| nucleotide sequence of the 3' terminal region of the rna of two filamentous grapevine viruses. | the 3' terminal region of grapevine virus a (gva) and grapevine virus b (gvb), encompassing 1883 and 2136 nucleotides, respectively, was sequenced by the deoxynucleotide chain termination method. three putative open reading frames (orf) were identified in both genomic viral rnas, denoted 1 to 3 in the 5' to 3' direction. orf 1 encoded a polypeptide with estimated m(r) of 31 kda (gva) and 36.5 kda (gvb), possessing the g/d motif of the "30 k superfamily" movement proteins, and showing good alignm ... | 1994 | 7944948 |
| sensitive detection of grapevine virus a, b, or leafroll-associated iii from viruliferous mealybugs and infected tissue by cdna amplification. | dna primers specific for grapevine virus a (gva), grapevine virus b (gvb) or grapevine leafroll-associated virus iii (glrav-iii) were constructed based on the nucleotide sequence of a segment of each viral genome. dna primers were utilized for cdna synthesis and polymerase chain reaction (pcr) amplification of a 430 bp fragment from extracts of gva-infected grapevine tissue or viruliferous mealybugs and 450 bp and 340 bp dna fragments from extracts of gvb and glrav-iii-infected grapevine tissues ... | 1994 | 8051225 |
| properties of a filamentous virus isolated from grapevines affected by corky bark. | a virus with highly flexuous filamentous particles c. 800 nm long, showing distinct transverse striations was isolated with high frequency (60%) by inoculation of nicotiana occidentalis with sap from grapevine accessions indexing positive for corky bark. the virus, for which the name grapevine virus b (gvb) is proposed, has an ssrna genome with mol. wt. of c. 2.5 x 10(6) da (c. 7600 nt) and coat protein subunits with mol. wt. of c 23,000 da. gvb has a very restricted herbaceous host range and wa ... | 1993 | 8503778 |
| grapevine berry inner necrosis, a new trichovirus: comparative studies with several known trichoviruses. | biological, morphological and serological properties of grapevine berry inner necrosis virus (ginv), the casual virus of grapevine berry inner necrosis disease occurring in japan, were compared with those of several known trichoviruses. host range and particle length of ginv were quite similar to those of apple chlorotic leaf spot trichovirus (aclsv). in ultrathin sections of the infected tissues, ginv particles existed in aggregated masses in the cytoplasm of vascular parenchyma and mesophyll c ... | 1997 | 9267448 |
| infectious rna transcripts from grapevine virus a cdna clone. | a full length cdna clone of grapevine virus a (gva) was constructed downstream from the bacteriophage t7 rna polymerase promoter. capped in vitro-transcribed rna was infectious in nicotiana benthamiana and n. clevelandii plants. symptoms induced by the rna transcripts or by the parental virus were indistinguishable. the infectivity of the in vitro-transcribed rna was confirmed by serological detection of the virus coat and movement proteins and by observation of virions by electron microscopy. t ... | 1999 | 10595415 |
| infectious cdna clones of two grapevine viruses. | full-length cdna copies of the genomes of grapevine virus a (gva) and grapevine virus b (gvb) under the control of bacteriophage t7 promoter have been synthesized, which were refractory to cloning in escherichia coli. however, both transcribed cdnas were infectious when mechanically inoculated to nicotiana plants. a full-length cdna copy of gvb was engineered in pcass2, a plasmid containing a partially duplicated copy of the ca35s promoter, but was rather unstable in escherichia coli. no infecti ... | 2000 | 10752561 |
| immunodetection and subcellular localization of the proteins encoded by orf 3 of grapevine viruses a and b. | polyclonal antisera were raised to escherichia coli-expressed orf3 products (putative movement proteins) of grapevine virus a (gva) and grapevine virus b (gvb) (genus vitivirus), and used for their immunodetection in infected plants. western blot analysis of subfractionated cellular compartments showed that the distribution of both proteins was comparable to that of plant virus movement proteins, as they were transiently present in a crude membrane fraction and accumulated in a cell wall-enriche ... | 2000 | 11003467 |
| orf 5 of grapevine virus a encodes a nucleic acid-binding protein and affects pathogenesis. | a previous functional analysis of the genome of grapevine virus a (gva) was not conclusive as to the role of open reading frame 5 (orf 5). this orf encodes a 10-kda protein (p10) carrying two distinct domains: a basic, arginine-rich domain and a zinc-finger domain. p10 was cloned and expressed in escherichia coli, and was shown by northwestern assays to interact with nucleic acids. in-frame deletion of the basic region abolished p10's nucleic acid-binding capability, whereas substitution of cyst ... | 2003 | 14618086 |
| diverse suppressors of rna silencing enhance agroinfection by a viral replicon. | launching the beet yellows virus (byv) minireplicon by agrobacterial delivery resulted in an unexpectedly low number of infected cells per inoculated leaf. this effect was due to a strong rna silencing response in the agroinfiltrated leaves. strikingly, ectopic co-expression of p21, a byv rna silencing suppressor, increased minireplicon infectivity by three orders of magnitude. mutational analysis demonstrated that this effect correlates with suppressor activity of p21. five diverse, heterologou ... | 2006 | 16300814 |
| identification, detection and transmission of a new vitivirus from mentha. | mentha x gracilis 'variegata' is an ornamental clone with a phenotype caused by virus infection. several clones were ordered from mail-order nurseries in an attempt to identify a virus consistently associated with symptoms. one of these clones did not exhibit typical 'variegata' symptoms, and steps were taken to identify any agents causing the 'off-type' symptoms. one of the viruses identified in the atypical 'variegata' clone is a previously unknown virus, a member of the family flexiviridae. s ... | 2007 | 17680328 |
| a universal expression/silencing vector in plants. | a universal vector (il-60 and auxiliary constructs), expressing or silencing genes in every plant tested to date, is described. plants that have been successfully manipulated by the il-60 system include hard-to-manipulate species such as wheat (triticum duram), pepper (capsicum annuum), grapevine (vitis vinifera), citrus, and olive (olea europaea). expression or silencing develops within a few days in tomato (solanum lycopersicum), wheat, and most herbaceous plants and in up to 3 weeks in woody ... | 2007 | 17905866 |
| identification and characterization of a new vitivirus from grapevine. | new virus-like sequences, tvaq7 and tvp15, were found in a japanese grapevine accession of oky-aq7 (cv. aki queen) and of oky-p15 (cv. pione) by nested rt-pcr to simultaneously amplify a segment of the rna-dependent rna polymerase (rdrp) gene from members of the genera vitivirus and foveavirus. the tvaq7 genome, except for an exact 5' terminus, is composed of about 7.6 kb containing five potential open reading frames. the genomic organization resembles those of grapevine virus a and other known ... | 2008 | 18784974 |
| real-time rt-pcr (taqman) assays for the detection of viruses associated with rugose wood complex of grapevine. | real-time taqman rt-pcr (taqman rt-pcr) assays were developed to detect the viruses associated with rugose wood complex of grapevines. the viruses detected were rupestris stem pitting-associated virus in the genus foveavirus, grapevine virus a, grapevine virus b and grapevine virus d in the genus vitivirus. the coat protein was found to be the most conserved gene within the viral species, therefore, the primers and probes for taqman rt-pcr assays were designed from the multiple alignment of the ... | 2008 | 18848580 |
| grapevine virusa-mediated gene silencing in nicotiana benthamiana and vitis vinifera. | virus-induced gene silencing (vigs) is an attractive approach for studying gene function. although the number of virus vectors available for use in vigs experiments has increased in recent years, most of these vectors are applied in annual or herbaceous plants. the aim of this work was to develop a vigs vector based on the grapevine virus a (gva), which is a member of the genus vitivirus, family flexiviridae. the gva vector was used to silence the endogenous phytoene desaturase (pds) gene in nic ... | 2009 | 19010356 |
| deep sequencing analysis of viruses infecting grapevines: virome of a vineyard. | double stranded rna, isolated from 44 pooled randomly selected vines from a diseased south african vineyard, has been used in a deep sequencing analysis to build a census of the viral population. the dsrna was sequenced in an unbiased manner using the sequencing-by-synthesis technology offered by the illumina genome analyzer ii and yielded 837 megabases of metagenomic sequence data. four known viral pathogens were identified. it was found that grapevine leafroll-associated virus 3 (glrav-3) is t ... | 2010 | 20172578 |
| the grapevine-infecting vitiviruses, with particular reference to grapevine virus a. | a number of vitiviruses infect grapevine, arguably the most important fruit crop, and the host from which they derive their genus name. in contrast to most grapevine viruses, the etiological role of these viruses is unclear, albeit that they are associated with several well-known - and a number of emerging - diseases of grapevine. here, we review the genus vitivirus, with special reference to its most omnipresent member, grapevine virus a. we discuss the latest taxonomic status of the genus, as ... | 2011 | 21779907 |
| the complete nucleotide sequence of potato virus t. | potato virus t (pvt), a member of an unassigned species in the family flexiviridae, has a genome 6,539 nt in size with three orfs coding for replication-associated proteins (185 kda, orf 1), movement protein (40 kda, orf 2) and coat protein (24 kda, orf 3), respectively. pvt differs from the type members of all genera of the family flexiviridae with a 30k-type movement protein and is phylogenetically distant from all of these viruses, least so from grapevine virus a (gva, genus vitivirus), with ... | 2009 | 19115033 |
| the orf3-encoded proteins of vitiviruses gva and gvb induce tubule-like and punctate structures during virus infection and localize to the plasmodesmata. | the genomic rna of vitiviruses contains 5 open reading frames (orf). orf3 encodes a protein to which the function of a movement protein (mp) was assigned, based on sequence homology with other viral proteins. the aim of the research described in this paper was to gain further insight in distribution profile of the orf3 product encoded by the vitiviruses grapevine virus a (gva) and grapevine virus b (gvb). expression of the gva mp-gfp fusion protein via the virus genome in nicotiana benthamiana l ... | 2011 | 22051060 |
| serological detection of grapevine virus a using antiserum to a nonstructural protein, the putative movement protein. | abstract grapevine virus a (gva) is implicated in the etiology of the rugose wood disease. the coat protein (cp) and the putative movement protein (mp) genes of gva were cloned and expressed in escherichia coli and used to produce antisera. both the cp and the mp were detected with their corresponding antisera in gva-infected nicotiana benthamiana. the mp was first detected at an early stage of the infection, 6 to 12 h after inoculation, and the cp was detected 2 to 3 days after inoculation. the ... | 1997 | 18945038 |
| simultaneous detection of nine grapevine viruses by multiplex reverse transcription-polymerase chain reaction with coamplification of a plant rna as internal control. | abstract a multiplex reverse transcription-polymerase chain reaction (mrt-pcr) was developed for simultaneous detection of nine grapevine viruses: arabis mosaic virus, grapevine fanleaf virus, grapevine virus a, grapevine virus b, rupestris stem pitting-associated virus, grapevine fleck virus, grapevine leafroll-associated virus-1, -2, and -3, in combination with a plant rna internal control used as an indicator of the effectiveness of rna extraction and rt-pcr. primers were designed from conser ... | 2006 | 18943959 |
| tepovirus, a novel genus in the family betaflexiviridae. | tepovirus is a new monotypic genus of plant viruses typified by potato virus t (pvt), a virus with helically constructed filamentous particles that are 640 nm long, previously classified as unassigned species in the family betaflexiviridae. virions have a single-stranded positive-sense polyadenylated rna genome that is 6.5 kb in size, and a single type of coat protein with a size of 24 kda. the viral genome contains three slightly overlapping orfs encoding, respectively, the replication-related ... | 2012 | 22592959 |
| molecular divergence of grapevine virus a (gva) variants associated with shiraz disease in south africa. | shiraz disease (sd) is a highly destructive, insect-transmitted disease of noble grapevine cultivars, such as shiraz and merlot, in south africa. earlier studies revealed that, of the three molecular groups of gva that were detected in local vineyards, variants of group ii are closely associated with expression of this disease, and variants of group iii are commonly present in gva-infected sd-negative plants [goszczynski, d.e., 2007. single-strand conformation polymorphism (sscp), cloning and se ... | 2008 | 18822325 |
| post-transcriptional gene silencing and virus resistance in nicotiana benthamiana expressing a grapevine virus a minireplicon. | grapevine virus a (gva) is closely associated with the economically important rugose-wood disease of grapevine. in an attempt to develop gva resistance, we made a gfp-tagged gva-minireplicon and utilized it as a tool to consistently activate rna silencing. launching the gva-minireplicon by agroinfiltration delivery resulted in a strong rna silencing response. in light of this finding, we produced transgenic nicotiana benthamiana plants expressing the gva-minireplicon, which displayed phenotypes ... | 2009 | 18821075 |
| transgenes consisting of a dsrna of an rnai suppressor plus the 3' utr provide resistance to citrus tristeza virus sequences in nicotiana benthamiana but not in citrus. | in an attempt to utilize post-transcriptional gene silencing (ptgs) as a means to impart resistance against citrus tristeza virus (ctv) into citrus plants, the p23 + 3'utr sequence (p23u) of the vt strain of ctv was engineered to fold into a double-stranded (ds) rna structure. the resulting construct (p23ui) was introduced into nicotiana benthamiana and alemow (citrus macrophylla) plants by agrobacterium-mediated transformation. transgenic p23ui- n. benthamiana were resistant to infection with a ... | 2006 | 16991003 |
| identification of an rna-silencing suppressor in the genome of grapevine virus a. | higher plants use post-transcriptional gene silencing (ptgs), an rna-degradation system, as a defence mechanism against viral infections. to counteract this, plant viruses encode and express ptgs suppressor proteins. four of the five proteins encoded by the grapevine virus a (gva) genome were screened using a green fluorescent protein (gfp)-based transient expression assay, and the expression product of orf5 (protein p10) was identified as a suppressor of silencing. orf5 p10 suppressed local and ... | 2006 | 16847135 |
| efficient methods for sample processing and cdna synthesis by rt-pcr for the detection of grapevine viruses and viroids. | template preparation is important in reverse-transcription polymerase chain reaction (rt-pcr)-based detection methods. a tissuelyser with tungsten carbide beads was used for simultaneous processing of up to 48 samples under the same conditions in the development of a simple and rapid procedure to prepare a plant extract for rt reaction. a sandpaper method was also developed by which wood tissue of dormant cuttings could be macerated easily to process with minimal time and effort. it was also dem ... | 2006 | 16510197 |
| engineering the genome of grapevine virus a into a vector for expression of proteins in herbaceous plants. | grapevine virus a (gva), a species of the genus vitivirus, consists of a approximately 7.4 kb single-stranded rna genome of positive polarity, organized into five open reading frames (orfs). in addition to grape varieties, gva infects nicotiana benthamiana plants and protoplasts. we engineered the genome of gva as a vector that includes duplication of homologous sequences that contain the promoter of the movement protein (mp) sgrna, supplemented by enzymatic restriction sites to be used as a con ... | 2006 | 16298435 |
| comparison of three techniques for detection of grapevine leafroll-associated virus 1. | thirty seven plants of grapevine from the research station of viticulture, karlstejn was examined for the presence of leafroll viruses. grapevine leafroll-associated virus 1 (glrav-1) was detected in the grapevines plants tested using double-antibody sandwich elisa (das-elisa), rt-pcr and molecular hybridization with non-radioactive rna probes. both molecular methods were based on a detection of the glrav-1 heat-shock protein 70 (hsp70) gene and showed a higher sensitivity in the detection of gl ... | 2005 | 15929397 |
| identification of grapevines infected with divergent variants of grapevine virus a using variant-specific rt-pcr. | rt-pcrs, designed for the specific detection of molecular variants of grapevine virus a (gva), were applied to analysis of the virus from various grapevines and isolates recovered from these grapevines in nicotiana benthamiana. results of sscp, cloning and sequencing revealed that the combination of these rt-pcr techniques permits reliable and rapid identification of grapevines mixed-infected with divergent variants of gva. the results suggest that such grapevines are very common among gva-infec ... | 2003 | 12951225 |
| two classes of subgenomic rna of grapevine virus a produced by internal controller elements. | grapevine virus a (gva), a species of the recently established genus vitivirus, consists of an approximately 7.3-kb single-stranded rna genome of positive polarity, organized into five open reading frames (orfs). the virus, which is closely associated with the grapevine rugose wood disease complex, has been poorly investigated genetically. we explored the production of viral rnas in a gva-infected nicotiana benthamiana herbaceous host and characterized one nested set of three 5'-terminal sgrnas ... | 2003 | 12919748 |
| functional analysis of the grapevine virus a genome. | grapevine virus a (gva) carries five open reading frames (orfs). only the coat protein orf has been experimentally identified as such; the roles of some of the other orfs have been deduced by sequence homology to known genes (minafra et al., 1997). the construction of a full-length, infectious clone of gva has been previously reported. in an attempt to experimentally define the role of the various genes of gva, we utilized the infectious clone, inserted mutations in every orf, and studied the ef ... | 2003 | 12620796 |
| epitope mapping of grapevine virus a capsid protein. | previously characterized monoclonal antibodies (mabs) to grapevine virus a (gva) showed a differential reactivity against intact or partially destabilized virus particles [2]. in the present study, this differential reactivity was confirmed and several peptides reacting with a panel of four different antibodies were identified by the pepscan method of epitope mapping. oligopeptide sequences comprised between coat protein residues 61 (v) and 72 (t) were recognized by all the antibodies tested. on ... | 2002 | 11958461 |
| improved rna extraction and one-tube rt-pcr assay for simultaneous detection of control plant rna plus several viruses in plant extracts. | a procedure was developed for simultaneous detection of plant rna viruses and of plant rna, as a control. rt-pcr amplification with primers designed for the detection of the plant mrnas encoding malate dehydrogenase (mdh) and the large subunit of ribulose bisphosphate carboxylase oxygenase (rubiscol) was used for the development of a plant extraction procedure that consistently yields extracts that can be amplified. the control amplification was used successfully on extracts from cane, leaf and/ ... | 2000 | 11011079 |
| grapevine virus a: nucleotide sequence, genome organization, and relationship in the trichovirus genus. | the 5' terminal region of the genomic rna of grapevine virus a (gva), a tentative member of the trichovirus genus, encompassing 5466 nucleotides, was sequenced. evidence was obtained that the rna is capped. two putative open reading frames (orf) were identified: orf 1 that codes for a 194 kda polypeptide with conserved motifs of replication-related proteins of positive-strand rna viruses, and orf 2 that encodes a 19 kda polypeptide with no significant homology with protein sequences from databas ... | 1997 | 9125055 |
| the use of peroxidase anti-peroxidase (pap) complexes in the detection of plant viruses by elisa. | an elisa test system for detection of plant viruses in field samples is described, based on the unlabelled antibody method using a peroxidase-antiperoxidase (pap) complex. novel features of the system include the use of acid-treated naked bacteria as combined carrier-adjuvants for the production of rabbit antiviral antibodies, and the use of acid-treated chicken antibodies (igy) for antigen trapping in the elisa. systems for detection of potato virus y (pvy), potato leafroll virus (plrv), grapev ... | 1989 | 2685004 |
| production, characterization and use of monoclonal antibodies to grapevine virus a. | four stable hybridoma cell lines secreting monoclonal antibodies to grapevine closterovirus a (gva) were obtained by fusing spleen cells of immunized balb/c mice with mouse myeloma cell line sp2/0-ag 14. in elisa all mabs reacted with virus in leaf extracts from nicotiana benthamiana, glass-house-, field-, or in vitro-grown grapevines, or with cortical shavings from mature grape canes. in iem tests, only one of the mabs (pa3.f5) decorated virus particles on the entire surface. this mab was likel ... | 1992 | 1280942 |
| a multidisciplinary study on the effects of phloem-limited viruses on the agronomical performance and berry quality of vitis vinifera cv. nebbiolo. | viral infections are known to have a detrimental effect on grapevine yield and performance, but there is still a lack of knowledge about their effect on the quality and safety of end products. vines of vitis vinifera cv. nebbiolo clone 308, affected simultaneously by grapevine leafroll-associated virus 1 (glrav-1), grapevine virus a (gva), and rupestris stem pitting associated virus (rspav), were subjected to integrated analyses of agronomical performance, grape berry characteristics, instrument ... | 2011 | 21856458 |
| quantitation of grapevine leafroll associated virus-1 and -3, grapevine virus a, grapevine fanleaf virus and grapevine fleck virus in field-collected vitis vinifera l. 'nebbiolo' by real-time reverse transcription-pcr. | taqman one-step real-time qrt-pcr assays were developed for the quantitation of grapevine leafroll associated virus-1 and -3 (glrav-1 and -3), grapevine virus a (gva), grapevine fanleaf virus (gflv) and grapevine fleck virus (gfkv) in vitis vinifera l. virus load in the progenies of three 'nebbiolo' clones planted in two experimental vineyards in piemonte (northwestern italy), and carrying the viruses in different combinations, was evaluated. quantitation primers were designed on the rna-depende ... | 2010 | 21167205 |
| rugose wood-associated viruses do not appear to be involved in shiraz (syrah) decline in south africa. | the presence of rugose-wood-associated viruses of the genera foveavirus and vitivirus in the family betaflexiviridae was investigated in various clones of own-rooted and grafted vitis vinifera cv. shiraz that were affected, or not, by shiraz decline, and in rootstocks. rt nested-pcr amplification of double-stranded rna using degenerate primers for the simultaneous detection of foveaviruses and vitiviruses (dovas ci, katis ni in j virol meth 170:99-106, 2003), cloning of dna amplicons, sscp analy ... | 2010 | 20549265 |
| analysis of multiple virus-infected grapevine plant reveals persistence but uneven virus distribution. | ln33 grapevine plants were artificially inoculated with budwoods originating from a field-cultivated traminer grapevine which was naturally infected with grapevine leafroll-associated virus 1 (glrav-1), grapevine virus a (gva), grapevine virus b (gvb), rupestris stem pitting-associated virus (rspav), and an unclassified tymovirus. four years after inoculation, a comparison of the cane weights between healthy and infected grapevines did not show any significant difference. corky bark symptoms or ... | 2009 | 19941393 |
| a diagnostic oligonucleotide microarray for simultaneous detection of grapevine viruses. | at least 58 viruses have been reported to infect grapevines causing economic damage globally. conventional detection strategies based on serological assays, biological indexing and rt-pcr targeting one or few viruses in each assay are widely used. grapevines are prone to contain mixed infections of several viruses, making the use of these techniques time-consuming. a 70-mer oligonucleotide microarray able to detect simultaneously a broad spectrum of known viruses as well as new viruses by cross- ... | 2010 | 19914293 |
| expressing a whitefly groel protein in nicotiana benthamiana plants confers tolerance to tomato yellow leaf curl virus and cucumber mosaic virus, but not to grapevine virus a or tobacco mosaic virus. | transgenesis offers many ways to obtain virus-resistant plants. however, in most cases resistance is against a single virus or viral strain. we have taken a novel approach based on the ability of a whitefly endosymbiotic groel to bind viruses belonging to several genera, in vivo and in vitro. we have expressed the groel gene in nicotiana benthamiana plants, postulating that upon virus inoculation, groel will bind to virions, thereby interfering with pathogenesis. the transgenic plants were inocu ... | 2009 | 19184338 |
| cloning and characterization of vigg, a novel virus-induced grapevine protein, correlated with fruit quality. | we report here the identification and characterization of vigg, a novel virus-induced grapevine protein. analysis of vigg expression in grapevine demonstrated that vigg was constitutively expressed in leaves and stems in virus-infected grapevine, and that vigg expression was induced by grapevine virus a (gva) infection, but not by infection with other viruses. the virus-induced expression profile of vigg was supported by the finding that virus-free meristem cultures prepared from virus-infected ... | 2009 | 19138527 |
| comparative detection of a large population of grapevine viruses by taqman(®) rt-qpcr and elisa. | grapevine (vitis spp.) can be infected by numerous viruses that are often widespread and of great economic importance. reliable detection methods are necessary for sanitary selection which is the only way to partly control grapevine virus diseases. biological indexing and elisa are currently the standard methods for screening propagation material, and pcr-methods are becoming increasingly popular. due to the diversity of virus isolates, it is essential to verify that the tests allow the detectio ... | 2017 | 27923589 |
| multiplex rt-pcr method for the simultaneous detection of nine grapevine viruses. | viral diseases are a serious pathological problem for grapevines, and in recent years the need for increasingly specific and rapid diagnostic methods for the selection of propagation materials has grown. arabis mosaic virus, grapevine fanleaf virus, grapevine virus a, grapevine virus b, grapevine rupestris stem pitting-associated virus, grapevine fleck virus, and grapevine leafroll-associated viruses 1, 2, and 3 are nine of the most widespread viruses that naturally infect grapevines. a multiple ... | 2015 | 25287494 |
| evidence of grapevine leafroll associated virus-1-3, grapevine fleck virus and grapevine virus b occurring in himachal pradesh, india. | during a survey conducted in the grapevine orchards of himachal pradesh, variety of symptoms ranging from leaf yellowing, vein greening, reduced leaf size, downward rolling/cup shaped leaves to reduced fruit bearing were observed. symptomatic leaf samples were collected and analyzed by serological (das-elisa) and molecular methods (rt-pcr, pcr) for viruses and phytoplasma known worldwide on grapevine. das-elisa was used for detection of grapevine leafroll associated virus 1, 2 and 3 (glrav-1, 2 ... | 2013 | 24426260 |
| transmission of grapevine virus a and grapevine leafroll-associated virus 1 and 3 by heliococcus bohemicus (hemiptera: pseudococcidae) nymphs from plants with mixed infections. | mealybugs (hemiptera: pseudococcidae) represent a serious threat for viticulture as vectors of phloem-restricted viruses associated with the grapevine rugose wood and leafroll diseases. heliococcus bohemicus (šulc) is known to be involved in the spread of these two viral diseases, being a vector of the grapevine virus a (gva) and the grapevine leafroll-associated virus 1 and 3 (glrav-1 and glrav-3). this study investigated the acquisition and transmission efficiency of h. bohemicus fed on mixed- ... | 2016 | 27329628 |
| transmission of six ampeloviruses and two vitiviruses to grapevine by phenacoccus aceris. | grapevine leafroll disease is caused by grapevine leafroll-associated viruses (glravs). these viruses are common in vineyards worldwide and often associated with vitiviruses that are involved in the rugose wood complex of grapevine. ten mealybug species are known as vectors of one or several of these grapevine viruses, including the apple mealybug phenacoccus aceris which is widespread in holarctic regions and able to transmit grapevine leafroll-associated virus-1 and -3 (glrav-1 and -3). our ai ... | 2012 | 22439861 |
| zno films formed by atomic layer deposition as an optical biosensor platform for the detection of grapevine virus a-type proteins. | novel sensitive optical biosensor for determination of grapevine virus a-type (gva) proteins (gva-antigens) has been designed. this biosensor was based on thin films of zinc oxide (zno) deposited by atomic layer deposition (ald). the zno-based films have demonstrated favorable surface-structural properties for the direct immobilization of antibodies against gva-antigens in order to form a biosensitive layer sensitive to gva-antigens. the immobilization was confirmed by intensity changes in the m ... | 2017 | 28034507 |
| brief report of the construction of infectious dna clones of south african genetic variants of grapevine virus a and grapevine virus b. | recent research results strongly suggest that certain genetic variants of grapevine virus a (gva) and grapevine virus b (gvb), two members of the vitivirus genus of the family betaflexiviridae, are the cause of shiraz disease and corky bark disease of grapevines in south africa, respectively. to investigate this hypothesis, work was undertaken to construct dna clones of these viruses. | 2015 | 26640751 |
| preparation and characterization of monomodal grapevine virus a capsid protein. | grapevine virus a (gva), a flexible filament of approximately 800 nm in length is composed of capsid subunits that spontaneously assembles around a positive sense genomic rna. in addition to encapsidation, plant viruses capsid proteins (cps) participate in other processes throughout infection and gva cp is involved in cell-to-cell translocation of the virus. a protocol was developed to obtain low-molecular weight gva-cp that is not prone to aggregation and spontaneous assembly and this was chara ... | 2015 | 26112976 |
| complete genome sequence of a natural mutant of grapevine virus a (gva). | a new genetic variant of grapevine virus a (gva) of phylogenetic group i was identified during comparative analysis of the viruses infecting two sibling grapevines cv. shiraz. the grapevines were propagated from a single mother plant. one of them become infected with shiraz disease (sd), which is highly destructive on noble grapevine cultivars shiraz and merlot in south africa. the new variant was not associated with sd, as it was present in both sd-affected and sd-free plants. however, unlike i ... | 2014 | 24756347 |
| genetic diversity of grapevine virus a in washington and california vineyards. | grapevine virus a (gva; genus vitivirus, family betaflexiviridae) has been implicated with the kober stem grooving disorder of the rugose wood disease complex. in this study, 26 isolates of gva recovered from wine grape (vitis vinifera) cultivars from california and washington were analyzed for their genetic diversity. an analysis of a portion of the rna-dependent rna polymerase (rdrp) and complete coat protein (cp) sequences revealed intra- and inter-isolate sequence diversity. our results indi ... | 2014 | 24168043 |
| development and validation of a multiplex quantitative pcr assay for the rapid detection of grapevine virus a, b and d. | a single real-time multiplex quantitative pcr (qpcr) assay for the simultaneous detection of grapevine virus a, b and d (gva, gvb and gvd) was developed, using three different fluorescently labeled minor groove binding probes. this multiplex rt-qpcr was compared to singleplex rt-qpcr designed specifically for each virus and a conventional multiplex rt-pcr. the capacity of the multiplex rt-qpcr assay in detecting the three vitiviruses in mixed infections from a range of virus concentrations in th ... | 2013 | 23973785 |
| detection and characterisation of two novel vitiviruses infecting actinidia. | two co-infecting novel vitiviruses from actinidia chinensis were identified from mechanically inoculated nicotiana occidentalis. both virus genomes were sequenced and share 64% nucleotide identity. their overall structure is typical of vitiviruses, with five open reading frames (orfs) and a polyadenylated 3' end. open reading frame 4 (orf4) encodes the coat protein, the most conserved gene of the vitiviruses, in which they share 75% amino acid identity, 61-68% with grapevine virus b, 55-59% with ... | 2012 | 22274622 |