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1.
ABSTRACT A membrane feeding system and polymerase chain reaction (PCR) were used to track squash leaf curl virus (SLCV) DNA in whole whitefly body extracts and in saliva, honeydew, and hemolymph of its whitefly vector, Bemisia tabaci, and a whitefly nonvector, Trialeurodes vaporariorum. SLCV ingestion was monitored by PCR in whiteflies that were given acquisition access periods (AAPs) ranging from 0.5 to 96 h on virus-infected plants. SLCV detection by PCR in whole body extracts was considered reflective of virus ingestion. As whiteflies were given longer AAPs, the number of whiteflies that ingested SLCV increased. SLCV DNA was detected in honeydew of vector and nonvector whiteflies, indicating that virions, viral DNA, or both passed unimpeded through the digestive system. SLCV DNA was detected in saliva and hemolymph of B. tabaci, but not in these fractions from nonvector whiteflies, despite virus ingestion by both. Although vector and nonvector whiteflies both ingested SLCV, only in the vector, B. tabaci, did virus cross the gut barrier, enter the hemolymph, or pass into the salivary system. These results suggest that digestive epithelia of nonvector whiteflies did not permit SLCV passage from the gut to hemocoel, whereas virus effectively crossed the analogous gut barrier in vector whiteflies. 相似文献
2.
ABSTRACT A polymerase chain reaction (PCR)-based method for the detection of the curtovirus Beet mild curly top virus (BMCTV, previously named the Worland strain of Beet curly top virus) was developed and used to investigate the BMCTV-beet leafhopper interaction. Using PCR and a BMCTV-specific primer pair, an approximately 1.1-kb BMCTV DNA fragment was amplified from adult leafhoppers and from the organs involved in circulative transmission: the digestive tract, hemolymph, and salivary glands. The temporal distribution of BMCTV in the leafhopper was determined using insects given acquisition access periods (AAPs) ranging from 1 to 48 h on BMCTV-infected shepherd's purse plants. BMCTV was detected in the digestive tract after all AAPs, in the hemolymph after AAPs of 3 h or greater, and in the salivary glands after AAPs of 4 h or greater. The amount of virus detected in the hemolymph and salivary glands increased with AAP length. The virus persisted for up to 30 days in leafhoppers (given a 3-day AAP on BMCTV-infected plants) maintained on corn plants, a nonhost for BMCTV, but transovarial transmission was not detected. These results are consistent with a persistent but nonpropagative mode of circulative transmission. 相似文献
3.
Interactions among maize streak virus disease, leafhopper vector populations and maize cultivars in forest and savanna zones of Nigeria 总被引：1，自引：0，他引：1
C. M. ASANZI N. A. BOSQUE-PEREZ I. W. BUDDENHAGEN D. T. GORDON L. R. NAULT 《Plant pathology》1994,43(1):145-157
Monthly plantings of three maize cultivars with differing resistance/susceptibility to maize streak geminivirus (MSV) and samplings of Cicadulina leafhopper vectors were made from December 1988 to April 1990 in the humid forest and from May to November 1989 in the Guinea savanna zones of Nigeria. High MSV disease incidences (43–56%) were recorded on susceptible cultivar TZB-Gusau in late-season (July-October) plantings. Hybrid 8321-21 showed significantly lower MSV disease incidence and severity than the other two cultivars, TZB-Gusau and 8329-15. Cicadulina species population peaks (5.2-13.5 leafhoppers/m2 ) were observed before the rains ended in savanna locations and after the end of the rains in the forest zone. Cicadulina mbila was the predominant species, whereas C. storeyi (syn. C. triangula ), C. arachidis, C. similis and C. ghaurii were less common. The proportion of viruliferous leafhoppers increased as the season progressed, reaching maxima of 15–25% at the end of the growing season. Interactions between disease incidence, Cicadulina populations, maize cultivars and rainfall are discussed. 相似文献
4.
Jun Ohnishi Toshio Kitamura Fumihiro Terami Ken-ichiro Honda 《Journal of General Plant Pathology》2009,75(2):131-139
We studied the presence of a potential transmission barrier that blocks Tomato yellow leaf curl virus in the nonvector greenhouse whitefly, Trialeurodes vaporariorum. Because T. vaporariorum can ingest and retain the virus after acquisition feeding on an infected plant, comparable to the vector whitefly Bemisia tabaci, circumstance evidence suggested that a transmission barrier presents at location(s) where the virus moves from the digestive
tract lumen to the hemolymph. To provide direct evidence for the site of a transmission barrier in the nonvector insect, we
compared the accumulation levels and localization of the virus between the two species of whiteflies. Quantitative real-time
and conventional PCR analysis showed that accumulation of the virus during acquisition feeding and retention after a short
acquisition period were indistinguishable between the two species, but the circulation of the virus within the whiteflies
differed significantly between the species. In an immunofluorescence analysis using an antibody specific to the coat protein
of the virus, the virus was restricted to the luminal surface of the midgut epithelial cells and did not enter their cytoplasm
or that of the salivary glands in T. vaporariorum. In contrast, the virus was localized within the cytoplasm of the midgut epithelial cells and in the paired salivary glands
of B. tabaci adults. This direct evidence shows that a selective transmission barrier at the luminal membrane surface of midgut epithelial
cells in the nonvector whitefly blocks entrance of the virus into the midgut epithelial cells, resulting in incompetence as
a vector of the virus. 相似文献
5.
在吉林省7个主要甘薯种植区共采集85份甘薯叶片样品,利用小RNA深度测序技术对混合样品进行检测,经RT-PCR和测序验证,鉴定出样品中存在10种病毒,包括6种RNA病毒和4种DNA病毒。分别是马铃薯Y病毒科马铃薯Y病毒属的甘薯羽状斑驳病毒Sweet potato feathery mottle virus (SPFMV)、甘薯潜隐病毒Sweet potato latent virus (SPLV)、甘薯G病毒Sweet potato virus G (SPVG)、甘薯C病毒Sweet potato virus C (SPVC)、甘薯2号病毒Sweet potato virus 2 (SPV2);长线形病毒科毛形病毒属的甘薯褪绿矮化病毒Sweet potato chlorotic stunt virus (SPCSV);双生病毒科菜豆金色花叶病毒属的甘薯曲叶病毒Sweet potato leaf curl virus(SPLCV);玉米线条病毒属的甘薯无症状1号病毒Sweet potato symptomless virus 1 (SPSMV1);花椰菜花叶病毒科杆状DNA病毒属的甘薯杆状DNA病毒B Sweet potato badnavirus B (SPBV-B)和甘薯隐症病毒Sweet potato pakakuy virus (SPPV)。 相似文献
6.
ABSTRACT Whiteflies (Bemisia tabaci, biotype B) were able to transmit Tomato yellow leaf curl virus (TYLCV) 8 h after they were caged with infected tomato plants. The spread of TYLCV during this latent period was followed in organs thought to be involved in the translocation of the virus in B. tabaci. After increasing acquisition access periods (AAPs) on infected tomato plants, the stylets, the head, the midgut, a hemolymph sample, and the salivary glands dissected from individual insects were subjected to polymerase chain reaction (PCR) without any treatment; the presence of TYLCV was assessed with virus-specific primers. TYLCV DNA was first detected in the head of B. tabaci after a 10-min AAP. The virus was present in the midgut after 40 min and was first detected in the hemolymph after 90 min. TYLCV was found in the salivary glands 5.5 h after it was first detected in the hemolymph. Subjecting the insect organs to immunocapture-PCR showed that the virus capsid protein was in the insect organs at the same time as the virus genome, suggesting that at least some TYLCV translocates as virions. Although females are more efficient as vectors than males, TYLCV was detected in the salivary glands of males and of females after approximately the same AAP. 相似文献
7.
Abstract A preliminary survey was made in the most important maize‐growing regions of Ethiopia to record the species of Cicadulina present, their distribution and abundance. Five species of Cicadulina were found, including two not previously reported from Ethiopia. The maize strain of maize streak geminivirus (MSV) occurred predominantly between 450 and 1800 m above sea level, which coincides with the altitudinal range of C. mbila implicating this species as the principal vector of MSV in Ethiopia. The maize strain isolate was indistinguishable from others from elsewhere in Africa. 相似文献
8.
ABSTRACT Maize streak virus (MSV) is best known as the causal agent of maize streak disease. However, only a genetically uniform subset of the viruses within this diverse species is actually capable of producing severe symptoms in maize. Whereas these "maize-type" viruses all share greater than 95% sequence identity, MSV strains isolated from grasses may share as little as 79% sequence identity with the maize-type viruses. Here, we present the complete genome sequences and biological characterization of two MSV isolates from wheat that share approximately 89% sequence identity with the maize-type viruses. Clonal populations of these two isolates, named MSV-Tas and MSV-VW, were leafhopper-transmitted to Digitaria sanguinalis and a range of maize, wheat, and barley genotypes. Whereas the two viruses showed some differences in their pathogenicity in maize, they were both equally pathogenic in D. sanguinalis and the various wheat and barley genotypes tested. Phylogenetic analyses involving the genome sequences of MSV-Tas and MSV-VW, a new maize-type virus also fully sequenced in this study (MSV-VM), and all other available African streak virus sequences, indicated that MSV-Tas and MSV-VW are close relatives that together represent a distinct MSV strain. Sequence analyses revealed that MSV-VM has a recombinant genome containing MSV-Tas/VW-like sequences within its movement protein gene. 相似文献
9.
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. 相似文献
10.
Twenty-four isolates of maize streak virus (MSV) derived from maize, sugarcane and grasses were compared to a maize isolate of the virus (M(N)M) from Nigeria, using symptoms, gel diffusion and ELISA. Fourteen isolates were identified as maize strains, eight other isolates were serologically related to M(N)M but were distinct. In most cases the maize strain could be identified by the symptoms in Zea mays cv. Golden Bantam but symptom expression in grasses was not always sufficient to identify the economically important maize strain. In general, however, symptoms were similar in both grass and maize hosts. Identification by symptoms alone was further complicated by the possibility that some isolates were mixtures. There was no evidence that adaptation to grass hosts occurred, as all isolates could be transmitted to maize. It was not possible to transmit certain strains to the host species from which they were derived, even though they were transmissible to other hosts. This was assumed to be related to vector feeding behaviour. Insect toxin was responsible for certain stunting symptoms, leaf curling and vein enations often associated with MSV. 相似文献
11.
Viral inclusions in monocotyledons infected by maize streak and related geminiviruses 总被引：1，自引：0，他引：1
Isolates of maize streak virus (MSV) were examined by thin-section electron microscopy in plants, assessed for characteristic features of infection and compared with other related geminiviruses infecting monocotyledons from Africa, islands in the Indian Ocean, and the Pacific Island of Vanuatu. Arrays of virus particles, often crystalline, were most often seen in the nucleus. The morphology of the nuclear crystalline arrays was characteristic of certain isolates or groups of isolates (strains). Infected nuclei could be seen in cells from the phloem parenchyma, vascular bundle sheath and mesophyll tissue, and also in epidermal guard cells of plants infected with the maize strain of MSV. The particle arrays varied in morphology from regular rows of virions forming distinctive blocks, to randomly arranged aggregates in certain areas of the nucleus. We consistently failed to find viral crystalline arrays associated with infection of panicum streak virus (PSV) and sugar cane streak virus (SSV) isolates either in these hosts or in maize. Occasionally arrays of MSV particles were found outside the nuclear envelope in physiologically active cells. Accumulations or sheets of MSV particles were seen lining the walls of some phloem companion cells. Crystalline aggregates of particles were frequently observed in the cell vacuole, after lysis of the nuclear membrane of dead cells which made up the chlorotic lesions, the typical symptom of virus infection. Virus preparations from all hosts contained typical geminate particles regardless of the morphology of the virion arrays. The effect on chloroplasts appeared to vary between isolates and this is discussed in relation to lesion colour. The arrangement of virions in the nucleus as a taxonomic character is diagnostic for MSV. Inclusions with crystalline structure found in sieve elements of infected plants were not immunogold labelled when thin sections were probed using antiserum to the virus particles. 相似文献
12.
ABSTRACT Sexual forms of two genotypes of the aphid Schizaphis graminum, one a vector, the other a nonvector of two viruses that cause barley yellow dwarf disease (Barley yellow dwarf virus [BYDV]-SGV, luteovirus and Cereal yellow dwarf virus-RPV, polerovirus), were mated to generate F1 and F2 populations. Segregation of the transmission phenotype for both viruses in the F1 and F2 populations indicated that the transmission phenotype is under genetic control and that the parents are heterozygous for genes involved in transmission. The ability to transmit both viruses was correlated within the F1 and F2 populations, suggesting that a major gene or linked genes regulate the transmission. However, individual hybrid genotypes differed significantly in their ability to transmit each virus, indicating that in addition to a major gene, minor genes can affect the transmission of each virus independently. Gut and salivary gland associated transmission barriers were identified in the nonvector parent and some progeny, while other progeny possessed only a gut barrier or a salivary gland barrier. Hemolymph factors do not appear to be involved in determining the transmission phenotype. These results provide direct evidence that aphid transmission of luteoviruses is genetically regulated in the insect and that the tissue-specific barriers to virus transmission are not genetically linked. 相似文献
13.
Miwa Uchibori Aiko Hirata Masashi Suzuki Masashi Ugaki 《Journal of General Plant Pathology》2013,79(2):115-122
Begomoviruses are transmitted by a single species of vector insect, the whitefly Bemisia tabaci, in a circulative manner. However, the mechanisms of this strict vector specificity have not been clarified. By immunoelectron microscopy, we showed that a begomovirus, Tomato yellow leaf curl virus (TYLCV), can enter midgut epithelial cells of the vector whitefly B. tabaci but not those of a nonvector whitefly, Trialeurodes vaporariorum, belonging to the same family. In midgut epithelial cells of viruliferous B. tabaci, the virus was localized in vesicle-like structures, suggesting endocytosis as an entry mechanism. These structures were also observed in midgut cells of nonviruliferous B. tabaci that had fed on healthy plants and in those of the nonvector T. vaporariorum that had fed on virus-infected plants. Vesicles containing TYLCV particles were observed most frequently in cells in the anterior part of the descending midgut, suggesting that this is the major entry site. These results clearly demonstrated that the virus-containing vector and nonvector whiteflies differ in the cellular localization of the virus and strongly suggest that a critical step in determining the vector insect specificity of begomoviruses is the entry of the viruses into midgut epithelial cells. 相似文献
14.
Elisa Javer-Higginson Isabelle Acina-Mambole José Efrain González Caridad Font Gloria González Ana Lidia Echemendía Emmanuelle Muller Pierre-Yves Teycheney 《European journal of plant pathology / European Foundation for Plant Pathology》2014,138(1):157-166
Banana streak viruses (BSV) belong to the genus Badnavirus of the family Caulimoviridae. They cause banana streak disease on banana and plantains worldwide. The recent detection of BSV in Cuba has prompted a nationwide research effort focused on the occurrence, prevalence and diversity of BSV species on dessert type banana on the island. Indexing by multiplex immunocapture-PCR (M-IC-PCR) performed on samples collected throughout the country showed that the overall prevalence of Banana streak OL virus, Banana streak GF virus and Banana streak IM virus is low in Musa acuminata genotypes in Cuba. However, the prevalence of BSV species Mysore (BSMYV) was surprisingly high in samples of cv Yangambi km5 collected from distinct and distant locations. The presence in Cuba of an as yet unreported BSV species was also investigated, showing that Banana steak VN virus is also present in Musa acuminata genotypes. 相似文献
15.
ABSTRACT We devised a rapid technique for the objective and precise assessment of both the pathogenicity of maize streak virus (MSV) isolates and the MSV resistance of maize genotypes. The technique involves the use of agroinoculation to infect maize seedlings and the objective symptom evaluation by quantification of infection rates, stunting, and chlorotic leaf areas. In assessing the MSV resistance of 19 maize genotypes, we describe how the use of differentially virulent virus isolates enables the analysis of MSV resistance phenotypes, ranging from extremely susceptible to completely immune. We further demonstrate how quantification of chlorotic leaf areas by image analysis permits differentiation between degrees of MSV resistance that are indistinguishable from one another using currently employed symptom assessment approaches. Using chlorotic area measurements, we quantify the virulence of a diverse group of 10 MSV isolates and, through agroinoculation of differentially susceptible maize genotypes, we demonstrate the use of our technique in evaluating the pathogenicity of these isolates. 相似文献
16.
B. Reynaud H. Delatte M. Peterschmitt D. Fargette 《European journal of plant pathology / European Foundation for Plant Pathology》2009,123(3):269-280
The epidemiologies of Maize streak virus (MSV), Maize stripe virus (MSpV), and Maize mosaic virus (MMV) were compared in La Réunion over a three year-period. Disease incidence caused by each virus was assessed, and the
leaf and planthopper vector populations (Cicadulina mbila and Peregrinus maidis) were estimated in weekly sowings of the temperate, virus-susceptible maize hybrid INRA 508 and of the composite resistant
cv. IRAT 297. MSV caused the most prevalent disease and MMV the least, with lower incidences in cv. IRAT 297 than in INRA
508. For each plant–virus–vector combination, (a) disease incidence was positively correlated to vector abundance, often with
1 month of time lag; (b) annual periodicity of disease incidence and of vector numbers was consistent with highest autocorrelations
and a time lag of 12 months, (c) vector numbers and disease incidence were closely associated with temperature fluctuations,
both remaining relatively constant below 24°C and increasing rapidly above this threshold temperature. By contrast, relationships
with rainfall and relative humidity (RH) were less consistent. Overall, 63 to 80% of the variance of disease incidence was
explained through stepwise regression with vector number, temperature, and sometimes also rainfall or RH. The simple epidemiological
model proposed underlines the close link between increased temperature and possible (re-) emergence of these three diseases
in a maize cropping area. 相似文献
17.
ABSTRACT The specificity of vector transmission of Flavescence dorée phytoplasma (FDP) was tested by injecting FDP, extracted from laboratory-reared infective Euscelidius variegatus, into specimens of 15 other hemipteran insect species collected in European vineyards. Concentrations of viable phytoplasma extracts and latency in vectors were monitored by injection of healthy-reared E. variegatus leafhoppers. Based on these preliminary results, insects were injected by using phytoplasma extracts that ensured the highest rate of FDP acquisition and transmission by E. variegatus. Transmission into an artificial diet through a Parafilm membrane about 3 weeks after insect injection was attempted. FDP-injected insects that belonged to 15 hemipteran species were confined in cages and fed through the membrane for a 4- to 5-day inoculation access period. FDP DNA was detected by polymerase chain reaction (PCR) in the feeding buffer fed upon by Anoplotettix fuscovenosus, Aphrodes makarovi,E. variegatus, and Euscelis incisus. PCR amplification with specific primers detected FDP DNA in injected insects of all test insect species. Band intensity was positively correlated with the transmissibility of FDP. Transmission of FDP to plants by feeding was confirmed for Anoplotettix fuscovenosus, E. variegatus, and Euscelis incisus, but not for Aphrodes makarovi. Our results suggest that vector competency of FDP is restricted to specimens belonging to the family Cicadellidae, subfamily Deltocephalinae. 相似文献
18.
19.
ABSTRACT Interactions between viral and cellular membrane fusion proteins mediate virus penetration of cells for many arthropod-borne viruses. Electron microscope observations and circumstantial evidence indicate insect acquisition of tomato spotted wilt virus (TSWV) (genus Tospovirus, family Bunyaviridae) is receptor mediated, and TSWV membrane glycoproteins (GP1 and GP2) serve as virus attachment proteins. The tospoviruses are plant-infecting members of the family Bunyaviridae and are transmitted by several thrips species, including Frankliniella occidentalis. Gel overlay assays and immunolabeling were used to investigate the putative role of TSWV GPs as viral attachment proteins and deter mine whether a corresponding cellular receptor may be present in F. occidentalis. A single band in the 50-kDa region was detected with murine monoclonal antibodies (MAbs) to the TSWV-GPs when isolated TSWV or TSWV-GPs were used to overlay separated thrips proteins. This band was not detected when blots were probed with antibody to the non-structural protein encoded by the small RNA of TSWV or the TSWV nucleocapsid protein, nor were proteins from nonvector insects labeled. Anti-idiotype antibodies prepared to murine MAbs against GP1 or GP2 specifically labeled a single band at 50 kDa in Western blots and the plasmalemma of larval thrips midguts. These results support the putative role of the TSWV GPs as viral attachment proteins and identified potential cellular receptor(s) in thrips. 相似文献
20.
P. Caciagli D. Bosco Lina Al-Bitar 《European journal of plant pathology / European Foundation for Plant Pathology》1995,101(2):163-170
Relationships of an Italian isolate of tomato yellow leaf curl geminivirus from Sardinia (TYLCV-S) with its whitefly vectorBemisia tabaci were studied by means of experimental transmissions from tomato to tomato plants. TYLCV-S was confirmed to be transmitted in a persistent, circulative manner. The minimum latent period in the vector was between 17 and 20 h from the beginning of the acquisition access period (AAP). The maximum retention of infectivity was 8 days from the end of the AAP. Both acquisition and inoculation feeding times influenced the detected proportion of infective insects, with patterns well described by an exponential model. Acquisition was more efficient than inoculation. Males were significantly less efficient vectors than females. Nymphs were as efficient as adults in acquiring the virus. The length of AAP influenced both the retention of infectivity, and the pattern of transmission in serial transfer transmission tests with individual females. No significant difference in transmission efficiency was detected between two colonies ofB. tabaci, one inducing typical silverleaf symptoms on squash, the other inducing only mild symptoms with more than 50 whiteflies per plant. The phenomenon of periodic acquisition was not unequivocally proved for TYLCV-S.Research supported by the National Research Council of Italy, Special Project RAISA, Sub-project N. 2. Paper N. 1961.Supported by a grant from the Istituto Agronomico Mediterraneo, Valenzano (Bari), Italy. 相似文献