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1.
ABSTRACT Schizaphis graminum is an important insect pest of several grain crops and an efficient vector of cereal-infecting luteoviruses and poleroviruses. We examined the virus transmission characteristics of several distinct populations and various developmental stages of the aphid. Seven well-characterized S. graminum biotypes maintained at the USDA-ARS laboratory in Stillwater, OK, and two biotypes maintained in New York (one collected in Wisconsin and the other collected in South Carolina) were tested for their ability to transmit five viruses that cause barley yellow dwarf disease (BYD). Four of the Oklahoma biotypes, which do not commonly colonize agronomic crops, and the Wisconsin biotype, were efficient vectors of several viruses. The three other Oklahoma biotypes, which do colonize agronomic crops, and the South Carolina biotype, were poor vectors of all five viruses. Thus, the vector specificity long associated with viruses causing BYD is not limited to the level of aphid species; it clearly extends to populations within a single species. S. graminum nymphs are reported to be more efficient vectors of Barley yellow dwarf virus (BYDV-SGV) than are adults. This was confirmed only for the Wisconsin biotype, but not for the other eight S. graminum biotypes. Thus, there does not appear to be a generalized developmentally regulated barrier to the transmission of BYDV-SGV in S. graminum. Furthermore, the developmentally regulated vector competency observed in the Wisconsin biotype did not extend to other viruses. BYDV-PAV and Cereal yellow dwarf virus-RPV were transmitted with similar efficiency by all S. graminum biotypes when acquired by nymphs or adults. 相似文献
2.
For many years, control methods against aphid-transmitted barley/cereal yellow dwarf viruses (B/CYDV) in cereal fields were mainly based on the use of neonicotinoid (NNI)-coated seeds. The ban of NNI by the EU in 2018 has reinforced the interest of the scientific community in the characterization of genetic resources and biological protections to find alternatives to chemicals for the management of B/CYDV. Eleven BYDV-susceptible wheat varieties were tested using a set of experimental procedures to evaluate their potential to alter parameters linked to the biology of aphids (Rhopalosiphum padi) and spread of virus (BYDV-PAV). Moreover, two natural-based substances (azadirachtin and mineral oil) were tested for their impact on the ability of aphids to survive, colonize and transmit the virus. Results showed that the 11 genotypes tested have a level of susceptibility to virus infection similar to the susceptible reference cv. Rubisko. However, when characterization focused on virus load, latency period and aphid fecundity, partial resistance phenotypes were observed for some cultivars. Furthermore, azadirachtin increased aphid mortality and decreased aphid fecundity. Thus, in addition to genes described for their ability to limit B/CYDV infections, the genetic backgrounds of B/CYDV-susceptible wheat cultivars and azadirachtin-based treatment should be considered for future management strategies against yellow dwarf disease. 相似文献
3.
The RMV strain of Barley yellow dwarf virus (BYDV-RMV) is an unassigned member of the Luteoviridae that causes barley yellow dwarf in various cereal crops. The virus is most efficiently vectored by the aphid Rhopalosiphum maidis, but can also be vectored with varying efficiency by R. padi and Schizaphis graminum. Field collections of alate aphids migrating into the emerging winter wheat crop in the fall of 1994 in central New York identified a high proportion of R. padi transmitting BYDV-RMV. This prompted a comparison of the BYDV-RMV isolates and the R. padi populations found in the field with type virus and aphid species maintained in the laboratory. A majority of the field isolates of BYDV-RMV were similar to each other and to the type BYDV-RMV isolate in disease severity on oat and in transmission by the laboratory-maintained population of R. maidis and a field-collected population of R. maidis. However, several field populations of R. padi differed in their ability to transmit the various BYDV-RMV isolates. The transmission efficiency of the R. padi clones was increased if acquisition and inoculation feeding periods were allowed at higher temperatures. In addition, the transmission efficiency of BYDV-RMV was significantly influenced by the aphid that inoculated the virus source tissue. In general, BYDV-RMV transmission by R. padi was higher when R. padi was the aphid that inoculated the source tissue than when R. maidis was the inoculating aphid. The magnitude of the change varied among virus isolates and R. padi clones. These results indicate that, under certain environmental conditions, R. padi can play a significant role in the epidemiology of BYDV-RMV. This may be especially significant in regions where corn is a major source of virus and of aphids that can carry virus into a fall-planted wheat crop. 相似文献
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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.
近年来植物病毒病频发,严重制约着农作物的产量与品质。绝大多数植物病毒依赖媒介昆虫进行传播,而传播的关键是病毒如何突破昆虫的肠屏障、唾液腺屏障和卵屏障等多个生物屏障。植物病毒一方面利用其外壳蛋白或非结构蛋白突破媒介昆虫的中肠屏障和唾液腺屏障;另一方面则与昆虫体内卵黄原蛋白、共生菌以及精子表面蛋白发生特异性互作,促进病毒跨越卵障碍,最终实现病毒在昆虫体内复制。此外,植物病毒还能通过侵染寄主植物影响其防御性状,间接改变媒介昆虫生理及其行为反应,促进病毒在植物间的传播。该研究对植物病毒突破昆虫生物屏障的分子机制,以及植物病毒-植物-媒介昆虫互作对于病毒传播的影响进行了综述,并对阻断病毒传播的方法进行展望。 相似文献
6.
很多植物病毒经介体昆虫以持久循回型的方式水平传播至寄主韧皮部致病，而唾液腺是介体昆虫持久传毒的重要器官，也是植物病毒在介体昆虫内循回需要克服的最后一道防线。持久性植物病毒要完成水平传播，必须突破昆虫唾液腺屏障的阻碍，因此病毒和介体昆虫间形成了“攻”与“守”的较量与对决。揭示持久性植物病毒克服昆虫唾液腺屏障，实现水平传播的机制，对病害控制具有重要意义。该文着眼于介体昆虫唾液腺在持久传毒过程中的重要功能，回顾了虫传植物病毒突破介体昆虫唾液腺侵入屏障和释放屏障的分子机制，探讨了昆虫唾液蛋白通过调节植物或昆虫的适应性和行为促进或抑制病毒水平传播的功能，为制定阻断介体昆虫传播植物病毒途径的防控策略提供理论依据。 相似文献
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Non-crop plants such as grasses and volunteer plants are an inseparable part of the flora of crop fields and can influence virus incidence in crop plants. The presence of grasses as virus reservoirs can lead to a higher probability of virus incidence in crop plants. However, the role of reservoirs as an inoculum source in agricultural fields has not been well studied for many viral diseases of crops. Grasses have been found to constitute potential reservoirs for cereal-infecting viruses in different parts of the world. This study revealed that cereal-infecting viruses such as wheat dwarf virus (WDV), barley yellow dwarf viruses (BYDVs), and cereal yellow dwarf virus-RPV (CYDV-RPV) can be found among ryegrass growing in or around winter wheat fields. Phylogenetic analysis showed that a WDV isolate from ryegrass was a typical WDV-E isolate that infects wheat. Similarly, a ryegrass isolate of barley yellow dwarf virus-PAV (BYDV-PAV) grouped in a clade together with other BYDV-PAV isolates. Inoculation experiments under greenhouse conditions confirmed that annual ryegrass of various genotypes can be infected with WDV to a very low titre. Moreover, leafhoppers were able to acquire WDV from infected ryegrass plants, despite the low titre, and transmit the virus to wheat, resulting in symptoms. Information from the grass reservoir may contribute to improving strategies for controlling plant virus outbreaks in the field. Knowledge of the likely levels of virus in potential reservoir plants can be used to inform decisions on insect vector control strategies and may help to prevent virus disease outbreaks in the future. 相似文献
8.
蚜虫能够传播上百种植物病毒,是最重要的农业介体昆虫之一。蚜虫在刺探和取食植物过程中,唾液组分会连同附着在口针中的病毒粒子一同被分泌进入植物内,在调节植物诱导抗性、病毒侵染扩散、介体昆虫行为等过程中均有重要作用。本文围绕蚜虫传播病毒和获取病毒2个关键过程,总结分析了蚜虫独特的刺吸取食行为与传毒效率和获毒效率之间的联系;针对取食活动中关键的唾液蛋白在调控植物免疫抗性、帮助病毒侵染过程中的功能,阐述了蚜虫高效传播非持久病毒的分子基础;针对蚜虫的获毒过程,综述了病毒侵染植物间接调控蚜虫趋向和行为的作用方式。这些研究的开展将为解释蚜虫和病毒协同侵染的分子机制以及有效开展基于蚜虫取食行为调控的病虫害防控新技术提供思路。 相似文献
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Muhammad Ali Sidra Anwar Malik Nawaz Shuja Rajiv Kumar Tripathi Jaswinder Singh 《European journal of plant pathology / European Foundation for Plant Pathology》2018,151(4):841-860
Luteoviruses are economically important plant viruses. Specifically, barley yellow dwarf virus is epiphytotic to almost all small-grain cereal growing areas. The disease cycle is complex. This luteovirus has evolved several intelligent mechanisms to communicate with both plant and phloem-feeding insect-vector aphid. Environmental cues influence disease severity, aphid infestation and viral load. Within an aphid, virus circulates persistently in a non-propagative manner and is transmitted selectively to the host plants. Selection of viruses within aphids has a role in virus isolate prevalence over a specific area. In the host-plant system, the virus has to release its single sense-strand RNA genome (approx. 5.6 to 6 kb), translate and subsequently replicate its genome using its own replicase and host machinery. This review summarizes our current understanding of disease epidemiology and reviews the current literature encompassing viral infectivity, economic impact and control measures. 相似文献
11.
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
12.
H. LECOQ M. RAVELONANDRO C. WIPF-SCHEIBEL M. MONSION B. RACCAH J. DUNEZ 《EPPO Bulletin》1994,24(3):555-559
Transgenic Nicotiana benthamiana plants expressing the coat protein of an aphid-transmissible strain of plum pox potyvirus (PPV-D) were infected with an aphid non-transmissible strain of another potyvirus, zucchini yellow mosaic potyvirus (ZYMV-NAT). Non-viruliferous Myzus persicae could acquire and transmit ZYMV-NAT from these plants but not from infected N. benthamiana control plants (not transformed, or transformed by the vector alone). Immunosorbent electron microscopy experiments using the decoration technique revealed that ZYMV-NAT virus particles in the infected transgenic plants expressing the PPV coat protein could be coated not only with ZYMV antibodies but also, on segments of the particles, with PPV antibodies. This suggests that aphid transmission of ZYMV-NAT occurred through heterologous encapsidation, and reveals a potential risk of releasing genetically engineered plants expressing viral coat proteins into the environment. 相似文献
13.
Transmission of barley yellow dwarf virus by cereal aphids collected from different habitats on cereal farms 总被引：1，自引：1，他引：1
Cereal aphids were collected from cereal crops, from Poa annua within cereal fields, from Lolium perenne pastures and from wild grasses in hedge bottoms and around farm buildings. The frequency of barley yellow dwarf virus (BYDV) transmission was assessed by aphid transmission tests. There were differences in transmission rates between aphid species, between host species and between years. The transmission rates of Rhopalosiphum padi from the different host species were broadly similar whereas for Sitobion avenae, P. annua within cereal fields was significantly better than the other host species. Wild grasses other than P. annua were relatively poor sources of virus. A large percentage of aphids frequently transmitted more than one strain, suggesting that host plants are often infected with more than one BYDV strain. 相似文献
14.
S. Cohen 《Phytoparasitica》1981,9(1):69-76
Spread of the aphid-transmitted cucumber mosaic virus (CMV) and potato virus Y (PVY) in pepper plots was markedly reduced by growing the plants under a white coarse-net cover permitting normal development of the plants. This net also reduced the winged aphid population on the plants by more than 40 times. Light grey and yellow nets also reduced virus spread and aphid populations, but were much less effective than white ones. The nets do not act as a mechanical barrier to aphids. It is suggested that under white and grey netting, aphid repellency and microclimatic conditions are the primary causes of virus check, while the controlling effect of the yellow nets may be explained by their being more attractive to aphids than the plants. A reduction of “background effect” and a limiting of the aphids’ vision range by nets are probably other factors involved in the protective mechanism. 相似文献
15.
The tospoviruses Tomato spotted wilt virus (TSWV), Tomato chlorotic spot virus (TCSV), Groundnut ringspot virus (GRSV) and Chrysanthemum stem necrosis virus (CSNV) are well-known pathogens on tomato in Brazil. The thrips species Frankliniella occidentalis , F. schultzei , Thrips tabaci and T. palmi were studied for their competence to transmit these tospoviruses. Frankliniella occidentalis transmitted all four tospoviruses with different efficiencies. Frankliniella schultzei transmitted TCSV, GRSV and CSNV. Although F. schultzei has been reported as a vector of TSWV, the F. schultzei population in the present study did not transmit the TSWV isolate used. A population of T. tabaci known to transmit Iris yellow spot virus (onion isolate) did not transmit any of the studied tospoviruses, and nor did T. palmi . Replication of these tospoviruses could be demonstrated by ELISA, not only in the thrips species that could transmit them, but also in those that could not. The results strongly suggest that competence to transmit is regulated not only by the initial amount of virus acquired and replication, but also by possible barriers to virus circulation inside the thrip's body. 相似文献
16.
M. J. Foxe 《European journal of plant pathology / European Foundation for Plant Pathology》1992,98(2):13-20
Conventional breeding methods based primarily on the principles of Mendelian genetics have provided the basis for the majority of resistance to viruses in potato cultivars. This development of resistant cultivars has resulted from sexual hybridisation followed by selection of the best genetic recombinant. Selection is one of the most powerful tools available for crop improvement. Successful selection depends on reproducible genetic variability, ability to identify genetically superior individual plants or families, populations large enough to ensure the likely occurrence of rare genetic combinations, and the combination of resistance expression with commercial utility. Resistance to the major potato viruses namely potato virus A, potato virus M, potato virus S, potato virus X, potato virus Y and potato leafroll virus has been studied and selected for. A number of different types of resistance have been identified including (a) major gene resistance; (b) minor gene resistance; and (c) immunity. With the exception of potato leafroll virus, stable resistance to the other viruses has been achieved either singly or in combination in a range of potato cultivars. In addition for both potato leafroll virus and potato virus Y, the focus has been on the development of resistance to aphid transmission of the viruses. 相似文献
17.
ABSTRACT Strains of the chestnut blight fungus, Cryphonectria parasitica, have been genetically engineered to contain an integrated full-length cDNA copy of the prototypic virulence-attenuating hypovirus CHV1-EP713. Unlike natural hypovirulent C. parasitica strains, these transgenic hypovirulent strains are able to transmit virus to ascospore progeny under laboratory conditions. This ability provides the potential to circumvent barriers to cytoplasmic virus transmission imposed by the fungal vegetative incompatibility system. During July 1994, transgenic hypovirulent strains were introduced into a Connecticut forest site (Biotechnology Permit 94-010-01). Subsequent analysis of the release site confirmed hypovirus transmission from transgenic hypovirulent strains to ascospore progeny under field conditions. Additionally, it was possible to recover transgenic hypovirulent strains from the test site as long as 2 years after the limited, single-season release. Evidence also was obtained for cytoplasmic transmission of transgenic cDNA-derived hypovirus RNA, including transmission to mycelia of a virulent C. parasitica canker after treatment with conidia of a transgenic strain. Finally, a transgenic hypovirulent strain was recovered from a superficial canker formed on an untreated chestnut tree. Genetic characteristics of the recovered strain suggested that the canker was initiated by an ascospore progeny derived from a cross involving an input transgenic hypovirulent strain. The durability of a molecular marker for field-released cDNA-derived hypovirus RNA is discussed. 相似文献
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ABSTRACT Only larval thrips that acquire Tomato spotted wilt virus (TSWV), or adults derived from such larvae, transmit the virus. Nonviruliferous adults can ingest virus particles while feeding on TSWV-infected plants, but such adult thrips have not been shown to transmit TSWV. Immunofluorescence microscopy was used to show that thrips 1, 5, 10, and 20 days after adult emergence (DAE) fed on TSWV-infected plants acquired TSWV with virus replication and accumulation occurring in both epithelial and muscle cells of Frankliniella fusca (tobacco thrips [TT]) and F. occidentalis (western flower thrips [WFT]), as indicated by immunodetection of the nonstructural (NSs) protein encoded by the small RNA and the nucleocapsid (N) protein, respectively. Adult WFT acquired TSWV more efficiently than TT. There was no significant effect of insect age on TSWV acquisition by TT. In contrast, acquisition by adult WFT at 1 and 5 DAE was higher than acquisition at 10 and 20 DAE. Subsequent transmission competence of adult cohorts was studied by vector transmission assays. All adult thrips tested that had an acquisition access period as an adult were unable to transmit the virus. These results indicate the susceptibility of adult TT and WFT to infection of midgut cells by TSWV and subsequent virus replication and confirm earlier studies that adult thrips that feed on virus-infected plants do not transmit the virus. The role of a tissue barrier in TSWV movement and infection from midgut muscle cells to the salivary glands is discussed. 相似文献