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1.
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   

2.
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   

3.
ABSTRACT If acquisition access feeding (AAF) is first given after adult eclosion, none of the nine thrips species able to serve as tospovirus vectors can become infective. The previous cellular investigations of this phenomenon, carried out only in Frankliniella occidentalis, suggested that infectivity was prevented because the type member of the tospoviruses, Tomato spotted wilt virus (TSWV), was unable to enter the midgut of adult thrips. The present study extends a cellular view of tospovirus-thrips interactions to a species other than the western flower thrips, F. occidentalis. Our findings show that TSWV enters and replicates within the midgut of adult Thrips setosus, but does not infect cells beyond the midgut epithelia. After AAF as adult, TSWV replicated in T. setosus midgut cells as indicated by significant increases in nucleocapsid (N) protein detected by double-antibody sandwich enzyme-linked immunosorbent assay, and the presence of inclusions containing the S RNA-encoded nonstructural and N proteins revealed by microscopic observations. Electron microscopic observations of adult insects showed that no infection occurred in cells beyond the midgut epithelia, and insects subsampled from the same cohorts could not transmit TSWV. In contrast, electron microscopy observations of larval T. setosus revealed that TSWV infected the midgut and muscle cells, and adult insects developing from these cohorts had infected salivary glands and were able to transmit TSWV. Mature virions were observed only in the salivary glands of adults developing from infected larvae. Our findings suggest that the barrier to infectivity in T. setosus adults differs from that shown for F. occidentalis adults.  相似文献   

4.
Tomato spotted wilt virus (TSWV) was isolated from pepper, tomato, eggplant, broad bean, lettuce, basil, chrysanthemum, aster, New Guinea impatiens, anemone and gloxinia plants. Virus identification was based on host range, vector transmission, serology and electron microscopy. TSWV was readily detected by ELISA in naturally or artificially infected cultivated or weed plants. The virus was also detected in individual F. occidentalis thrips. The spread of TSWV in vegetable and ornamental plants in greenhouses and/or in the open is related to the close relationship of the virus with the vector.  相似文献   

5.
ABSTRACT The effect of Tomato spotted wilt virus (TSWV) infection on plant attractiveness for the western flower thrips (Frankliniella occidentalis) was studied. Significantly more thrips were recovered on infected than were recovered on noninfected pepper (Capsicum annuum) plants in different preference tests. In addition, more offspring were produced on the virus-infected pepper plants, and this effect also was found for TSWV-infected Datura stramonium. Thrips behavior was minimally influenced by TSWV-infection of host plants with only a slight preference for feeding on infected plants. Offspring development was positively affected since larvae hatched earlier from eggs and subsequently pupated faster on TSWV-infected plants. These results show a mutualistic relationship between F. occidentalis and TSWV.  相似文献   

6.
Squash blotting on nitrocellulose membranes was used to detect tomato spotted wilt virus (TSWV) in individual Frankliniella occidentalis adult thrips using a specific polyclonal antiserum. This method offers a simple and reliable procedure to test a large number of thrips and was less time-consuming than alternative techniques available. A 95% agreement was found between the results of squash-blot and plant transmission assay. Based on this agreement, this technique was used to study the relative number of viruliferous thrips in F. occidentalis field populations collected from a farm in Catalonia where TSWV causes important economic losses. The percentages of viruliferous individuals detected from a total of 1509 collected thrips increased from 0% to 2% in the different surveys conducted in the 1993 growing season. Squash-blot proved to be a rapid and inexpensive technique to screen TSWV viruliferous thrips from field populations. The results obtained by this method could be used together with other epidemiological data to forecast TSWV-induced diseases.  相似文献   

7.
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   

8.
Tospoviruses infecting vegetable crops in Israel   总被引：1，自引：0，他引：1  
Symptoms of vein clearing, stem necrosis, curling, necrotic spots and rings on the leaves associated with infection by tomato spotted wilt tospovirus (TSWV) were documented among vegetable crops growing in commercial glasshouses and open fields in Israel. Plants exhibiting symptoms were collected, from 1994-01 to 1998-12. Among cultivated vegetable crops analysed for TSWV by ELISA, the following plants were found to be infected: tomato, capsicum, aubergine, lettuce, cabbage and cucumber. These incidences of the virus were all correlated with the occurrence in high population of Frankliniella occidentalis. Transmission of the virus from infected Datura stramonium to Petunia leaf discs, by F. occidentalis , was up to 26%. TSWV antigens were readily detected by ELISA in seeds harvested from naturally infected vegetable crops. However, we failed to show virus transmission to the progeny plants. Iris yellow spot tospovirus (IYSV) was detected in onion. High incidence of the disease was associated with large populations of Thrips tabaci.  相似文献   

9.
黑龙江地区番茄斑萎病毒的鉴定及其部分生物学特征分析   总被引：2，自引：0，他引：2  
近年来,番茄斑萎病毒Tomato spotted wilt tospovirus (TSWV)在我国多个地区发生严重危害。本研究采用小RNA深度测序和RT-PCR相结合的方法对采自黑龙江的番茄病毒病样品中的病毒进行了鉴定。提取番茄样品的RNA并构建小RNA文库进行测序,数据分析发现比对至TSWV基因组的reads数占比对到病毒核酸总reads数的92.64%,表明侵染此番茄样品的病原物可能是TSWV。利用RT-PCR方法进一步确定侵染此番茄样品的病毒为TSWV,将其命名为TSWV-HLJ1。对TSWV-HLJ1的核苷酸序列进行分析并构建系统进化树,结果表明TSWV-HLJ1与TSWV云南甜椒分离物(TSWV-YNgp)的亲缘关系最近。介体传毒试验表明,西花蓟马可将TSWV-HLJ1传播感染健康寄主植物。摩擦接种试验表明,TSWV黑龙江分离物能够侵染本氏烟、辣椒和番茄。这是我国首次报道在黑龙江地区发现TSWV的危害。  相似文献   

10.
It is government policy in Britain to prevent the introduction of alien pests and to eradicate any of economic importance as soon as possible, should they be found in Britain. In recent years a series of polyphagous pests have been introduced into glasshouses in Britain, including Liriomyza trifolii and L. huidobrensis, Frankliniella occidentalis, Opogona sacchari, Bemisia tabaci and Spodoptera littoralis. Of these, only F. occidentalis is no longer subject to eradication and is now established in Britain. The measures taken to eradicate these pests are discussed. Emphasis is given to the unusual technical problems presented by each pest. These problems include the differing pest life histories and the tolerance of pesticides. Crop husbandry and pesticide approval can affect the choice of eradication strategy. Where possible, the eradication strategy is integrated with biological control.  相似文献   

11.
ABSTRACT Using protein blot assays, a 94-kDa thrips protein was identified that exhibited specific binding to tomato spotted wilt virus (TSWV) particles. Renaturation of the 94-kDa protein, which is conserved among the two major vector species of TSWV, Frankliniella occidentalis and Thrips tabaci, was crucial for its virus-binding properties, whereas under the same conditions no specific binding was observed with aphid (Myzus persicae) proteins. The 94-kDa protein species was present in all developmental stages of both vectoring thrips, whereas it was present mainly in the adult stage of a nonvectoring thrips species, Parthenothrips dracenae. Using antibodies against the different TSWV structural proteins, the G2 envelope glycoprotein was identified as the viral determinant involved. Because the virus-binding protein is present throughout the thrips body, but not in the gut, it may represent a receptor protein involved during circulation of the virus through its vector but probably not during viral uptake in the midgut.  相似文献   

12.
Tomato spotted wilt tospovirus (TSWV) infected plants and western flower thrips (Frankliniella occidentalis Perg., WFT) adult population densities were monitored during 1993 and 1994 in field tomatoes in Northeastern Spain. The proportion of viruliferous WFT adults in field populations was quantified. A significant association has been found between early population densities of WFT adult thrips and final TSWV incidence for early transplanted tomato crops. In contrast, for late transplanted tomato crops, whereas similar high final disease incidences of TSWV could be attained, very low WFT adult population densities were always detected. The significantly higher infectious potential of WFT populations collected during the early growth stages of late transplanted tomatoes could be relevant for the TSWV incidences attained in spite of the low thrips numbers detected.  相似文献   

13.
The abilities of different isolates of tomato spotted wilt tospovirus (TSWV) collected from northeastern and eastern Spain to infect 10 host species, and to be acquired and transmitted by the western flower thrips (WFT), Frankliniella occidentalis were compared. Two isolates of TSWV from a single source plant could be separated according to the different type of local lesions they induced in Nicotiana glutinosa. Host ranges of the studied TSWV isolates were very similar, but differences were found in the symptoms induced and in their capacity to infect specific hosts systemically. Lycopersicon esculentumDatura stramonium were evaluated for their potential as virus acquisition host species. The proportion of transmitter adult thrips obtained from WFT larvae fed on L. esculentum was greater than from D. stramonium. No differences were detected between TSWV isolates in their ability to be acquired and transmitted by WFT. No evidence was obtained of alterations in TSWV particles which could affect WFT transmissibility due to the repeated mechanical transfers used to clone the isolates. Our findings do not support the existence of pathological effects of TSWV on WFT.  相似文献   

14.

This study represents the first attempt to improve insecticide contact using the dodecyl acetate component of the alarm pheromone of the western flower thrips ( Frankliniella occidentalis Pergande ). Dodecyl acetate dissolved in ethanol was added to both fipronil and maldison and used in three spray applications (7 days apart) against field infestations of F. occidentalis on strawberries in two separate trials. Fipronil alone was highly effective against larvae and to a lesser extent against adults; however, the addition of dodecyl acetate did not significantly enhance thrips mortality. Although maldison was significantly less effective against adults and larvae, the larval mortality rate was significantly increased with the addition of dodecyl acetate. In one trial, dodecyl acetate applied on its own caused a significant reduction in larval numbers. Frequent insecticide applications are recommended for control of F. occidentalis in Australia because of the short-term effectiveness of most insecticides. This may hasten the development of insecticide resistance, which is already evident in F. occidentalis populations across the continent. Hence, either cultural methods, biological control agents or more effective chemicals need to be identified. This study has shown that there is potential for dodecyl acetate to enhance insecticide control of F. occidentalis .  相似文献   

15.
天敌昆虫和生防菌的联合应用对害虫防控具有潜在的增效作用。东亚小花蝽Orius sauteri是目前常用的捕食性天敌之一, 被广泛用于温室蓟马、粉虱等害虫的防治。金龟子绿僵菌Metarhizium anisopliae寄主广泛, 可有效防治多种温室害虫, 且相对安全。为探索东亚小花蝽与金龟子绿僵菌联用的控害效果, 本文在室内和田间条件下研究了二者对烟粉虱Bemisia tabaci和西花蓟马Frankliniella occidentalis的协同控害作用。室内测定结果表明, 绿僵菌孢子悬浮液浓度不大于5×107孢子/mL时, 不会对东亚小花蝽5龄若虫的存活和羽化造成负面影响。室内与温室笼罩条件下, 东亚小花蝽携带绿僵菌的处理能够降低辣椒上的西花蓟马和烟粉虱发生量, 表明东亚小花蝽携带绿僵菌可提高对西花蓟马和烟粉虱的防治效果, 证明了天敌昆虫和生防菌联合应用的可行性, 为生物防治方式多元化应用与推广提供了实践指导。  相似文献   

16.
Ophiostoma novo‐ulmi, the cause of the current pandemic of Dutch elm disease, is considered one of the 20 worst pests to have been introduced to New Zealand. An attempt to eradicate the pathogen came close to success, but was eventually stopped and replaced by management programmes. These programmes are slowing the spread of the pathogen. If left uncontrolled it is likely that New Zealand will lose 90% of its elm trees. Although elms are exotic trees in New Zealand, the loss of such a large number of popular amenity trees is likely to have numerous social, cultural, environmental and economic effects. It is estimated that this disease could cost public and councils over NZD $350 million in tree removal and replacement costs. Control of O. novo‐ulmi is limited, but biological control using d‐factor viruses has been proposed. Although O. novo‐ulmi was not eradicated from New Zealand, the eradication programme had many successes; in particular, the effective interaction of good management and science in the early years of the campaign. Also highlighted in this review are several tactics and steps that could be applied to eradication attempts for other species.  相似文献   

17.
ABSTRACT Transmission of Tomato spotted wilt virus (TSWV) is dependent on virus uptake in the midgut prior to virus movement to the salivary glands. Replication of TSWV in the alimentary canal of tobacco thrips (TT, Frankliniella fusca) and western flower thrips (WFT, F. occidentalis) was investigated by immunolocalization of the nonstructural protein (NSs) encoded by the small RNA of TSWV and fluorescence microscopy. Analysis of cohorts during development from larva to adults following virus acquisition by first instar larva indicated that virus replication followed a specific time-course pattern in the foregut, regions of the midgut, salivary glands, and ligaments between the midgut and salivary glands. Initial virus replication occurred only in epithelial cells of midgut-1 but, upon infection of muscle cells, the virus moved to the midgut-2, foregut, midgut-3, and salivary glands. The ligaments between the midgut and salivary glands appeared to be a route for virus to invade the salivary glands. No virus replication was observed in the hindgut, Malpighian tubules, or tubular salivary glands. The dynamics of TSWV replication, as measured by NSs accumulation, were similar in both TT and WFT.  相似文献   

18.
DAS-ELISA proved to be reliable enough to detect a latent infection by Tomato spotted wilt virus (TSWV) in asymptomatic stock plants of chrysanthemum. A high density of Frankliniella occidentalis, the predominant vector, in the presence of latently infected stock plants resulted in a high incidence of disease in the chrysanthemum production field. The incidence of disease was low when the vector thrips were not abundant in spite of the presence of latently infected stock plants. These results suggest that an infestation of the vector thrips causes severe secondary spread of TSWV originating from latently infected stock plants in chrysanthemum production fields. Received 27 July 2001/ Accepted in revised form 27 November 2001  相似文献   

19.
ABSTRACT Spread of Tomato spotted wilt virus (TSWV) and population development of its vector Frankliniella occidentalis were studied on the pepper accessions CPRO-1 and Pikante Reuzen, which are resistant and susceptible to thrips, respectively. Viruliferous thrips were released on plants of each accession (nonchoice tests) or on plants in a 1:1 mixture of both accessions (choice tests) in small cages containing 8 or 16 plants. Significantly fewer CPRO-1 plants became infected in the primary infection phase in both tests. In the nonchoice test, virus infection of the resistant plants did not increase after the initial infection, but all plants eventually became infected when mixtures of both cultivars were challenged in the secondary infection phase. Secondary spread of TSWV from an infected resistant or susceptible source plant was significantly slower to resistant plants than to susceptible plants, independent of source plant phenotype. The restricted introduction and spread of TSWV in the thrips-resistant cultivar was confirmed in a large-scale greenhouse experiment. The restricted and delayed TSWV spread to plants of the resistant accession in both the cage and the greenhouse experiment was explained by impeded thrips population development. The results obtained indicate that thrips resistance may provide a significant protection to TSWV infection, even when the crop is fully susceptible to the virus.  相似文献   

20.
为比较西花蓟马Frankliniella occidentalis对不同寄主植物的选择性,本研究采用罩笼法观察了西花蓟马对8种不同蔬菜寄主植物(茄子、甘蓝、辣椒、黄瓜、莴笋、番茄、芹菜、香菜)的选择性,并使用“Y”形嗅觉仪评价了西花蓟马对不同蔬菜的嗅觉行为反应。结果表明,在8种不同蔬菜寄主植物中,西花蓟马对茄子、甘蓝的选择性最高;对芹菜和香菜的选择性较弱,表明西花蓟马对芹菜和香菜表现出忌避性。本研究结果为了解西花蓟马对不同寄主植物的选择提供理论依据。  相似文献   

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