| possible members of the potyvirus group transmitted by mites or whiteflies share epitopes with aphid-transmitted definitive members of the group. | there are at least ten viruses identified in the literature that resemble definitive potyviruses in having flexuous filamentous particles and inducing the formation of "pinwheel" cytoplasmic inclusions in infected cells but that are transmitted by eriophyid mites, whiteflies or soil fungi and not by aphids, the vectors of the definitive potyviruses. the taxonomic status of these viruses is uncertain at present. using a broadly cross-reactive antiserum raised against the dissociated coat protein ... | 1989 | 2473719 |
| cytological and molecular evidence that the whitefly-transmitted cucumber vein yellowing virus is a tentative member of the family potyviridae. | cucumber vein yellowing virus (cvyv) is widespread in cucurbits in the middle east. cvyv has filamentous particles and is transmitted by bemisia tabaci by the semi-persistent mode. it has not yet been assigned to a specific genus or family. ultramicroscopic observations revealed numerous cylindrical cytoplasmic inclusions in melon and cucumber cells infected by cvyv isolates from israel and jordan. depending on the section orientation, the inclusions appeared as pinwheels or as bundles. in addit ... | 2000 | 10950987 |
| sequence variability within the 3'-proximal part of the sweet potato mild mottle virus genome. | sweet potato mild mottle virus (spmmv) is the type member of the genus ipomovirus (family potyviridae) and is only known to occur in east africa. in uganda, spmmv is the third most prevalent virus infecting sweet potato. the sequence variability of spmmv was studied by cloning and sequencing a 1.8-kb fragment representing the 3'-end of the genome of eight spmmv isolates collected from different districts of uganda. sequence comparisons indicated 85.9-99.9% nucleotide sequence identity and 92.8-1 ... | 2003 | 12607100 |
| whitefly transmission of sweet potato viruses. | three genera of plant viruses, begomovirus (geminiviridae), crinivirus (closteroviridae) and ipomovirus (potyviridae), contain members that infect sweet potato (ipomoea batatas) and are transmitted by whiteflies. the begomoviruses, sweet potato leaf curl virus (splcv) and ipomoea leaf curl virus (ilcv), and the ipomovirus sweet potato mild mottle virus are transmitted by bemisia tabaci, the sweet potato whitefly. the crinivirus, sweet potato chlorotic stunt virus (spcsv), is transmitted by b. ta ... | 2004 | 15036843 |
| presence of p1b and absence of hc-pro in squash vein yellowing virus suggests a general feature of the genus ipomovirus in the family potyviridae. | the genus ipomovirus is one of six currently recognized genera in the family potyviridae. the complete nucleotide sequence of squash vein yellowing virus (sqvyv), a putative ipomovirus recently described in florida, has been determined. the 9836 nt sqvyv genomic rna [excluding the poly(a) tail] has one large open reading frame encoding a single polyprotein of 3172 amino acids, typical of the genome organization for most members in the family potyviridae. the 10 mature proteins predicted to be de ... | 2008 | 18455828 |
| phylogenetic relationships within the family potyviridae: wheat streak mosaic virus and brome streak mosaic virus are not members of the genus rymovirus. | abstract the complete nucleotide sequence of wheat streak mosaic virus (wsmv) has been determined based on complementary dna clones derived from the 9,384-nucleotide (nt) rna of the virus. the genome of wsmv has a 130-nt 5' leader and 149-nt 3'-untranslated region and is polyadenylated at the 3' end. wsmv rna encodes a single polyprotein of 3,035 amino acid residues and has a deduced genome organization typical for a member of the family potyviridae (5'-p1/hc-pro/p3/6k1/ci/6k2/vpg-nia/nib/cp-3') ... | 1998 | 18944883 |
| unravelling the genetic diversity of the three main viruses involved in sweet potato virus disease (spvd), and its practical implications. | summary sweetpotato (ipomoea batatas) is a widely grown food crop, in which the most important diseases are caused by viruses. genetic variability of three widely distributed sweetpotato viruses was analysed using data from 46 isolates of sweet potato feathery mottle virus (spfmv), 16 isolates of sweet potato mild mottle virus (spmmv) and 25 isolates of sweet potato chlorotic stunt virus (spcsv), of which 19, seven and six isolates, respectively, are newly characterized. division of spfmv into f ... | 2005 | 20565651 |
| overview and analysis of the polyprotein cleavage sites in the family potyviridae. | summary the genomes of plant viruses in the family potyviridae encode large polyproteins that are cut by virus-encoded proteases into ten mature proteins. three different types of protease have been identified, each of which cuts at sites with a distinctive sequence pattern. the experimental evidence for this specificity is reviewed and the cleavage site patterns are compiled for all sequenced species within the family. seven of the nine cleavage sites in each species are cut by the viral nia-pr ... | 2005 | 20565672 |
| analysis of complete genomic sequences of isolates of the sweet potato feathery mottle virus strains c and ea: molecular evidence for two distinct potyvirus species and two p1 protein domains. | the complete nucleotide sequence of the isolate c1 of sweet potato feathery mottle virus (spfmv) strain c and the 5' region of several other strains were determined and analyzed together with the sequences of isolates representing the ea, rc and o strains. this provided molecular evidence for the reclassification of spfmv strains into two species and the occurrence of a complex recombinant isolate. analysis also revealed a hypervariable domain in the p1 protein, which separates an n-terminal reg ... | 2010 | 20882307 |
| Low genetic diversity of Squash vein yellowing virus in wild and cultivated cucurbits in the U.S. suggests a recent introduction. | Squash vein yellowing virus (SqVYV) isolates were collected from cultivated and weedy cucurbits representing major hosts and locations in the U.S. and analyzed to better understand the diversity and population structure. No differences in symptoms were observed in field-collected isolate source plants or subsequently inoculated greenhouse plants, and the complete genome of an SqVYV isolate from a wild cucurbit host (smellmelon, Cucumis melo var. dudaim) was highly similar (99.4% nucleotide ident ... | 2011 | 22142477 |
| development of transgenic sweet potato with multiple virus resistance in south africa (sa). | multiple infections of sweet potato feathery mottle virus (spfmv), sweet potato chlorotic stunt virus (spcsv), sweet potato virus g (spvg) and sweet potato mild mottle virus (spmmv) cause a devastating synergistic disease complex of sweet potato (ipomoea batatas lam.) in kwazulu-natal, south africa. in order to address the problem of multiple virus infections and synergism, this study aimed to develop transgenic sweet potato (cv. blesbok) plants with broad virus resistance. coat protein gene seg ... | 2014 | 24158330 |
| mixed infections of four viruses, the incidence and phylogenetic relationships of sweet potato chlorotic fleck virus (betaflexiviridae) isolates in wild species and sweetpotatoes in uganda and evidence of distinct isolates in east africa. | viruses infecting wild flora may have a significant negative impact on nearby crops, and vice-versa. only limited information is available on wild species able to host economically important viruses that infect sweetpotatoes (ipomoea batatas). in this study, sweet potato chlorotic fleck virus (spcfv; carlavirus, betaflexiviridae) and sweet potato chlorotic stunt virus (spcsv; crinivirus, closteroviridae) were surveyed in wild plants of family convolvulaceae (genera astripomoea, ipomoea, hewittia ... | 2016 | 28005969 |
| switching on rna silencing suppressor activity by restoring argonaute binding to a viral protein. | we found that sweet potato feathery mottle virus (spfmv) p1, a close homologue of sweet potato mild mottle virus p1, did not have any silencing suppressor activity. remodeling the argonaute (ago) binding domain of spfmv p1 by the introduction of two additional wg/gw motifs converted it to a silencing suppressor with ago binding capacity. to our knowledge, this is the first instance of the transformation of a viral protein of unknown function to a functional silencing suppressor. | 2012 | 22623784 |
| eggplant mild leaf mottle virus (emlmv), a new putative member of the genus ipomovirus that harbors an hc-pro gene. | since 2003, a new viral disease of eggplant (solanum melongena l.) has been spreading in fields in the jordan and arava valleys, israel. the symptoms of this disease include mild leaf mottling and varying degrees of fruit distortion. this disease can be transmitted by mechanical sap inoculation, as well as by the whitefly bemisia tabaci (homoptera, aleyrodidae) and has been tentatively named eggplant mild leaf mottle virus (emlmv). our study aimed to determine the complete sequence and genome or ... | 2012 | 22086504 |
| analysis of the tomato mild mottle virus genome indicates that it is the most divergent member of the genus ipomovirus (family potyviridae). | the complete genome of a tomato mild mottle virus (tommv) isolate was analysed, and some biological features were characterized. the ssrna genome of tommv from ethiopia encompasses 9283 nucleotides (excluding the 3' poly(a) tail) and encodes a polyprotein of 3011 amino acids. phylogenetic and pairwise comparisons with other members of the family potyviridae revealed that tommv is the most divergent member of the genus ipomovirus, with a genome organization similar to that of members of the speci ... | 2012 | 22080188 |
| viral protein inhibits risc activity by argonaute binding through conserved wg/gw motifs. | rna silencing is an evolutionarily conserved sequence-specific gene-inactivation system that also functions as an antiviral mechanism in higher plants and insects. to overcome antiviral rna silencing, viruses express silencing-suppressor proteins. these viral proteins can target one or more key points in the silencing machinery. here we show that in sweet potato mild mottle virus (spmmv, type member of the ipomovirus genus, family potyviridae), the role of silencing suppressor is played by the p ... | 2010 | 20657820 |
| recombination and selection pressure in the ipomovirus sweet potato mild mottle virus (potyviridae) in wild species and cultivated sweetpotato in the centre of evolution in east africa. | sweet potato mild mottle virus (spmmv) is the type member of the genus ipomovirus (family potyviridae). spmmv occurs in cultivated sweetpotatoes (ipomoea batatas lam.; convolvulaceae) in east africa, but its natural wild hosts are unknown. in this study, spmmv was detected in 283 (9.8 %) of the 2864 wild plants (family convolvulaceae) sampled from different agro-ecological zones of uganda. the infected plants belonged to 21 species that were previously not known to be natural hosts of spmmv. the ... | 2010 | 19923261 |
| a viral suppressor of rna silencing inhibits argonaute 1 function by precluding target rna binding to pre-assembled risc. | in most eukaryotes, rna silencing is an adaptive immune system regulating key biological processes including antiviral defense. to evade this response, viruses of plants, worms and insects have evolved viral suppressors of rna silencing proteins (vsrs). various vsrs, such as p1 from sweet potato mild mottle virus (spmmv), inhibit the activity of rna-induced silencing complexes (riscs) including an argonaute (ago) protein loaded with a small rna. however, the specific mechanisms explaining this c ... | 2017 | 28499009 |