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Alexander V Karasev - One of the best experts on this subject based on the ideXlab platform.
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the recombinant Potato Virus Y pvY strain pvYntn identified in Potato fields in victoria southeastern australia
Plant Disease, 2020Co-Authors: Mariana Rodriguezrodriguez, Stewart M. Gray, Mohamad Chikhali, Steven B Johnson, Nellie Malseed, Nigel S Crump, Alexander V KarasevAbstract:Potato Virus Y (PVY) is one of the main Viruses affecting Potato in Australia. However, molecular characterization of PVY isolates circulating in Potato in different states of Australia has not Yet been thoroughlY conducted. OnlY nonrecombinant isolates of three biological PVY strains collected from Potato were reported previouslY from Western Australia and one from Queensland. Here, PVY isolates collected from seed Potato originating in Victoria, Australia, and printed on FTA cards, were subjected to strain tYping bY RT-PCR, with three isolates subjected to whole genome sequencing. All the 59 PVY isolates detected during two growing seasons were identified to be recombinants based on two RT-PCR assaYs. No nonrecombinant PVY isolates were identified. All the RT-PCR tYped isolates belonged to the PVYNTN strain. Sequence analYsis of the whole genomes of three isolates suggested a single introduction of the PVYNTN strain to Australia but provided no clues as to where this introduction originated. Given the association of the PVYNTN strain with Potato tuber damage, growers in Australia should implement appropriate strategies to manage PVYNTN in Potato.
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Genetic diversitY of Potato Virus Y (PVY): sequence analYses reveal ten novel PVY recombinant structures
Archives of Virology, 2018Co-Authors: Kelsie J Green, Celeste J Brown, Alexander V KarasevAbstract:The Potato Virus Y (PVY) complex includes five non-recombinant strains and a growing number of recombinants. Up to now, the bulk of these PVY recombinants were found to be composed of genome segments coming from onlY two “parental” genomes, PVY^O and PVY^Eu-N, with a small minoritY including segments from other parents, e.g. PVY^C, PVY^NA-N, and a segment of the recombinant strain PVY-NE11. Here, comprehensive analYses of 396 whole genomes of PVY isolates from 34 countries and a varietY of hosts revealed 28 isolates to be rare or novel recombinants. When subjected to a thorough recombination analYsis, these 28 PVY isolates were found to represent 25 poorlY sampled PVY recombinant structures, ten of which had not been recognized previouslY. Nine of the ten novel structures carried parental sequences from PVY^NA-N or PVY-NE11 strains recombined with PVY^O and PVY^Eu-N sequences, while seven of the new structures contained sequences from three different parents. The number of known PVY recombinant patterns now stands at thirtY six. These recombinant structures present a challenge for PVY strain tYping, but maY shed light on interactions between PVY and host resistance genes.
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phYlogenetic studY of recombinant strains of Potato Virus Y
Virology, 2017Co-Authors: Kelsie J Green, Stewart M. Gray, Celeste J Brown, Alexander V KarasevAbstract:Potato Virus Y (PVY) exists as a complex of strains, including a growing number of recombinants. Evolution of PVY proceeds through accumulation of mutations and more rapidlY through recombination. Here, the role of recombination in PVY evolution and the origin of common PVY recombinants were studied through whole genome analYsis of 119 newlY sequenced PVY isolates largelY from U.S. Potato, and subsequent combined phYlogenetic and recombination analYses with an additional 166 whole PVY genomes from the GenBank database. Two novel PVYC recombinants were sequenced and identified, along with one novel PVYN:O recombinant. Sequence diversitY in the parental sequences made it possible to trace the origins of all recombinant tYpes of PVY, which also showed remarkable sequence diversitY in most cases. The results suggested that the common recombinant PVY strains originated more than once, from different parental sequences.
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molecular characterization of recombinant strains of Potato Virus Y from saudi arabia
Plant Disease, 2016Co-Authors: Mohamad Chikhali, Hayam Alruwaili, Dalton Vander Pol, Alexander V KarasevAbstract:Potato Virus Y (PVY) exists as a complex of strains, manY of which are recombinants. The practical importance of PVY recombinant strains has increased due to their abilitY to induce Potato tuber necrotic ring spot disease (PTNRD) that seriouslY affects tuber qualitY. In Saudi Arabia, Potato production has increased fivefold during the last three decades, reaching 460,000 tons per Year. Although PVY has been reported as one of the main Viruses affecting Potatoes, no information is available on PVY strains circulating in the countrY. In August 2014, a surveY was conducted in a seed Potato field at Al-Jouf, Saudi Arabia. PVY-positive samples selected based on visual sYmptoms and serological reactivitY were subjected to strain tYping using multiplex RT-PCR assaYs and were determined to represent recombinant PVY strains. Whole genome sequences were determined for two representative isolates, S2 and S9, through direct sequencing of a series of overlapping RT-PCR fragments for each isolate, and found to represent strains PVY-NE11 and PVYZ (SYR-III), respectivelY. One of the recombinant tYpes, SYR-III, was previouslY found in nearbY SYria and Jordan, but the second recombinant, PVY-NE11, was found before onlY in the United States. Both recombinants, PVY-NE11 and SYR-III, were previouslY found associated with PTNRD and thought to be rare. The current identification of PVY-NE11 and SYR-III in seed Potato in a new geographic region suggests that these recombinants maY not be as rare as previouslY believed. This is the first report on the occurrence of recombinant strains of PVY in Potato in Saudi Arabia, and the first report on the PVY-NE11 strain of PVY found in Potato outside of the United States.
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screening Potato cultivars for new sources of resistance to Potato Virus Y
American Journal of Potato Research, 2015Co-Authors: Jenny S Rowley, Stewart M. Gray, Alexander V KarasevAbstract:Potato Virus Y (PVY) strains have been defined based on genetic reactions in Potato indicators expressing hYpersensitive reaction (HR) response due to the presence of three different N genes, and also based on genomic information. Nine strains are known currentlY, with five PVY strains defined biologicallY, PVYO, PVYC, PVYZ, PVYN, and PVYE. The genetic background of the majoritY of North American Potato cultivars has so far been poorlY characterized for the presence of N genes inducing HR towards different PVY strains. Here, the HR response was studied in eight Potato cultivars, elicited bY five strains of PVY circulating in North America. These PVY isolates included representative isolates of PVYN-Wi, PVYNA-N, PVYO, PVYZ, and PVYN strains. Potato cultivars tested included Russet Burbank, Russet Norkotah, ShepodY, Ranger Russet, Western Russet, Alturas, Rio Grande Russet, and Yukon Gem, grown in the U.S., and standard indicators Desiree and Maris Bard with the known genetic background. Three additional strains, PVYN:O, PVY-NE11, and PVYE, were tested on Yukon Gem. Virus-free Potato plants were mechanicallY inoculated with PVY inoculum, and local and sYstemic foliar sYmptoms were observed for 8 weeks post-inoculation under different climate-controlled conditions. Virus status of the inoculated plants was tested starting at 3 weeks post-inoculation, bY serotYpe-specific ELISA and RT-PCR, in order to monitor successful infections and confirm the identitY of the inoculated PVY isolate. This sYstematic approach allowed us to identifY NY tbr and Nz tbr genes present in several North American cultivars. Two more new, putative N genes were postulated to be expressed in the cultivar Yukon Gem, and one additional putative N gene was postulated to be expressed in two cultivars, Yukon Gem and Rio Grande Russet. These N genes maY represent valuable sources of resistance against multiple strains of PVY.
Stewart M. Gray - One of the best experts on this subject based on the ideXlab platform.
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the recombinant Potato Virus Y pvY strain pvYntn identified in Potato fields in victoria southeastern australia
Plant Disease, 2020Co-Authors: Mariana Rodriguezrodriguez, Stewart M. Gray, Mohamad Chikhali, Steven B Johnson, Nellie Malseed, Nigel S Crump, Alexander V KarasevAbstract:Potato Virus Y (PVY) is one of the main Viruses affecting Potato in Australia. However, molecular characterization of PVY isolates circulating in Potato in different states of Australia has not Yet been thoroughlY conducted. OnlY nonrecombinant isolates of three biological PVY strains collected from Potato were reported previouslY from Western Australia and one from Queensland. Here, PVY isolates collected from seed Potato originating in Victoria, Australia, and printed on FTA cards, were subjected to strain tYping bY RT-PCR, with three isolates subjected to whole genome sequencing. All the 59 PVY isolates detected during two growing seasons were identified to be recombinants based on two RT-PCR assaYs. No nonrecombinant PVY isolates were identified. All the RT-PCR tYped isolates belonged to the PVYNTN strain. Sequence analYsis of the whole genomes of three isolates suggested a single introduction of the PVYNTN strain to Australia but provided no clues as to where this introduction originated. Given the association of the PVYNTN strain with Potato tuber damage, growers in Australia should implement appropriate strategies to manage PVYNTN in Potato.
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transmission modes affect the population structure of Potato Virus Y in Potato
PLOS Pathogens, 2020Co-Authors: Stewart M. Gray, S. F. Elena, Washington Luis Da Silva, Denis Kutnjak, James J GiovannoniAbstract:Transmission is a crucial part of a viral life cYcle and transmission mode can have an important impact on Virus biologY. It was demonstrated that transmission mode can influence the virulence and evolution of a Virus; however, few empirical data are available to describe the direct underlYing changes in Virus population structure dYnamics within the host. Potato Virus Y (PVY) is an RNA Virus and one of the most damaging pathogens of Potato. It comprises several geneticallY variable strains that are transmitted between plants via different transmission modes. To investigate how transmission modes affect the within-plant viral population structure, we have used a deep sequencing approach to examine the changes in the genetic structure of populations (in leaves and tubers) of three PVY strains after successive passages bY horizontal (aphid and mechanical) and vertical (via tubers) transmission modes. Nucleotide diversities of viral populations were significantlY influenced bY transmission modes; lineages transmitted bY aphids were the least diverse, whereas lineages transmitted bY tubers were the most diverse. Differences in nucleotide diversities of viral populations between leaves and tubers were transmission mode-dependent, with higher diversities in tubers than in leaves for aphid and mechanicallY transmitted lineages. Furthermore, aphid and tuber transmissions were shown to impose stronger genetic bottlenecks than mechanical transmission. To better understand the structure of Virus populations within the host, transmission mode, movement of the Virus within the host, and the number of replication cYcles after transmission event need to be considered. CollectivelY, our results suggest a significant impact of Virus transmission modes on the within-plant diversitY of Virus populations and provide quantitative fundamental data for understanding how transmission can shape Virus diversitY in the natural ecosYstems, where different transmission modes are expected to affect Virus population structure and consequentlY its evolution.
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germplasm with resistance to Potato Virus Y derived from solanum chacoense clones m19 39 7 and m20 xd3
American Journal of Potato Research, 2019Co-Authors: Ana Cristina Fulladolsa, Stewart M. Gray, Jonathan L Whitworth, Amy O Charkowski, Xingkui Cai, Shelley JanskyAbstract:Potato Virus Y (PVY) causes one of the most serious and widespread diseases in North America. In recent Years, the Virus has become increasinglY difficult to control. Durable dominant genes for resistance to PVY exist in Potato germplasm and provide an effective control strategY. This paper describes a Solanum chacoense clone (M19) that is homozYgous for a PVY resistance gene. The gene is linked to a previouslY published marker for RYchc found in Solanum chacoense. M19 was crossed with a diploid S. tuberosum clone to produce an adapted clone carrYing the resistance gene. This hYbrid clone is named M20. M20 tuberizes in the field, producing round tubers with white skin and flesh and moderate size. M20 is resistant to PVYO, PVYN:O, and PVYNTN. Both M19 and M20 are female and male fertile, so theY are being released as sources of PVY resistance for breeding programs.
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phYlogenetic studY of recombinant strains of Potato Virus Y
Virology, 2017Co-Authors: Kelsie J Green, Stewart M. Gray, Celeste J Brown, Alexander V KarasevAbstract:Potato Virus Y (PVY) exists as a complex of strains, including a growing number of recombinants. Evolution of PVY proceeds through accumulation of mutations and more rapidlY through recombination. Here, the role of recombination in PVY evolution and the origin of common PVY recombinants were studied through whole genome analYsis of 119 newlY sequenced PVY isolates largelY from U.S. Potato, and subsequent combined phYlogenetic and recombination analYses with an additional 166 whole PVY genomes from the GenBank database. Two novel PVYC recombinants were sequenced and identified, along with one novel PVYN:O recombinant. Sequence diversitY in the parental sequences made it possible to trace the origins of all recombinant tYpes of PVY, which also showed remarkable sequence diversitY in most cases. The results suggested that the common recombinant PVY strains originated more than once, from different parental sequences.
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Potato Virus Y transmission efficiencY from Potato infected with single or multiple Virus strains
Phytopathology, 2017Co-Authors: Shaonpius Mondal, Jonathan L Whitworth, Yuhsuan Lin, J E Carroll, Erik J Wenninger, Nilsa A Bosqueperez, Pamela J S Hutchinson, Sanford D Eigenbrode, Stewart M. GrayAbstract:There has been a recent shift in the prevalence of Potato Virus Y (PVY) strains affecting Potato with the ordinarY strain PVYO declining and the recombinant strains PVYNTN and PVYN:O emerging in the United States. Multiple PVY strains are commonlY found in Potato fields and even in individual plants. Factors contributing to the emergence of the recombinant strains are not well defined but differential aphid transmission of strains from single and mixed infections maY plaY a role. We found that the transmission efficiencies bY MYzus persicae, the green peach aphid, of PVYNTN, PVYN:O, and PVYO varied depending on the Potato cultivar serving as the Virus source. Overall transmission efficiencY was highest from sources infected with three Virus strains, whereas transmission from sources infected with one or two Virus strains was not significantlY different. Two strains were concomitantlY transmitted bY individual aphids from manY of the mixed-source combinations, especiallY if PVYO was present. Triple-strain ...
Benoit Moury - One of the best experts on this subject based on the ideXlab platform.
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Potato Virus Y (PotYviridae)
2021Co-Authors: Laurent Glais, Benoit MouryAbstract:Potato Virus Y (PVY) is the tYpe species member of the genus PotYVirus, familY PotYviridae. Its natural host range mainlY comprises plants in the familY Solanaceae. PVY is highlY variable, with recognized strains and variants. Also two main serotYpes O-C and N can be distinguished. Full genome sequences of numerous isolates are known (540). PVY is transmitted bY sixtY-five species of aphids. MYzus persicae has the highest vector efficiencY, though manY other species such as cereal aphids can also be involved in epidemics. Control strategies are based on breeding for resistance and use of certified Potato seeds.
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a new lineage sheds light on the evolutionarY historY of Potato Virus Y
Molecular Plant Pathology, 2010Co-Authors: Benoit MouryAbstract:Potato Virus Y (PVY) is one of the rare plant Viruses for which some biological traits (host range and sYmptomatologY) are highlY correlated with phYlogenY, allowing the reconstruction of the evolutionarY historY of these traits. In this article, a new lineage of PVY isolates from Chile is described, showing unique genomic and biological properties. This lineage was found to be the sister group of all other PVY isolates and helped in the reconstruction of the ancestral traits and evolutionarY historY of PVY, suggesting that veinal necrosis in tobacco is an ancestral state and that adaptation to pepper (Capsicum spp.) and Potato (Solanum tuberosum) has been modified several times during PVY historY.
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Potato Virus Y
Encyclopedia of Virology (Third Edition), 2008Co-Authors: C Kerlan, Benoit MouryAbstract:Potato Virus Y (PVY) is the tYpe member of the genus PotYVirus, which contains some of the most damaging plant Viruses. Its natural host range comprises major crops (Potato, pepper, tomato, tobacco), less important cultivated plants, and numerous species of weeds mainlY in the familY Solanaceae. Host plants belong to 495 species and 31 families. PVY is highlY variable, manY Potato strains (PVYO, PVYC, PVYN) and variants (PVYNTN, PVYNW, PVYN:O), pepper pathotYpes [(0), (0,1), (0,1,2)], tobacco strains (MSMR, MSNR, NSNR) being recognized. Two main serotYpes O–C and N can be distinguished using monoclonal antibodies. Full genome sequences of more than ten isolates are known and molecular variabilitY intensivelY studied resulting in separating three genetic strains (O, N, C). PVY has long been a model for studies of nonpersistent transmission bY aphids. SeventY species of aphids were shown to transmit PVY. MYzus persicae has the highest vector efficiencY and is responsible for most of natural spread of PVY, though manY other species such as cereal aphids could also be involved in epidemics. Control strategies are based on breeding for resistance, use of certified Potato seeds, and quarantine regulations to prevent spread of nonindigenous strains or variants.
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different mutations in the genome linked protein vpg of Potato Virus Y confer virulence on the pvr23 resistance in pepper
Molecular Plant-microbe Interactions, 2006Co-Authors: Valerie Ayme, Mireille Jacquemond, Sylvie Souche, Carole Caranta, A Palloix, Joel Chadœuf, Benoit MouryAbstract:Five different amino acid substitutions in the VPg of Potato Virus Y were shown to be independentlY responsible for virulence toward pvr23 resistance gene of pepper. A consequence of these multiple mutations toward virulence involving single nucleotide substitutions is a particularlY high frequencY of resistance breaking (37% of inoculated plants from the first inoculation) and suggests a potentiallY low durabilitY of pvr23 resistance. These five mutants were observed with significantlY different frequencies, one of them being overrepresented. Genetic drift alone could not explain the observed distribution of virulent mutants. More plausible scenarios were obtained bY taking into account either the relative substitution rates, the relative fitness of the mutants in pvr23 pepper plants, or both.
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mutations in Potato Virus Y genome linked protein determine virulence toward recessive resistances in capsicum annuum and lYcopersicon hirsutum
Molecular Plant-microbe Interactions, 2004Co-Authors: Benoit Moury, Caroline Morel, Elisabeth Johansen, Laurent Guilbaud, Sylvie Souche, Valerie Ayme, Carole Caranta, A Palloix, Mireille JacquemondAbstract:The recessive resistance genes pot-1 and pvr2 in LYcopersicon hirsutum and Capsicum annuum, respectivelY, control Potato Virus Y (PVY) accumulation in the inoculated leaves. Infectious cDNA molecules from two PVY isolates differing in their virulence toward these resistances were obtained using two different strategies. Chimeras constructed with these cDNA clones showed that a single nucleotide change corresponding to an amino acid substitution (Arg119His) in the central part of the viral protein genome-linked (VPg) was involved in virulence toward the pot-1 resistance. On the other hand, 15 nucleotide changes corresponding to five putative amino acid differences in the same region of the VPg affected virulence toward the pvr21 and pvr22 resistances. Substitution models identified six and five codons within the central and C terminal parts of the VPg for PVY and for the related potYVirus Potato Virus A, respectivelY, which undergo positive selection. This suggests that the role of the VPg-encoding region ...
Mireille Jacquemond - One of the best experts on this subject based on the ideXlab platform.
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different mutations in the genome linked protein vpg of Potato Virus Y confer virulence on the pvr23 resistance in pepper
Molecular Plant-microbe Interactions, 2006Co-Authors: Valerie Ayme, Mireille Jacquemond, Sylvie Souche, Carole Caranta, A Palloix, Joel Chadœuf, Benoit MouryAbstract:Five different amino acid substitutions in the VPg of Potato Virus Y were shown to be independentlY responsible for virulence toward pvr23 resistance gene of pepper. A consequence of these multiple mutations toward virulence involving single nucleotide substitutions is a particularlY high frequencY of resistance breaking (37% of inoculated plants from the first inoculation) and suggests a potentiallY low durabilitY of pvr23 resistance. These five mutants were observed with significantlY different frequencies, one of them being overrepresented. Genetic drift alone could not explain the observed distribution of virulent mutants. More plausible scenarios were obtained bY taking into account either the relative substitution rates, the relative fitness of the mutants in pvr23 pepper plants, or both.
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mutations in Potato Virus Y genome linked protein determine virulence toward recessive resistances in capsicum annuum and lYcopersicon hirsutum
Molecular Plant-microbe Interactions, 2004Co-Authors: Benoit Moury, Caroline Morel, Elisabeth Johansen, Laurent Guilbaud, Sylvie Souche, Valerie Ayme, Carole Caranta, A Palloix, Mireille JacquemondAbstract:The recessive resistance genes pot-1 and pvr2 in LYcopersicon hirsutum and Capsicum annuum, respectivelY, control Potato Virus Y (PVY) accumulation in the inoculated leaves. Infectious cDNA molecules from two PVY isolates differing in their virulence toward these resistances were obtained using two different strategies. Chimeras constructed with these cDNA clones showed that a single nucleotide change corresponding to an amino acid substitution (Arg119His) in the central part of the viral protein genome-linked (VPg) was involved in virulence toward the pot-1 resistance. On the other hand, 15 nucleotide changes corresponding to five putative amino acid differences in the same region of the VPg affected virulence toward the pvr21 and pvr22 resistances. Substitution models identified six and five codons within the central and C terminal parts of the VPg for PVY and for the related potYVirus Potato Virus A, respectivelY, which undergo positive selection. This suggests that the role of the VPg-encoding region ...
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Evidence for diversifYing selection in Potato Virus Y and in the coat protein of other potYViruses
Journal of General Virology, 2002Co-Authors: Benoit Moury, Caroline Morel, Elisabeth Ida Johansen, Mireille JacquemondAbstract:The modes of evolution of the proteins of Potato Virus Y were investigated with a maximum-likelihood method based on estimation of the ratio between non-sYnonYmous and sYnonYmous substitution rates. Evidence for diversifYing selection was obtained for the 6K2 protein (one amino acid position) and coat protein (24 amino acid positions). Amino acid sites in the coat proteins of other potYViruses (Bean Yellow mosaic Virus, Yam mosaic Virus) were also found to be under diversifYing selection. Most of the sites belonged to the N-terminal domain, which is exposed to the exterior of the virion particle. Several of these amino acid positions in the coat proteins were shared between some of these three potYViruses. Identification of diversifYing selection events in these different proteins will help to unravel their biological functions and is essential to an understanding of the evolutionarY constraints exerted on the potYVirus genome. The hYpothesis of a link between evolutionarY constraints due to host plants and occurrence of diversifYing selection is discussed.
Jari P. T. Valkonen - One of the best experts on this subject based on the ideXlab platform.
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Resistance to Potato Virus Y in Potato
Potato virus Y: biodiversity pathogenicity epidemiology and management, 2017Co-Authors: Jari P. T. Valkonen, Christiane Gebhardt, Ewa Zimnoch-guzowska, Kazuo N. WatanabeAbstract:Growing Potato cultivars resistant to Potato Virus Y (PVY) offers the easiest and the most cost-effective solution to prevent the losses caused bY PVY. Genes for resistance to PVY can be found in wild and cultivated Potato species. Resistance genes functioning on the “gene-for-gene” basis are commonlY used in breeding for resistance to PVY, because of their dominant and simple inheritance. Ten genes for resistance to PVY have been mapped to four Potato genome segments on chromosomes IV, IX, XI and XII. Genes for hYpersensitive resistance (HR) are usuallY PVY strain-specific, whereas the genes for extreme resistance (ER) are effective against a broad spectrum of PVY strains. The need for broad-spectrum resistance to PVY has been widelY realized since the turn of the millennium when new PVY strains able to overcome strain-specific resistance to the common PVY strains became prevalent in Potato crops worldwide. Field resistance to PVY is widelY present in Potato cultivars and based almost exclusivelY on minor genes contributing small effects. Marker-assisted selection provides an efficient approach for the selection of traits governed bY major genes or quantitative trait loci (QTLs) with large effects. GeneticallY engineered resistance based on RNA silencing, the basal antiviral defense sYstem of plants, is another option to protect Potatoes against PVY.
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Genetic diversitY of Potato Virus Y infecting tobacco crops in China.
Phytopathology, 2011Co-Authors: Yan-ping Tian, Jinliang Liu, C. L. Zhang, Y. Y. Liu, B. Wang, Z. K. Guo, Jari P. T. ValkonenAbstract:ABSTRACT Genetic variabilitY of Potato Virus Y (PVY) isolates infecting Potato has been characterized but little is known about genetic diversitY of PVY isolates infecting tobacco crops. In this studY, PVY isolates were collected from major tobacco-growing areas in China and single-lesion isolates were produced bY serial inoculation on Chenopodium amaranticolor. Most isolates (88%) caused sYstemic veinal necrosis sYmptoms in tobacco. Of these, 16 isolates contained a PVYO-like coat protein (CP) and PVYN-like helper component proteinase (HC-pro) and, in this respect, were similar to the PVYN-Wi, PVYN:O, and PVY-HN2 isolates characterized from Potato in Europe, the United States, and China, respectivelY; two isolates contained a PVYO-like HC-pro and a PVYN-like CP; another two isolates had recombination junctions in the CP-encoding region. Both the HC-pro and CP of PVY were under negative selection as a whole; however, seven amino acids in HC-pro and six amino acids in CP were under positive selection. Sele...
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Discussion paper: The naming of Potato Virus Y strains infecting Potato
Archives of Virology, 2008Co-Authors: R. P. Singh, S. M. Gray, C Kerlan, R A C Jones, Jari P. T. Valkonen, Neil Boonham, J SchubertAbstract:Potato Virus Y (PVY) strain groups are based on host response and resistance gene interactions. The strain groups PVY(O), PVY(C) and PVY(N) are well established for the isolates infecting Potato in the field. A switch in the emphasis from host response to nucleotide sequence differences in the Virus genomes, detection of isolates recombining sequences of different strains, and the need to recognize isolates that cause necrotic sYmptoms in Potato tubers have led to the assignment of new acronYms, especiallY to isolates of the PVY(N) strain group. This discussion paper proposes that anY newlY found isolates should be described within the context of the original strain groups based on the original methods of distinguishing strains (i.e., tobacco and Potato assaYs involving use of 'differential' Potato cultivars). AdditionallY, sequence characterization of the complete genomes of isolates is highlY recommended. However, it is acceptable to amend the names of PVY isolates with additional, specific codes to show that the isolate differs at the molecular, serological or phenotYpic level from the tYpical strains within a strain group. The new isolates should preferablY not be named using geographical, cultivar, or place-association designations. Since manY new variants of PVY are being discovered, anY new static classification sYstem will be meaningless for the time being. A more sYstematic investigation and characterization of PVY from Potato at the biological and molecular levels should eventuallY result in a biologicallY meaningful genetic strain concept.
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mapping and marker assisted selection for a gene for extreme resistance to Potato Virus Y
Theoretical and Applied Genetics, 1997Co-Authors: J H Hamalainen, Jari P. T. Valkonen, Kazuo N. Watanabe, A Arihara, R L Plaisted, Eija Pehu, L Miller, S A SlackAbstract:The chromosomal location of the major gene RYadg controlling extreme resistance to Potato Virus Y (PVY) in Solanum tuberosum subsp. andigena was identified bY RFLP analYsis of a diploid Potato population. A total of 64 tomato and Potato RFLP markers were screened with the bulked segregant analYsis (BSA) on segregants extremelY resistant, hYpersensitive or susceptible to PVY. Four markers TG508, GP125, CD17 and CT168 at the proximal end of chromosome XI showed close linkage with extremelY resistant phenotYpes. TG508 was identified as the closest marker linked with the RYadg locus with the maximum map distance estimated as 2.0 cM. The 4 markers linked with the RYadg locus were tested on independent tetraploid and diploid Potato clones and were subsequentlY found useful for marker-assisted selection for plants containing RYadg.