The Nucleotide Sequence of the 3'-Terminal Region of Clover Yellow Vein Potyvirus Isolated from Calanthe sp.

The sequence of 1399 nucleotides from the 3'region of the RNA of clover yellow vein potyvirus (CIYVV-C) isolated from Calanthe sp. was determined. The capsid protein cistron was composed of 915 nucleotides, and corresponded to a region encoding 305 amino acids with a calculated Mr of 34900: the adjacent 3'non-coding region was 74 nucleotides long. The length of the capsid protein gene of CIYVV-C is longer, but the 3'non-coding region is shorter than those of other CIYVV strains (CIYVV-30.CIYVV-NZ and CIYVV-B). The nucleotide sequence of the capsid protein gene and the 3'non-coding region of CIYVV-C RNA showed significantly higher homology with those of other CIYVV strains. These data suggest that the CIYVV-C capsid gene arose from a frame-shift mutation of the capsid gene of another CIYVV strain. or vice versa. CIYVV-C has a closer affinity to other CIYVV strains and to bean yellow mosaic virus than to the other potyviruses.     

The complete sequence of a sugarcane mosaic virus isolate causing maize dwarf mosaic disease in China

The complete sequence of a potyvirus from maize in Zhejiang Province was determined. The RNA was 9596 nucleotides long, excluding the 3'-poly (A) tail, and there was a single long open reading frame (ORF) of 9192 nts encoding a 346.1 ku polyprotein. The polyprotein had substantial amino acid sequence homology with those encoded by the RNAs of a Chinese isolate of sorghum mosaic virus (SrMV-C) and a Bulgarian isolate of maize dwarf mosaic virus, but it was most closely related to sugarcane mosaic virus (SCMV) isolates, for which only partial sequences have been published. According to the published criteria for distinguishing potyviruses, the sequence reported here is clearly a strain of SCMV, but it also showed a surprisingly high amino acid homology with SrMV-C in the HC-Pro, P3 and Cl proteins.     

The complete sequence of a sugarcane mosaic virus isolate causing maize dwarf mosaic disease in China

The complete sequence of a potyvirus from maize in Zhejiang Province was determined. The RNA was 9596 nucleotides long, excluding the 3′-poly (A) tail, and there was a single long open reading frame (ORF) of 9192 nts encoding a 346.1 ku polyprotein. The polyprotein had substantial amino acid sequence homology with those encoded by the RNAs of a Chinese isolate of sorghum mosaic virus (SrMV-C) and a Bulgarian isolate of maize dwarf mosaic virus, but it was most closely related to sugarcane mosaic virus (SCMV) isolates, for which only partial sequences have been published. According to the published criteria for distinguishing potyviruses, the sequence reported here is clearly a strain of SCMV, but it also showed a surprisingly high amino acid homology with SrMV-C in the HC-Pro, P3 and Cl proteins.     

Further Studies on a Virus Causing a Green Mosaic Disease of Eggplant in Nigeria

A virus reported earlier to cause a green mosaic disease of eggplant in Nigeria was studied in more detail. Its filamentous particles with a normal length of 820 nm reacted in immunoelectron microscopical tests strongly with the homologous antiserum and less strongly with antisera to dioscorea green banding mosaic, groundnut eyespot, zucchini yellow mosaic viruses and to a tomato potyvirus isolate from Taiwan. No reactions were seen with antisera to 25 other potyviruses. Several new host plants were identified. Infected cells contained cylindrical inclusions with scrolls and short curved laminated aggregates and clusters of small vesicles with electron-dense content. Host range and serological reactivities differentiate the virus for which the name eggplant green mosaic virus is suggested from all potyviruses so far known.     

Biological, Serological and Coat Protein Properties of a Strain of Turnip Mosaic Virus Causing a Mosaic Disease of Brassica campestris and B. juncea in India

Biological, serological and coat protein properties of a potyvirus (Poty-Rape) causing a mosaic disease of Brassica campestris and B. juncea in India were investigated. The virus readily infected 4 of the 5 plant species in the family Brassicaceae in which it induced severe systemic mosaic symptoms; it also induced chlorotic and necrotic local lesions in Chenopodium amaranticolor , but failed to infect 4 other species of Chenopodiaceae or 20 species of Amaranthaceae, Apiaceae, Canabinaceae, Compositae, Cucurbitaceae, Euphorbiaceae, Leguminosae and Solanaceae. The virus was transmitted in a non-persistant manner by Myzus persicae, Brevicoryne brassicae and Aphis gossypii. The Average size, of the virus particles in a purified preparation was 740 nm × 12 nm. SDS-PAGE analysis of the viral coat protein showed two major bands of approximately 37 kDa and 31 kDa, a pattern very similar to that of a reference isolate of turnip mosaic virus (TuMV) from the U.S. In Western-blot immunoassay, an antiserum to TuMV reacted with both the coat protein bands of the Poty-Rape islate and the reference TuMV, but not with the coat proteins of four other potyviruses. The high performance liquid chromatographic profile of tryptic peptides from the coat protein of Poty-Rape was found to be very similar to that of the reference TuMV, but differed substantially from those of four other potyviruses. The Poty-Rape isolate is considered to be a distinct strain of, TuMV.     

The Natural Occurrence of Turnip Mosaic Potyvirus in Allium ampeloprasum

An isolate of turnip mosaic potyvirus (TuMV) was obtained from Allium ampeloprasum grown in commercial greenhouses in Israel. Symptoms on infected plants include systemic chlorosis and yellow stripes, accompanied by growth reduction. Leaves were distorted, often showing necrotic flecking. The virus was readily transmitted mechanically, and in a non-persistent manner by aphids, among Allium, Chenopodium. Gomphrena and some Nicotiana spp. Purified preparations contained numerous filamentous particles similar to those observed in crude extracts of infected leaves. Particles from crude plant extracts had a normal length of 806 nm. Cells of infected plants contained cylindrical cytoplasmic inclusions with pinwheel, scrolls and laminated aggregates which indicated the presence of a potyvirus of Edwardson's subgroup III. and which resemble those of turnip mosaic virus (TuMV), The virus reacted strongly with antiserum to typical isolates of TuMV in immunoelectron microscopy and western blotting but not with antisera to several other potyviruses. Based on serological reactivity, electron microscopy, aphid transmission and cytopathology, the virus was identified as an isolate of TuMV.     

Plant virus HC-Pro is a determinant of eriophyid mite transmission

The eriophyid mite transmitted Wheat streak mosaic virus (WSMV; genus Tritimovirus, family Potyviridae) shares a common genome organization with aphid transmitted species of the genus Potyvirus. Although both tritimoviruses and potyviruses encode helper component-proteinase (HC-Pro) homologues (required for nonpersistent aphid transmission of potyviruses), sequence conservation is low (amino acid identity, approximately 16%), and a role for HC-Pro in semipersistent transmission of WSMV by the wheat curl mite (Aceria tosichella [Keifer]) has not been investigated. Wheat curl mite transmissibility was abolished by replacement of WSMV HC-Pro with homologues of an aphid transmitted potyvirus (Turnip mosaic virus), a rymovirus (Agropyron mosaic virus) vectored by a different eriophyid mite, or a closely related tritimovirus (Oat necrotic mottle virus; ONMV) with no known vector. In contrast, both WSMV-Sidney 81 and a chimeric WSMV genome bearing HC-Pro of a divergent strain (WSMV-El Batán 3; 86% amino acid sequence identity) were efficiently transmitted by A. tosichella. Replacing portions of WSMV-Sidney 81 HC-Pro with the corresponding regions from ONMV showed that determinants of wheat curl mite transmission map to the 5'-proximal half of HC-Pro. WSMV genomes bearing HC-Pro of heterologous species retained the ability to form virions, indicating that loss of vector transmissibility was not a result of failure to encapsidate. Although titer in systemically infected leaves was reduced for all chimeric genomes relative to WSMV-Sidney 81, titer was not correlated with loss of vector transmissibility. Collectively, these results demonstrate for the first time that HC-Pro is required for virus transmission by a vector other than aphids.     

Partial Characterization of Nasturtium Mosaic Potyvirus

Nasturtium mosaic virus, hitherto considered to be a carlavirus, was shown to be a member of the potyvirus group by its morphology, capsid protein size, positive reaction with potyvirus group antiserum and the presence in its host of cytoplasmic inclusions ("pinwheels"). It is serologically unrelated to five other well characterized potyviruses.     

Yam mosaic, a new potyvirus infecting Dioscorea cayenensis in the Ivory Coast

The major disease affecting Dioscorea cayenensis in the Ivory Coast is caused by a virus which was transmitted by mechanical inoculation to some Dioscorea spp. and Nicotiana benthamiana . In extracts of D. cayenensis leaves infectivity was lost after 10 min at 60 C but not 55 C and after dilution to 10^-3 but not 10^-2. A purification procedure is described. The virus particles are flexuous filaments c . 785 nm long. The virus was transmitted by four aphid species in the non-persistent manner, and is serologically related to four African potyviruses. The name yam mosaic virus is proposed; the present cryptogram is: */*:*/6:E/E:S/Ve/Ap, potyvirus group.     

Narcissus latent, a virus with filamentous particles and a novel combination of properties

As previously reported, narcissus latent virus (NLV) has flexuous filamentous particles measuring c. 650 nm × 13 nm, is manually transmissible to Nicotiana clevelandii and Tetragonia expansa, and is transmitted by the aphid Myzus persicae following brief acquisition access periods. In contrast to previous reports the virus particle protein has an apparent mol. wt of c. 45 kD. Moreover, infected cells in N. clevelandii leaves contain cytoplasmic inclusion bodies resembling those of potyviruses. In vitro translation of NLV RNA produced only one major product (mol. wt c. 25 kD) which was not precipitated by antisera to virus particle protein or to cytoplasmic inclusion protein. Antisera to 12 potyviruses and nine carlaviruses failed to react with sap containing NLV particles. Similarly antiserum to NLV particles did not react with particles of seven potyviruses or four carlaviruses. A weak reaction was detected between NLV particles and antiserum to particles of maclura mosaic virus (MMV), a virus which resembles NLV in particle morphology and particle-protein size, and in inducing pinwheel inclusions. The cytoplasmic inclusion proteins (CIPs) of NLV, MMV and from narcissus plants with yellow stripe symptoms were serologically inter-related. These proteins were also serologically related to, and had mol. wt similar to, the CIP of members of the potyvirus group. Particles with the size and antigenic specificity of those of NLV were found consistently in narcissus plants with yellow stripe disease. Narcissus latent and narcissus yellow stripe viruses therefore seem to be synonymous and, together with MMV, have properties distinct from those of any previously described virus group.     

Cytopathology of Anthers and Pollen From Lettuce Plants Infected by Lettuce Mosaic Virus

Thin sections of mature anthers and pollen grains from three lettuce (Lactuca sativa) plants infected with lettuce mosaic potyvirus (LMV) were studied by immunogold labelling. Labelled LMV particles were present externally on the exine of pollen grains from all plants, but were observed internally in the pollen grains from only one plant. Within mature pollen grains the virus particles were associated with the cytoplasmic bundle inclusions typical of infection by potyviruses. The tapetal plasmodium and the epidermal and endothecial layers of mature anthers from all infected plants also contained labelled virus particles, together with pinwheel and bundle inclusions.     

Groundnut eyespot virus, a new member of the potyvirus group

A virus causing ‘eyespot’ leaf symptoms in groundnut plants was transmitted by sap-inoculation and by Aphis craccivora in the non-persistent manner. It infected 16 of 72 species from five of 12 families and was easily propagated in Arachis hypogaea and Physalis floridana. The virus has particles c. 13 × 755 nm and is serologically closely related to soybean mosaic and pepper veinal mottle viruses, and more distantly to four other potyviruses. The virus differs in host range, in vitro properties and serological properties from previously described strains of soybean mosaic and pepper veinal mottle viruses. It seems to be a distinct member of the potyvirus group and we propose the name groundnut eyespot virus.     

Some Hosts and Properties of a Potyvirus Infecting Vanilla fragrans (Orchidaceae) in the Kingdom of Tonga

Abstract A potyvirus was isolated from Vanilla fragrans exhibiting leaf distortion, chlorotic and necrotic lesions and vine die-back. The virus can be propagated in Nicotiana clevelandii and N. benthamiana and induces local lesions in Chenopodium amaranticolor and C. quinoa. The flexuous particles have a mean length of 765 nm, pinwheel inclusions are found in systemically infected N. benthamiana leaves and SDS-polyacrylamide gel electrophoresis indicates a single polypeptide of M 32.7 × 10³. The virus is transmissible from N. clevelandii to N. clevelandii by the aphid species Myzus persicae and Aphis gossypii. A polyclonal antiserum raised to the Tongan potyvirus failed to react, with the potyvirus associated with mosaic symptoms of V. tahitensis in French Polynesia and ISEM failed to detect any close relationship to 22 other potyviruses.     

大豆花叶病毒黄淮5号株系的基因组全序列分析

测定了大豆花叶病毒(SMV)我国黄淮5号(Y5)株系的基因组全序列.该病毒基因组全长9*!585个核苷酸,3′-末端具poly(A)尾,包含单一开放读码框,编码一个349.2kD的多聚蛋白.基因组全序列和美国SMV G2和G7株系的核苷酸同源性分别为97.4%和96.9%.多聚蛋白酶解后产生马铃薯Y病毒属典型的10个成熟蛋白.Y5、G2和G7 3个株系的不同成熟蛋白间氨基酸序列的同源性为89.6%～100%.多重比较分析表明,Y5株系P1蛋白N-末端区域与G2和G7存在明显差异.进一步分析显示,这3个株系的6K1、6K2、NIa-Pro、NIa-VPg、NIb蛋白中心区域和CP蛋白高度保守,P1蛋白N-末端,CI和P3蛋白C-末端以及HC-Pro蛋白变异较大,但是美国G2和G7株系已报道序列P1蛋白区域存在可能的测序错误.     

西瓜花叶病毒中国分离株全基因组核苷酸序列测定

西瓜花叶病毒(Watermelon mosaic virus,WMV)是马铃薯Y病毒属(Potyvirus)成员,主要危害西瓜和甜瓜,引起花叶病。在田间,该病害主要由蚜虫以非持久性方式传播。西瓜和甜瓜花叶病在国内陕西、山东、云南、辽宁、山西、新疆、河南和黑龙江等地广泛发生[1-6]。从20世纪80年代中期开始发生,逐渐上升为普遍发生的主要病害。我国大部分地区因西瓜和甜瓜病毒病造成的损失为30%~50%,甚至会绝产,西瓜花叶病毒已经成为制约西瓜和甜瓜高产稳产最主要的因素之一[7]。到目前为止,多数工作集中在对西瓜和甜瓜病毒病的鉴定,在分子生物学上仅限于对CP基因…     

Association of a potyvirus with mosaic disease of gherkin (<Emphasis Type="Italic">Cucumis anguria</Emphasis> L.) in India

A virus associated with severe mosaic disease of gherkin (Cucumis anguria L.) in south India was identified. The infected plants showed mosaic, vein banding, blistering on malformed leaves and fruits. Host range, transmission, serological and electron microscopic studies were carried out to identify the virus. The virus was readily transmitted by Sap inoculation and by aphids in a non-persistent manner. The host range of the virus was mainly limited to cucurbitaceous and chenopodium species. The virus showed positive serological relationships with members of potyvirus genus but not with cucumo, ilar and taspoviruses. Electron microscopy of leaf dip preparation of infected leaves revealed long flexuous filamentous virus particles measuring 750 × 12 nm. On the basis of symptomotology, host range, transmission, serology and particle morphology the virus associated with mosaic disease of gherkin might be the member of potyvirus genus.