenic resistance to plant viruses is an important technology for control of plant virus infection, which has been demonstrated for many model systems, as well as for the most important plant viruses, in terms of the costs of crop losses to disease, and also for many other plant viruses infecting various fruits and vegetables. Different approaches have been used over the last 28 years to confer resistance, to ascertain whether particular genes or RNAs are more efficient at generating resistance, and to take advantage of advances in the biology of RNA interference to generate more efficient and environmentally safer, novel "resistance genes." The approaches used have been based on expression of various viral proteins (mostly capsid protein but also replicase proteins, movement proteins, and to a much lesser extent, other viral proteins), RNAs [sense RNAs (translatable or not), antisense RNAs, satellite RNAs, defective-interfering RNAs, hairpin RNAs, and artificial microRNAs], nonviral genes (nucleases, antiviral inhibitors, and plantibodies), and host-derived resistance genes (dominant resistance genes and recessive resistance genes), and various factors involved in host defense responses. This review examines the above range of approaches used, the viruses that were tested, and the host species that have been examined for resistance, in many cases describing differences in results that were obtained for various systems developed in the last 20 years. We hope this compilation of experiences will aid those who are seeking to use this technology to provide resistance in yet other crops, where nature has not provided such.
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Affiliation(s)
| | - Peter Palukaitis
- Department of Horticultural Sciences, Seoul Women's University, Seoul, Republic of Korea.
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29
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Ilardi V, Tavazza M. Biotechnological strategies and tools for Plum pox virus resistance: trans-, intra-, cis-genesis, and beyond. FRONTIERS IN PLANT SCIENCE 2015; 6:379. [PMID: 26106397 PMCID: PMC4458569 DOI: 10.3389/fpls.2015.00379] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 05/12/2015] [Indexed: 05/19/2023]
Abstract
Plum pox virus (PPV) is the etiological agent of sharka, the most devastating and economically important viral disease affecting Prunus species. It is widespread in most stone fruits producing countries even though eradication and quarantine programs are in place. The development of resistant cultivars and rootstocks remains the most ecologically and economically suitable approach to achieve long-term control of sharka disease. However, the few PPV resistance genetic resources found in Prunus germplasm along with some intrinsic biological features of stone fruit trees pose limits for efficient and fast breeding programs. This review focuses on an array of biotechnological strategies and tools, which have been used, or may be exploited to confer PPV resistance. A considerable number of scientific studies clearly indicate that robust and predictable resistance can be achieved by transforming plant species with constructs encoding intron-spliced hairpin RNAs homologous to conserved regions of the PPV genome. In addition, we discuss how recent advances in our understanding of PPV biology can be profitably exploited to develop viral interference strategies. In particular, genetic manipulation of host genes by which PPV accomplishes its infection cycle already permits the creation of intragenic resistant plants. Finally, we review the emerging genome editing technologies based on ZFN, TALEN and CRISPR/Cas9 engineered nucleases and how the knockout of host susceptibility genes will open up next generation of PPV resistant plants.
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Affiliation(s)
- Vincenza Ilardi
- Centro di Ricerca per la Patologia Vegetale, Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria, Rome, Italy
| | - Mario Tavazza
- UTAGRI Centro Ricerche Casaccia, Agenzia Nazionale per le Nuove Tecnologie, l’Energia e lo Sviluppo Economico Sostenibile, Rome, Italy
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30
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Zhang H, Tang X, Zhu C, Song Y, Yin J, Xu J, Ertl HCJ, Zhou D. Adenovirus-mediated artificial MicroRNAs targeting matrix or nucleoprotein genes protect mice against lethal influenza virus challenge. Gene Ther 2015; 22:653-62. [PMID: 25835311 DOI: 10.1038/gt.2015.31] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 02/17/2015] [Accepted: 03/24/2015] [Indexed: 02/06/2023]
Abstract
Influenza virus (IV) infection is a major public health problem, causing millions of cases of severe illness and as many as 500 000 deaths each year worldwide. Given the limitations of current prevention or treatment of acute influenza, novel therapies are needed. RNA interference (RNAi) through microRNAs (miRNA) is an emerging technology that can suppress virus replication in vitro and in vivo. Here, we describe a novel strategy for the treatment of infuenza based on RNAi delivered by a replication-defective adenovirus (Ad) vector, derived from chimpanzee serotype 68 (AdC68). Our results showed that artificial miRNAs (amiRNAs) specifically targeting conserved regions of the IV genome could effectively inhibit virus replication in human embryonic kidney 293 cells. Moreover, our results demonstrated that prophylactic treatment with AdC68 expressing amiRNAs directed against M1, M2 or nucleoprotein genes of IV completely protected mice from homologous A/PR8 virus challenge and partially protected the mice from heterologous influenza A virus strains such as H9N2 and H5N1. Collectively, our data demonstrate that amiRNAs targeting the conserved regions of influenza A virus delivered by Ad vectors should be pursued as a novel strategy for prophylaxis of IV infection in humans and animals.
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Affiliation(s)
- H Zhang
- Vaccine Research Center, Key Laboratory of Molecular Virology & Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - X Tang
- Vaccine Research Center, Key Laboratory of Molecular Virology & Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - C Zhu
- Vaccine Research Center, Key Laboratory of Molecular Virology & Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Y Song
- Vaccine Research Center, Key Laboratory of Molecular Virology & Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - J Yin
- Vaccine Research Center, Key Laboratory of Molecular Virology & Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - J Xu
- Shanghai Public Health Clinical Center, the Institutes of Biomedical Sciences, Key Laboratory of Medical Molecular Virology of Shanghai Medical College and Institute of Medical Microbiology, Fudan University, Shanghai, China
| | - H C J Ertl
- The Wistar Institute, Philadelphia, PA, USA
| | - D Zhou
- Vaccine Research Center, Key Laboratory of Molecular Virology & Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
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Whitfield AE, Rotenberg D. Disruption of insect transmission of plant viruses. CURRENT OPINION IN INSECT SCIENCE 2015; 8:79-87. [PMID: 32846687 DOI: 10.1016/j.cois.2015.01.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 01/13/2015] [Accepted: 01/14/2015] [Indexed: 06/11/2023]
Abstract
Plant-infecting viruses are transmitted by a diverse array of organisms including insects, mites, nematodes, fungi, and plasmodiophorids. Virus interactions with these vectors are diverse, but there are some commonalities. Generally the infection cycle begins with the vector encountering the virus in the plant and the virus is acquired by the vector. The virus must then persist in or on the vector long enough for the virus to be transported to a new host and delivered into the plant cell. Plant viruses rely on their vectors for breaching the plant cell wall to be delivered directly into the cytosol. In most cases, viral capsid or membrane glycoproteins are the specific viral proteins that are required for transmission and determinants of vector specificity. Specific molecules in vectors also interact with the virus and while there are few-identified to no-identified receptors, candidate recognition molecules are being further explored in these systems. Due to the specificity of virus transmission by vectors, there are defined steps that represent good targets for interdiction strategies to disrupt the disease cycle. This review focuses on new technologies that aim to disrupt the virus-vector interaction and focuses on a few of the well-characterized virus-vector interactions in the field. In closing, we discuss the importance of integration of these technologies with current methods for plant virus disease control.
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Affiliation(s)
- Anna E Whitfield
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66502, USA.
| | - Dorith Rotenberg
- Department of Plant Pathology, Kansas State University, Manhattan, KS 66502, USA
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Bedhomme S, Hillung J, Elena SF. Emerging viruses: why they are not jacks of all trades? Curr Opin Virol 2014; 10:1-6. [PMID: 25467278 DOI: 10.1016/j.coviro.2014.10.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 10/27/2014] [Accepted: 10/28/2014] [Indexed: 12/21/2022]
Abstract
In order to limit the impact of the recent pandemics ignited by viral host jumps, it is necessary to better understand the ecological and evolutionary factors influencing the early steps of emergence and the interactions between them. Antagonistic pleiotropy, that is, the negative fitness effect in the primary host of mutations allowing the infection of and the multiplication in a new host, has long been thought to be the main limitation to the evolution of generalist viruses and thus to emergence. However, the accumulation of experimental examples contradicting the hypothesis of antagonistic pleiotropy has highlighted the importance of other factors such as the epistasis between mutations increasing the adaptation to a new host. Epistasis is pervasive in viruses, affects the shape of the adaptive landscape and consequently the accessibility of evolutionary pathways. Finally, recent studies have gone steps further in the complexity of viral fitness determinism and stressed the potential importance of the epistatic pleiotropy and of the impact of host living conditions.
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Affiliation(s)
- Stéphanie Bedhomme
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, 46022 Valencia, Spain.
| | - Julia Hillung
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, 46022 Valencia, Spain
| | - Santiago F Elena
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, 46022 Valencia, Spain; The Santa Fe Institute, Santa Fe, NM 87501, USA
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Du J, Guo X, Gao S, Luo J, Gong X, Hao C, Yang B, Lin T, Shao J, Cong G, Chang H. Induction of protection against foot-and-mouth disease virus in cell culture and transgenic suckling mice by miRNA targeting integrin αv receptor. J Biotechnol 2014; 187:154-61. [DOI: 10.1016/j.jbiotec.2014.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 06/25/2014] [Accepted: 07/01/2014] [Indexed: 11/29/2022]
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Abstract
Viruses are common agents of plant infectious diseases. During last decades, worldwide agriculture production has been compromised by a series of epidemics caused by new viruses that spilled over from reservoir species or by new variants of classic viruses that show new pathogenic and epidemiological properties. Virus emergence has been generally associated with ecological change or with intensive agronomical practices. However, the complete picture is much more complex since the viral populations constantly evolve and adapt to their new hosts and vectors. This chapter puts emergence of plant viruses into the framework of evolutionary ecology, genetics, and epidemiology. We will stress that viral emergence begins with the stochastic transmission of preexisting genetic variants from the reservoir to the new host, whose fate depends on their fitness on each hosts, followed by adaptation to new hosts or vectors, and finalizes with an efficient epidemiological spread.
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Affiliation(s)
- Santiago F Elena
- Instituto de Biología Molecular y Celular de Plantas, CSIC-UPV, Campus UPV, València, Spain; The Santa Fe Institute, Santa Fe, New Mexico, USA
| | - Aurora Fraile
- Centro de Biotecnología y Genómica de Plantas, UPM-INIA, and ETSI Agrónomos, UPM, Campus de Montegancedo, Madrid, Spain
| | - Fernando García-Arenal
- Centro de Biotecnología y Genómica de Plantas, UPM-INIA, and ETSI Agrónomos, UPM, Campus de Montegancedo, Madrid, Spain.
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Hillung J, Cuevas JM, Valverde S, Elena SF. Experimental evolution of an emerging plant virus in host genotypes that differ in their susceptibility to infection. Evolution 2014; 68:2467-80. [PMID: 24889935 DOI: 10.1111/evo.12458] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 05/16/2014] [Indexed: 01/02/2023]
Abstract
This study evaluates the extent to which genetic differences among host individuals from the same species condition the evolution of a plant RNA virus. We performed a threefold replicated evolution experiment in which Tobacco etch potyvirus isolate At17b (TEV-At17b), adapted to Arabidopsis thaliana ecotype Ler-0, was serially passaged in five genetically heterogeneous ecotypes of A. thaliana. After 15 passages we found that evolved viruses improved their fitness, showed higher infectivity and stronger virulence in their local host ecotypes. The genome of evolved lineages was sequenced and putative adaptive mutations identified. Host-driven convergent mutations have been identified. Evidences supported selection for increased translational efficiency. Next, we sought for the specificity of virus adaptation by infecting all five ecotypes with all 15 evolved virus populations. We found that some ecotypes were more permissive to infection than others, and that some evolved virus isolates were more specialist/generalist than others. The bipartite network linking ecotypes with evolved viruses was significantly nested but not modular, suggesting that hard-to-infect ecotypes were infected by generalist viruses whereas easy-to-infect ecotypes were infected by all viruses, as predicted by a gene-for-gene model of infection.
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Affiliation(s)
- Julia Hillung
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Campus UPV CPI 8E, C/Ingeniero Fausto Elio s/n, 46022, València, Spain
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Ramesh SV, Ratnaparkhe MB, Kumawat G, Gupta GK, Husain SM. Plant miRNAome and antiviral resistance: a retrospective view and prospective challenges. Virus Genes 2014; 48:1-14. [PMID: 24445902 DOI: 10.1007/s11262-014-1038-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 01/12/2014] [Indexed: 12/20/2022]
Abstract
MicroRNAs (miRNAs) are small regulatory RNAs that play a defining role in post-transcriptional gene silencing of eukaryotes by either mRNA cleavage or translational inhibition. Plant miRNAs have been implicated in innumerable growth and developmental processes that extend beyond their ability to respond to biotic and abiotic stresses. Active in an organism's immune defence response, host miRNAs display a propensity to target viral genomes. During viral invasion, these virus-targeting miRNAs can be identified by their altered expression. All the while, pathogenic viruses, as a result of their long-term interaction with plants, have been evolving viral suppressors of RNA silencing (VSRs), as well as viral-encoded miRNAs as a counter-defence strategy. However, the gene silencing attribute of miRNAs has been ingeniously manipulated to down-regulate the expression of any gene of interest, including VSRs, in artificial miRNA (amiRNA)-based transgenics. Since we currently have a better understanding of the intricacies of miRNA-mediated gene regulation in plant-virus interactions, the majority of miRNAs manipulated to confer antiviral resistance to date are in plants. This review will share the insights gained from the studies of plant-virus combat and from the endeavour to manipulate miRNAs, including prospective challenges in the context of the evolutionary dynamics of the viral genome. Next generation sequencing technologies and bioinformatics analysis will further delineate the molecular details of host-virus interactions. The need for appropriate environmental risk assessment principles specific to amiRNA-based virus resistance is also discussed.
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Affiliation(s)
- Shunmugiah Veluchamy Ramesh
- Directorate of Soybean Research, Indian Council of Agricultural Research (ICAR), Khandwa Road, Indore, 452001, Madhya Pradesh, India,
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Martínez F, Elena SF, Daròs JA. Fate of artificial microRNA-mediated resistance to plant viruses in mixed infections. PHYTOPATHOLOGY 2013; 103:870-6. [PMID: 23617337 DOI: 10.1094/phyto-09-12-0233-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Artificial microRNAs (amiRNAs) are the expression products of engineered microRNA (miRNA) genes that efficiently and specifically downregulate RNAs that contain complementary sequences. Transgenic plants expressing high levels of one or more amiRNAs targeting particular sequences in the genomes of some RNA viruses have shown specific resistance to the corresponding virus. This is the case of the Arabidopsis thaliana transgenic line 12-4 expressing a high level of the amiR159-HC-Pro targeting 21 nucleotides in the Turnip mosaic virus (TuMV) (family Potyviridae) cistron coding for the viral RNA-silencing suppressor HC-Pro that is highly resistant to TuMV infection. In this study, we explored the fate of this resistance when the A. thaliana 12-4 plants are challenged with a second virus in addition to TuMV. The A. thaliana 12-4 plants maintained the resistance to TuMV when this virus was co-inoculated with Tobacco mosaic virus, Tobacco rattle virus (TRV), Cucumber mosaic virus (CMV), Turnip yellow mosaic virus, Cauliflower mosaic virus (CaMV), Lettuce mosaic virus, or Plum pox virus. However, when the plants were preinfected with these viruses, TuMV was able to co-infect 12-4 plants preinfected with TRV, CaMV, and, particularly, CMV. Therefore, preinfection by another virus jeopardizes the amiRNA-mediated resistance to TuMV.
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Affiliation(s)
- Fernando Martínez
- Instituto de Biologia Molecular y Celular de Plantas, Valencia, Spain
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39
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Lafforgue G, Martínez F, Niu QW, Chua NH, Daròs JA, Elena SF. Improving the effectiveness of artificial microRNA (amiR)-mediated resistance against Turnip mosaic virus by combining two amiRs or by targeting highly conserved viral genomic regions. J Virol 2013; 87:8254-6. [PMID: 23698292 PMCID: PMC3700214 DOI: 10.1128/jvi.00914-13] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 05/10/2013] [Indexed: 01/04/2023] Open
Abstract
A drawback of recent antiviral therapies based on the transgenic expression of artificial microRNAs (amiRs) is the ease with which viruses generate escape mutations. Here, we show two alternative strategies for improving the effectiveness of resistance in plants. First, we expressed two amiRs complementary to independent targets in the viral genome, and second, we designed amiRs complementary to highly conserved RNA motifs in the viral genome.
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Affiliation(s)
- Guillaume Lafforgue
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, València, Spain
| | - Fernando Martínez
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, València, Spain
| | - Qi-Wen Niu
- Laboratory of Plant Biology, Rockefeller University, New York, New York, USA
| | - Nam-Hai Chua
- Laboratory of Plant Biology, Rockefeller University, New York, New York, USA
| | - José-Antonio Daròs
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, València, Spain
| | - Santiago F. Elena
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, València, Spain
- The Santa Fe Institute, Santa Fe, New Mexico, USA
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40
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Heinemann JA, Agapito-Tenfen SZ, Carman JA. A comparative evaluation of the regulation of GM crops or products containing dsRNA and suggested improvements to risk assessments. ENVIRONMENT INTERNATIONAL 2013; 55:43-55. [PMID: 23523853 DOI: 10.1016/j.envint.2013.02.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 02/08/2013] [Accepted: 02/22/2013] [Indexed: 05/20/2023]
Abstract
Changing the nature, kind and quantity of particular regulatory-RNA molecules through genetic engineering can create biosafety risks. While some genetically modified organisms (GMOs) are intended to produce new regulatory-RNA molecules, these may also arise in other GMOs not intended to express them. To characterise, assess and then mitigate the potential adverse effects arising from changes to RNA requires changing current approaches to food or environmental risk assessments of GMOs. We document risk assessment advice offered to government regulators in Australia, New Zealand and Brazil during official risk evaluations of GM plants for use as human food or for release into the environment (whether for field trials or commercial release), how the regulator considered those risks, and what that experience teaches us about the GMO risk assessment framework. We also suggest improvements to the process.
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Affiliation(s)
- Jack A Heinemann
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.
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41
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Fahim M, Larkin PJ. Designing effective amiRNA and multimeric amiRNA against plant viruses. Methods Mol Biol 2013; 942:357-77. [PMID: 23027061 DOI: 10.1007/978-1-62703-119-6_19] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
RNA-mediated virus resistance is increasingly becoming a method of choice for antiviral defense in plants when effective natural resistance is unavailable. In this chapter we discuss the design principles of artificial micro RNA (amiRNA), in which a natural miRNA precursor gene is modified to target a different species of RNA, in particular viral RNA. In addition, we explore the advantages and effectiveness of multiple amiRNAs within one polycistronic amiRNA precursor against a virus, as illustrated with Wheat streak mosaic virus, WSMV. The judicious selection of amiRNAs, which are sequences of short length as compared to other related methodologies of RNA interference, greatly assists in avoiding unintended off-targets in the host plant. The viral sequences targeted can be genomic or replicative and should be derived from conserved regions of the published WSMV genome. In short, using published folding and miRNA selection rules and algorithms, candidate miRNA sequences are selected from conserved regions between a number of WSMV genomes, and are BLASTed against wheat TIGR ESTs. Five miRNAs are selected that are least likely to interfere with the expression of transcripts from the wheat host. Then, the natural miRNA in each of the five arms of the polycistronic rice miR395 is replaced in silico with the chosen artificial miRNAs. This artificial precursor is transformed into wheat behind a ubiquitin promoter, and its integration into transformed wheat plants is confirmed by PCR and Southern blot analysis. We have demonstrated the effectiveness of this methodology using an amiRNA precursor that we have termed Fanguard. The processing of amiRNAs in transgenic leaves is verified through splinted ligation assay, and the functionality of the transgene in preventing viral replication is verified by virus bioassay. Resistance is confirmed using mechanical virus inoculation over two subsequent generations. This example demonstrates the potential of polycistronic amiRNA to achieve stable immunity to economically important viruses.
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Affiliation(s)
- Muhammad Fahim
- Lab of Plant Developmental Molecular Genetics, School of Life Science and Biotechnology, Korea University, Seoul, South Korea
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Monjane AL, Pande D, Lakay F, Shepherd DN, van der Walt E, Lefeuvre P, Lett JM, Varsani A, Rybicki EP, Martin DP. Adaptive evolution by recombination is not associated with increased mutation rates in Maize streak virus. BMC Evol Biol 2012; 12:252. [PMID: 23268599 PMCID: PMC3556111 DOI: 10.1186/1471-2148-12-252] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Accepted: 12/12/2012] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Single-stranded (ss) DNA viruses in the family Geminiviridae are proving to be very useful in real-time evolution studies. The high mutation rate of geminiviruses and other ssDNA viruses is somewhat mysterious in that their DNA genomes are replicated in host nuclei by high fidelity host polymerases. Although strand specific mutation biases observed in virus species from the geminivirus genus Mastrevirus indicate that the high mutation rates in viruses in this genus may be due to mutational processes that operate specifically on ssDNA, it is currently unknown whether viruses from other genera display similar strand specific mutation biases. Also, geminivirus genomes frequently recombine with one another and an alternative cause of their high mutation rates could be that the recombination process is either directly mutagenic or produces a selective environment in which the survival of mutants is favoured. To investigate whether there is an association between recombination and increased basal mutation rates or increased degrees of selection favoring the survival of mutations, we compared the mutation dynamics of the MSV-MatA and MSV-VW field isolates of Maize streak virus (MSV; Mastrevirus), with both a laboratory constructed MSV recombinant, and MSV recombinants closely resembling MSV-MatA. To determine whether strand specific mutation biases are a general characteristic of geminivirus evolution we compared mutation spectra arising during these MSV experiments with those arising during similar experiments involving the geminivirus Tomato yellow leaf curl virus (Begomovirus genus). RESULTS Although both the genomic distribution of mutations and the occurrence of various convergent mutations at specific genomic sites indicated that either mutation hotspots or selection for adaptive mutations might elevate observed mutation rates in MSV, we found no association between recombination and mutation rates. Importantly, when comparing the mutation spectra of MSV and TYLCV we observed similar strand specific mutation biases arising predominantly from imbalances in the complementary mutations G → T: C → A. CONCLUSIONS While our results suggest that recombination does not strongly influence mutation rates in MSV, they indicate that high geminivirus mutation rates are at least partially attributable to increased susceptibility of all geminivirus genomes to oxidative damage while in a single stranded state.
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Affiliation(s)
- Adérito L Monjane
- Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, Cape Town 7701, South Africa
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43
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Martínez F, Lafforgue G, Morelli MJ, González-Candelas F, Chua NH, Daròs JA, Elena SF. Ultradeep sequencing analysis of population dynamics of virus escape mutants in RNAi-mediated resistant plants. Mol Biol Evol 2012; 29:3297-307. [PMID: 22593223 PMCID: PMC7187544 DOI: 10.1093/molbev/mss135] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Plant artificial micro-RNAs (amiRs) have been engineered to target viral genomes and induce their degradation. However, the exceptional evolutionary plasticity of RNA viruses threatens the durability of the resistance conferred by these amiRs. It has recently been shown that viral populations not experiencing strong selective pressure from an antiviral amiR may already contain enough genetic variability in the target sequence to escape plant resistance in an almost deterministic manner. Furthermore, it has also been shown that viral populations exposed to subinhibitory concentrations of the antiviral amiR speed up this process. In this article, we have characterized the molecular evolutionary dynamics of an amiR target sequence in a viral genome under both conditions. The use of Illumina ultradeep sequencing has allowed us to identify virus sequence variants at frequencies as low as 2 × 10(-6) and to track their variation in time before and after the viral population was able of successfully infecting plants fully resistant to the ancestral virus. We found that every site in the amiR-target sequence of the viral genome presented variation and that the variant that eventually broke resistance was sampled among the many coexisting ones. In this system, viral evolution in fully susceptible plants results from an equilibrium between mutation and genetic drift, whereas evolution in partially resistant plants originates from more complex dynamics involving mutation, selection, and drift.
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Affiliation(s)
- Fernando Martínez
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, Valencia, Spain
| | - Guillaume Lafforgue
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, Valencia, Spain
| | - Marco J. Morelli
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Fernando González-Candelas
- Unidad Mixta Genómica y Salud, Centro Superior de Investigación en Salud Pública-Instituto Cavanilles de Biodiversitat i Biologia Evolutiva, Universitat de València, València, Spain
| | - Nam-Hai Chua
- Laboratory of Plant Biology, Rockefeller University
| | - José-Antonio Daròs
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, Valencia, Spain
| | - Santiago F. Elena
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, Valencia, Spain
- The Santa Fe Institute, Santa Fe, New Mexico
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Kinoshita N, Wang H, Kasahara H, Liu J, Macpherson C, Machida Y, Kamiya Y, Hannah MA, Chua NH. IAA-Ala Resistant3, an evolutionarily conserved target of miR167, mediates Arabidopsis root architecture changes during high osmotic stress. THE PLANT CELL 2012; 24:3590-602. [PMID: 22960911 PMCID: PMC3480289 DOI: 10.1105/tpc.112.097006] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The functions of microRNAs and their target mRNAs in Arabidopsis thaliana development have been widely documented; however, roles of stress-responsive microRNAs and their targets are not as well understood. Using small RNA deep sequencing and ATH1 microarrays to profile mRNAs, we identified IAA-Ala Resistant3 (IAR3) as a new target of miR167a. As expected, IAR3 mRNA was cleaved at the miR167a complementary site and under high osmotic stress miR167a levels decreased, whereas IAR3 mRNA levels increased. IAR3 hydrolyzes an inactive form of auxin (indole-3-acetic acid [IAA]-alanine) and releases bioactive auxin (IAA), a central phytohormone for root development. In contrast with the wild type, iar3 mutants accumulated reduced IAA levels and did not display high osmotic stress-induced root architecture changes. Transgenic plants expressing a cleavage-resistant form of IAR3 mRNA accumulated high levels of IAR3 mRNAs and showed increased lateral root development compared with transgenic plants expressing wild-type IAR3. Expression of an inducible noncoding RNA to sequester miR167a by target mimicry led to an increase in IAR3 mRNA levels, further confirming the inverse relationship between the two partners. Sequence comparison revealed the miR167 target site on IAR3 mRNA is conserved in evolutionarily distant plant species. Finally, we showed that IAR3 is required for drought tolerance.
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MESH Headings
- Amidohydrolases/genetics
- Amidohydrolases/metabolism
- Arabidopsis/genetics
- Arabidopsis/growth & development
- Arabidopsis/physiology
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/metabolism
- Biological Evolution
- Droughts
- Gene Expression Profiling
- Gene Expression Regulation, Plant/genetics
- High-Throughput Nucleotide Sequencing
- Hydroponics
- Indoleacetic Acids/metabolism
- MicroRNAs/genetics
- MicroRNAs/metabolism
- Models, Biological
- Oligonucleotide Array Sequence Analysis
- Osmosis
- Phenotype
- Plant Growth Regulators/metabolism
- Plant Leaves/genetics
- Plant Leaves/growth & development
- Plant Leaves/physiology
- Plant Roots/genetics
- Plant Roots/growth & development
- Plant Roots/physiology
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Plant/genetics
- RNA, Plant/metabolism
- Sequence Analysis, DNA
- Stress, Physiological/genetics
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Affiliation(s)
- Natsuko Kinoshita
- Laboratory of Plant Molecular Biology, The Rockefeller University, New York, NY 10065, USA
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45
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de la Iglesia F, Martínez F, Hillung J, Cuevas JM, Gerrish PJ, Daròs JA, Elena SF. Luria-delbruck estimation of turnip mosaic virus mutation rate in vivo. J Virol 2012; 86:3386-8. [PMID: 22238294 PMCID: PMC3302333 DOI: 10.1128/jvi.06909-11] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 12/29/2011] [Indexed: 11/20/2022] Open
Abstract
A potential drawback of recent antiviral therapies based on the transgenic expression of artificial microRNAs is the ease with which viruses may generate escape mutations. Using a variation of the classic Luria-Delbrück fluctuation assay, we estimated that the spontaneous mutation rate in the artificial microRNA (amiR) target of a plant virus was ca. 6 × 10(-5) per replication event.
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Affiliation(s)
- Francisca de la Iglesia
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, València, Spain
| | - Fernando Martínez
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, València, Spain
| | - Julia Hillung
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, València, Spain
| | - José M. Cuevas
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, València, Spain
| | - Philip J. Gerrish
- Center for Theoretical and Evolutionary Immunology, University of New Mexico, Albuquerque, New Mexico, USA
| | - José-Antonio Daròs
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, València, Spain
| | - Santiago F. Elena
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, València, Spain
- The Santa Fe Institute, Santa Fe, New Mexico, USA
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