Characterization of a new potyvirus isolated from peanut (Arachis hypogaea)

During a survey of viruses of peanuts in South Africa a mechanically transmissible virus was isolated from a plant exhibiting chlorotic ringspots and blotches on the leaves. Typical potyvirus-like flexuous particles were detected by electron microscope examination. Pinwheel-shaped and laminated inclusions in ultrathin sections, reaction with a monoclonal antibody directed to a potyvirus common epitope, a single 33 kDa coat protein and aphid transmission using Myzus persicae all confirmed that the virus was a subdivision II member of the Potyviridae. Host range studies suggested that the virus was none of the previously reported potyviruses of peanuts or of subdivision II potyviruses. The serological relationships of the virus were studied using a range of 17 antisera to potyviruses in ELISA and immunosorbent electron microscopy (ISEM). The isolate reacted weakly with antisera to plum pox virus and bean yellow mosaic virus in ISEM only. Nucleotide sequence of a 624 bp DNA product was obtained following immuno-capture with a potyvirus common epitope antiserum, cDNA synthesis and PCR amplification with potyvirus specific primers which amplify the 3' untranslated region and a part of the coat protein gene. The sequence was only distantly related to a number of potyviruses, whether amino acid or nucleotide sequences were used for comparisons. It is proposed that the virus be named peanut chlorotic blotch virus and be accepted as a new member of the genus Potyvirus in the family Potyviridae.     

Serotypic variation in turnip mosaic virus

A panel of 30 monoclonal antibodies (MAbs) was produced against four isolates of turnip mosaic virus (TuMV). The panel was tested in plate-trapped antigen ELISA tests against 41 TuMV isolates (with different host and geographical origins and of differing pathotypes). The antibodies were also tested against four other potyviruses (bean common mosaic virus, bean common mosaic necrosis virus, lettuce mosaic virus and zucchini yellow mosaic virus). The reactions were assessed quantitatively (using multivariate analysis) and qualitatively (using the standard deviation obtained against healthy leaf material). The MAbs recognized 16–17 TuMV epitopes that were not present in the other potyviruses and a further two potyvirus epitopes. The isolates were grouped into three serotypes. Only one isolate did not fit this grouping. The classification of seven isolates in coat protein amino acid sequence homology groups correlated with serotypes. There was no correlation between serotype and pathotype, or between reactions to individual MAbs and single lines. There was therefore no evidence that the epitopes recognized by the MAbs are elicitors for the resistance genes present in the Brassica napus lines. However, the sensitivity and specificity of the MAbs will be useful for both routine detection of TuMV and fundamental studies on plant–virus interactions.     

Characterization of a strain of clover yellow vein potyvirus infecting borage (Borago officinalis L.) in Spain

A disease of borage ( Borago officinalis ) in Spain, characterized by severe mosaic and deformation of the leaves, was shown to be caused by a potyvirus. The borage-infecting potyvirus was characterized biologically by the symptoms induced in 23 indicator species and was shown to be transmitted experimentally by the aphid Myzus persicae in a non-persistent manner. In order to classify the borage-infecting potyvirus we have cloned and sequenced the entire coat protein gene and 3' non-coding region of the viral RNA. By comparing this nucleotide sequence with those of other members of the Potyviridae , we can identify the Spanish borage-infecting potyvirus as an isolate of clover yellow vein virus (CYVV), a virus so far only known to cause important diseases in forage legumes. This is the first record of CYVV in Spain and of CYVV infecting a natural host of the Boraginaceae.     

Characterization of a potyvirus from eggplant (Solanum melongena) as a strain of potato virus Y by N-terminal serology and sequence relationships

A potyvirus (eggplant mottle virus, EMoV) causing mosaic mottling in eggplant ( Solanum melongena ) was characterized on the basis of biological, serological and partial nucleotide sequence properties. EMoV infected Chenopodium amaranticolor and members of the Solanaceae. Polyclonal antiserum against EMoV showed antigenic relationship with henbane mosaic potyvirus (HMV) and potato Y potyvirus (PVY). Virus-specific antibodies directed to the N-terminal region of EMoV cross-reacted only with PVY. Determination and comparison of nucleotide sequence of the coat protein (CP) and the 3'-untranslated region (UTR) of EMoV with other potyviruses showed that the level of homology was highest with PVY isolates. Comparative sequence analyses of the CP amino acid and 3'-UTR sequences with distinct PVY isolates placed EMoV within the PVY^O subgroup.     

Pfaffia mosaic virus: a new potyvirus found infecting Pfaffia glomerata in Brazil

In Brazil plants of Pfaffia glomerata with mosaic symptoms were found to be infected with a previously undescribed potyvirus, Pfaffia mosaic virus (PfMV). Virus particles were long and flexuous, c.  10 × 700–800 nm, and cylindrical inclusions typical of potyviruses were present in cells of infected tissue. Partial host-range studies revealed that in addition to P. glomerata , PfMV infected only Chenopodium amaranticolor and Chenopodium quinoa . It was efficiently transmitted by the aphids Aphis gossypii and Myzus persicae . Polyclonal antiserum produced against the PfMV coat protein (CP) reacted with Potato virus Y (PVY), but not with four other potyviruses in PTA-ELISA. The similarity of the nucleotide sequence of the PfMV coat-protein gene ( CP ) varied from 7 to 76% when compared with other members of the family Potyviridae . Similarity of the 3' NTR sequence varied from 4 to 23%. In both cases the highest similarity was with PVY. These data indicate that PfMV is a new species in the genus Potyvirus .     

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'). Because WSMV shares with ryegrass mosaic virus (RGMV) the biological property of transmission by eriophyid mites, WSMV has been assigned to the genus Rymovirus, of which RGMV is the type species. Phylogenetic analyses were conducted with complete polyprotein or NIb protein sequences of 11 members of the family Potyviridae, including viruses of monocots or dicots and viruses transmitted by aphids, whiteflies, and mites. WSMV and the monocot-infecting, mite-transmitted brome streak mosaic virus (BrSMV) are sister taxa and share a most recent common ancestor with the whitefly-transmitted sweet potato mild mottle virus, the type species of the proposed genus "Ipomovirus." In contrast, RGMV shares a most recent common ancestor with aphid-transmitted species of the genus Potyvirus. These results indicate that WSMV and BrSMV should be classified within a new genus of the family Potyviridae and should not be considered species of the genus Rymovirus.     

New potyvirus isolated from <Emphasis Type="Italic">Cryptotaenia japonica</Emphasis>

 A potyvirus, for which the name Japanese hornwort mosaic virus (JHMV) is proposed, was isolated from Japanese hornwort plants (Cryptotaenia japonica) with mosaic disease symptoms. The virus was used to inoculate mechanically 34 plants belonging to 33 species of 10 families. Of these species seven from two families were infected. Faint chlorotic spots appeared on the inoculated leaves of Chenopodium quinoa and C. amaranticolor, but no systemic infection occurred in these plants. JHMV systemically infected only Umbelliferae plants; they did not infect 26 other species in eight families. JHMV was transmitted in a nonpersistent manner by aphids (Myzus persicae). The virus was a flexuous rod-shaped particle about 750 nm in length. Sequencing the nucleotides in the 3′ terminal region of JHMV revealed that the coat protein contains 280 amino acids with a molecular mass of 32.2 kDa. The nucleotide sequence of the coat protein of JHMV had the highest similarity with that of Zantedeschia mosaic virus (83.3%) compared to those of other potyviruses (57.0%–64.9%). An antiserum against JHMV reacted strongly with JHMV and weakly with Potato virus Y. These results indicate that JHMV is a new potyvirus. Received: September 9, 2002 / Accepted: November 7, 2002 RID="*" ID="*" The nucleotide sequence determined in this work appears in the DDBJ/EMBL/GenBank nucleotide sequence databases with the accession number AB081518     

The Complete Nucleotide Sequence and Biotype Variability of Papaya leaf distortion mosaic virus

ABSTRACT The complete nucleotide sequence of the genome of Papaya leaf distortion mosaic virus (PLDMV) was determined. The viral RNA genome of strain LDM (leaf distortion mosaic) comprised 10,153 nucleotides, excluding the poly(A) tail, and contained one long open reading frame encoding a polyprotein of 3,269 amino acids (molecular weight 373,347). The polyprotein contained nine putative proteolytic cleavage sites and some motifs conserved in other potyviral polyproteins with 44 to 50% identities, indicating that PLDMV is a distinct species in the genus Potyvirus. Like the W biotype of Papaya ringspot virus (PRSV), the non-papaya-infecting biotype of PLDMV (PLDMV-C) was found in plants of the family Cucurbitaceae. The coat protein (CP) sequence of PLDMV-C in naturally infected-Trichosanthes bracteata was compared with those of three strains of the P biotype (PLDMV-P), LDM and two additional strains M (mosaic) and YM (yellow mosaic), which are biologically different from each other. The CP sequences of three strains of PLDMV-P share high identities of 95 to 97%, while they share lower identities of 88 to 89% with that of PLDMV-C. Significant changes in hydrophobicity and a deletion of two amino acids at the N-terminal region of the CP of PLDMV-C were observed. The finding of two biotypes of PLDMV implies the possibility that the papaya-infecting biotype evolved from the cucurbitaceae-infecting potyvirus, as has been previously suggested for PRSV. In addition, a similar evolutionary event acquiring infectivity to papaya may arise frequently in viruses in the family Cucurbitaceae.     

A potyvirus isolated from Senna occidentalis

A potyvirus causing severe mosaic symptoms was isolated from Senna occidentalis (syn. Cassia occidentalis ) in the Yemen Republic and Ethiopia. It was transmitted mechanically and by Myzus persicae in a non-persistent manner. The flexuous, rod-shaped particles had a mean length of 830 nm, and pinwheels and scrolls were observed by electron microscopy of thin sections of infected Nicotiana clevelandii leaves. Its host range was narrow with only a few legume species, Nicotiana clevelandii and N. benthamiana susceptible to experimental infection. This virus was purified from N. clevelandii and the coat protein had a molecular mass of 34-5 kDa. It reacted positively in ELISA with monoclonal antibody 197 that is specific for potyviruses, but was not decorated by antibodies to any other potyvirus tested when examined by electron microscopy. The virus has been tentatively named cassia severe mosaic potyvirus.     

Identification and characterization of a potyvirus causing chlorotic spots on <Emphasis Type="Italic">Phalaenopsis</Emphasis> orchids

A putative virus-induced disease showing chlorotic spots on leaves of Phalaenopsis orchids was observed in central Taiwan. A virus culture, phalaenopsis isolate 7-2, was isolated from a diseased Phalaenopsis orchid and established in Chenopodium quinoa and Nicotiana benthamiana. The virus reacted with the monoclonal antibody (POTY) against the potyvirus group. Potyvirus-like long flexuous filament particles around 12–15 × 750–800 nm were observed in the crude sap and purified virus preparations, and pinwheel inclusion bodies were observed in the infected cells. The conserved region of the viral RNA was amplified using the degenerate primers for the potyviruses and sequence analysis of the virus isolate 7-2 showed 56.6–63.1% nucleotide and 44.8–65.1% amino acid identities with those of Bean yellow mosaic virus (BYMV), Beet mosaic virus (BtMV), Turnip mosaic virus (TuMV) and Bean common mosaic virus (BCMV). The coat protein (CP) gene of isolate 7-2 was amplified, sequenced and found to have 280 amino acids. A homology search in GenBank indicated that the virus is a potyvirus but no highly homologous sequence was found. The virus was designated as Phalaenopsis chlorotic spot virus (PhCSV) in early 2006. Subsequently, a potyvirus, named Basella rugose mosaic virus isolated from malabar spinach was reported in December 2006. It was found to share 96.8% amino acid identity with the CP of PhCSV. Back-inoculation with the isolated virus was conducted to confirm that PhCSV is the causal agent of chlorotic spot disease of Phalaenopsis orchids in Taiwan. This is the first report of a potyvirus causing a disease on Phalaenopsis orchids.     

Serological relationships between the cylindrical inclusion proteins of potyviruses

ABSTRACT Antisera to the cytoplasmic inclusion proteins (CIPs) of bean yellow mosaic (BYMV), clover yellow vein (ClYVV), turnip mosaic (TuMV), sweet potato feathery mottle (SPFMV), and maize dwarf mosaic (MDMV) potyviruses were used to examine the relationships between the CIPs of 18 potyviruses. The antisera to CIPs of BYMV, ClYVV, TuMV, and SPFMV cross-reacted to most or all of the purified CIPs tested in western blot assays. The MDMV CIP antiserum reacted significantly only to the MDMV and sorghum mosaic virus CIPs. Reactivity of antisera to CIPs of dicot-infecting viruses was generally higher with CIPs of other dicot-infecting than with monocot-infecting potyvirus CIPs. Analysis of amino acid sequences of the CI genes of 11 well-characterized potyviruses suggested that epitopes specific for individual potyviruses are primarily in the C-terminal domains of the CIP, whereas epitopes shared among different viruses are clustered in the N-terminal domains. The most highly conserved predicted epitope overlaps the nucleotide binding motif of the N-terminal helicase domain of the CIP. Antibodies to this domain will probably be present in antisera to any potyvirus CIP and contribute to the cross-reactivity observed. Differences in the C-terminal domains may correlate with interactions between the CIP and coat protein necessary for replication and movement.     

Characterisation of a maize-infecting potyvirus from Spain

In order to characterise and classify an unknown maize-infecting potyvirus isolated from fields in northeast Spain, the entire coat protein gene and the C-terminal twothirds of the large nuclear inclusion protein (NIb) gene were cloned and sequenced. Protein sequencing enabled the cleavage site between the two proteins to be deduced and also revealed that on storage the viral coat protein undergoes a specific degradation in which the N-terminal 39 amino acids are removed. Comparison of the nucleotide sequence of the 3 non-coding region of the viral RNA and the predicted amino acid sequence of the coat protein with the equivalent regions of other members of the potyvirus group revealed that the Spanish virus is closely related to maize dwarf mosaic virus strain A.     

Taxonomy of Wisteria vein mosaic virus and extensions to its host range and geographical distribution

Wisteria mosaic, a serious disease of Wisteria spp. in horticultural production in many parts of the world, is caused by a virus, Wisteria vein mosaic virus (WVMV). This paper reports the presence of the virus in a new host, Wisteria venusta , and a new geographical distribution, New South Wales, Australia. A partial sequence (1329 nucleotides) of this isolate of WVMV was obtained, which represents the first available sequence data for the virus. Alignment of the nucleotide and predicted amino acid sequences with those of members of the Potyviridae showed closest identity with viruses of the Potyvirus genus. The predicted amino acid sequence has one open reading frame, open at the 5' end, corresponding to part of the nuclear inclusion b protein and the capsid protein, followed by a 251-nucleotide untranslated region and a polyadenylated tail at the 3' end.     

A potyvirus isolated from solanaceous hosts

A potyvirus was isolated from Datura stramonium, Lycopersicon esculentum (tomato) and Solanum nigrum in the Yemen. It was transmitted mechanically and by Myzus persicae in a non-persistent manner. Its flexuous rod-shaped particles had a mean length of 719 nm and some of its pinwheel inclusion bodies in infected Nicotiana clevelandii leaves were unusual in that they were dichotomously branched. The virus infected various solanaceous species, but the symptoms it induced were distinct from those of pepper veinal mottle (PVMV) and potato Y viruses. Its particles were purified from N. glutinosa and their coat protein had an atypically high molecular mass a potyvirus of 41·5 kDa. They showed a distant serological relationship to those of PVMV and potato virus V in ISEM decoration tests, but did not react with antisera to particles of any other potyvirus tested. The virus has been tentatively named tomato mild mottle virus.     

Molecular characterization of the Cassava brown streak virus coat protein

A partial sequence of 1114 nucleotides of a virus from cassava brown streak diseased (CBSD) material was obtained. Alignment of the predicted amino acid sequence with those of other members of the Potyviridae showed closest identity with the coat protein of Sweet potato mild mottle virus (genus Ipomovirus ). The predicted amino acid sequence has one open reading frame with a 3' untranslated region of 144 nucleotides and a poly(A) tail. The expressed protein was shown to cross-react with an antiserum raised previously to a virus isolated from CBSD material. Evidence presented suggests that CBSD is caused by Cassava brown streak virus , a tentative member of the genus Ipomovirus , as this virus is consistently found associated with CBSD.     

我国12省市玉米矮花叶病病原鉴定及病毒致病性测定

 利用甘蔗花叶病毒(Sugarcane mosaic virus,SCMV)单克隆抗体细胞株2B5腹水和SCMV、玉米矮花叶病毒(Maize dwarf mosaic virus,MDMV)、高粱花叶病毒(Sorghum mosaic virus,SrMV)和约翰逊草花叶病毒(Johnsongrass mosaic virus,JGMV)的特异性引物对我国浙江、江苏、上海、山东、河南、河北、北京、山西、陕西、甘肃、四川、云南12省市15个地点的176株玉米矮花叶病病样分别进行了间接ELISA和免疫捕获反转录PCR (IC-RT-PCR)检测,结果表明这些病样均含有SCMV,而无MDMV、SrMV或JGMV存在,表明上述12省市的玉米矮花叶病病原为SCMV。进一步对甘肃(GS)、四川(SC)、云南(YN)3个SCMV分离物的近全长CP基因进行了序列测定,并测定了浙江分离物(ZJ)和甘肃分离物(GS)在13个玉米品种上的致病性。     

Characterization of a novel potyvirus isolated from maize in Israel

A potyvirus (proposed name of Zea mosaic virus [ZeMV]) isolated from maize in Israel was analyzed by serology, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of capsid proteins, symptomatology, and sequencing. Parts of the nuclear inclusion b, coat protein, and 3' regions were sequenced; the amino acid sequence of ZeMV capsid was determined by time-of-flight mass spectrometry (TOFMS). The results of these analyses were compared with those of similar analyses of the following potyviruses: Maize dwarf mosaic virus (MDMV), Sugarcane mosaic virus strain MDB (SCMV-MDB), Johnsongrass mosaic virus(JGMV), Sorghum mosaic virus (SrMV), and an isolate of MDMV from Israel. Indirect enzyme-linked immunosorbent assay using ZeMV antiserum detected only ZeMV, and reciprocal tests using MDMV, JGMV, or SrMV antisera failed to detect ZeMV. ZeMV cross-reacted weakly when SCMV-MDB antiserum was used. The mass of ZeMV capsid was determined to be 36,810 Da by SDS-PAGE and 34,216 Da by TOFMS. The ZeMV systemically infected johnsongrass (Sorghum halepense), but did not infect oat (Avena sativa), pearl millet (Pennisetum glaucum), barley (Hordeum vulgare), or rye (Secale cereale). Necrosis was caused in 19 sorghum lines by SrMV, in 15 by ZeMV, in 14 by MDMV, and in 5 by JGMV and SCMV-MDB. The nucleic acid and amino acid sequences of ZeMV clearly showed that it is not a strain of JGMV, MDMV, SCMV, or SrMV.