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1.
This paper reviews the contribution of vector activity and plant age to virus spread in potato crops. Determining which aphid species are vectors is particularly important for timing haulm destruction to minimize tuber infection by potato virus Y (PVY). Alate aphids of more than 30 species transmit PVY, and aphids such asRhopalosiphum padi, that migrate in large numbers before flights of the more efficient vector,Myzus persicae, appear to be important vectors. Differences in methodology, aphid biotypes and virus strains prevent direct comparisons between estimates of vector efficiencies obtained for aphids in different countries in north western Europe.M. persicae is also the most efficient vector of potato leafroll virus (PLRV), but some clones ofMacrosiphum euphorbiae transmit PLRV efficiently toNicotiana clevelandii and potato test plants. The removal of infected plants early in the season prevents the spread of PLRV in cool regions with limited vector activity. The proportion of aphids acquiring PLRV from infected potato plants decreases with plant age, and healthy potato plants are more resistant to infection later in the season. Severe symptoms of secondary leafroll developed on progeny plants of cv. Maris Piper derived from mother plants inoculated with PLRV in June or July of the previous year. Progeny plants derived from mother plants inoculated in August showed only mild symptoms, but the concentration of PLRV in these plants was as high as that in the plants with severe symptoms.  相似文献   

2.
The influence of co‐infection on concentration and accumulation of genetically different isolates of Potato virus Y (PVY) in potato and tobacco plants and the efficiency of transmission by Myzus persicae of PVY isolates from doubly versus singly infected plants were evaluated. The vector ability to simultaneously transmit two virus isolates was examined. Eight PVY isolates represented three strain groups: PVYO (pathotype and serotype O), PVYNW (pathotype N and serotype O), and PVYNTN (pathotype and serotype N). Different diagnostic methods, including DAS‐ELISA, multiplex RT‐PCR, aphid transmission tests and bioassays, were applied to detect the presence of PVY isolates in source and assay plants. Significant reductions in concentrations of certain PVY isolates during co‐infection with other isolates were found both in potato and tobacco plants. The observed effects were both isolate‐ and host‐dependent in form. The highest rates of virus transmission by single aphids were recorded with PVYNTN isolates, and the lowest ones with PVYO isolates. Individual aphids of M. persicae were able to simultaneously transmit two PVY isolates. The frequency of transmission was generally low, but it reached as high as 20% for one of the isolate combinations. The findings presented in the work provide proof for antagonistic within‐plant interactions between isolates of PVY, with some implications of these interactions for virus transmission by aphid vectors. Consequently, this research contributes to a better understanding of the epidemiology of the disease caused by PVY.  相似文献   

3.
Potato virus Y (PVY) causes great economic losses in potato production world-wide. Concerning important it has replaced Potato leafroll virus (PLRV). Virus is transmitted by different aphid species in a non-persistent manner. During last years the developing of new effective methods for PVY monitoring, forecasting and detection in aphids is of increasing interest. Sensitive, rapid detection of virus in its natural vectors is of a great need to investigate the relationship between aphid migration and the spread of PVY. Simple diagnostic protocol for the detection of non-persistent Plum pox virus and semipersistent Citrus tristeza virus in aphids, proposed by Olmos et al. (2005) was probed to validate and estimate the efficiency of its applying for the detection of PVY in different aphid species too.  相似文献   

4.
Two different aphid species,Myzus persicae (Sulzer) andHyalopterus pruni (Geoffroy) (Homoptera: Aphididae), were used to analyze their ability to transmit two different potyviruses,Potato virus Y (PVY) andPlum pox virus (PPV), to pepper (Capsicum annuum) andNicotiana benthamiana plants, respectively. In parallel experiments,M. persicae consistently transmitted both viruses with high efficiency, whereasH. pruni always failed to transmit either virus. This is in contrast to previous reports describingH. pruni as a vector of these potyviruses. Different aphid probing behavior among individual aphids of each species was obtained in electrical penetration graph (EPG) experiments performed on pepper plants. This suggested thatH. pruni did not transmit these potyviruses due to behavioral differences during probing that impeded virus acquisition and/or inoculation. It was found thatM. persicae usually makes its first probe within the first 2 min, whereasH. pruni individuals remained for more than 10 min on the plant before starting to probe. Furthermore,M. persicae individuals displayed their first intracellular puncture during the first minute of probing whereasH. pruni needed ∼ 15 min to penetrate the cell plasmalemma with their stylets. In addition, intracellular stylet punctures occurred very frequently forM. persicae but was a rare event, never exceeding a single one, forH. pruni. The relevance of these findings for the epidemiological spread of potyviruses by different aphid species is discussed. http://www.phytoparasitica.org posting May 14, 2006.  相似文献   

5.
Host plant selection by aphids can be positively or negatively affected when plants are infected by phytoviruses. Potato plants infected by Potato virus Y (PVY), a non-persistent virus, are reported to affect settling behaviour and growth parameters of Myzus persicae Sulzer and Macrosiphum euphorbiae Thomas. Using the Electrical penetration graph system (EPG), we demonstrated that PVY-infection of potato plants influences the feeding behaviour of these two aphid species. Myzus persicae exhibited increased phloem sap ingestion and reduced non-probing duration. Macrosiphum euphorbiae showed delayed stylet insertion, reduced activity in the phloem vessels and an enhanced non-probing duration. In addition, we showed that these two species exhibited different transmission rates. The opposite effects of PVY-infected potato plant on these two aphids are discussed in terms of PVY spreading in the field.  相似文献   

6.
When ‘Bintje’ potato plants were inoculated mechanically with potato virus YN (PVYN),Myzus persicae acquired PVYN from both the inoculated and non-inoculated leaves about one week earlier than when plants were inoculated byM. persicae. Only when young plants of about four weeks after planting were inoculated byM. persicae, this aphid acquired PVYN from the non-inoculated top leaves within a fortnight. When plants later than four weeks after planting were inoculated byM. persicae it generally took at least four weeks for this aphid to acquire PVYN from non-inoculated top and other leaves of such plants. A number of leaves situated on the potato stems near to the inoculated ones did not serve as a PVYN-source forM. persicae within the experimental period of 38 days. The results indicate that it is possible that in seed potato growing areas primarily infected PVYN-infected plants, not yet showing symptoms, can act as virus sources for further spread. This is especially true in the beginning of the season.  相似文献   

7.
In the context of an epidemiological study on Potato virus Y (PVY) in potato crops, Solanum elaeagnifolium Cav. was included in the weeds prospected. Surveys were carried out in four seed potato areas: Cap Bon, Manouba, Jendouba and Kairouan. S. elaeagnifolium was found in all areas, except Cap Bon. Virus‐like symptoms were observed on some S. elaeagnifolium plants in the field, i.e. leaf mottling and curling. Aphids were collected on these plants and were identified as Myzus persicae and Aphis fabae, both known to colonize potatoes and to transmit the standard PVYN isolate with transmission efficiencies of 95% and 43%, respectively. Forty‐seven plant samples were tested with ELISA for the presence of PVY. Positive reactions were obtained from 2/6, 5/18, 8/23 samples collected in Manouba, Jendouba and Kairouan, respectively. Virus transmission was carried out using M. persicae as vector from two samples of each region onto plantlets of Nicotiana tabacum cv Xanthi. All inoculated plantlets displayed typical symptoms of the PVYN strain group, confirmed by serological testing using specific antibodies. This is the first report of a PVY natural infection on S. elaeagnifolium in Tunisia. The abundance of this weed, its over‐wintering status and the high rate of PVY‐infected plants (31.9%) allow us to deduce that S. elaeagnifolium must be considered a reservoir species of PVY under natural conditions in Tunisia and probably in other Mediterranean countries. The presence of efficient aphid vectors of PVY on this weed in crops is additional evidence that S. elaeagnifolium may become a problem by acting as a source plant for PVY spread in potato crops.  相似文献   

8.
Hairy nightshade, Solanum sarrachoides, is a solanaceous weed found abundantly in Pacific Northwest potato ecosystems. It serves as a reservoir for one of the important potato viruses, Potato leafroll virus (PLRV) (Luteoviridae: Polerovirus), and its most important vector, the green peach aphid, Myzus persicae (Homoptera: Aphididae). Laboratory research indicated an increased green peach aphid settling and performance on S. sarrachoides than on potato. It also revealed that green peach aphids transmitted PLRV more efficiently from S. sarrachoides to potato than from potato to potato. To test the efficiency of S. sarrachoides as an inoculum source in the field, a two season (2004 and 2005) trial was conducted at Kimberly, Idaho. Two inoculum sources, PLRV-infected potato and PLRV-infected S. sarrachoides, were compared in this trial. Green peach aphid density and temporal and spatial PLRV spread were monitored at weekly intervals. Higher densities of green peach aphids were observed on plots with S. sarrachoides and inoculum sources (PLRV-infected S. sarrachoides and potato) than on plots without S. sarrachoides and inoculum sources. PLRV infection in plots with PLRV-infected S. sarrachoides was similar to or slightly higher than in plots with PLRV-infected potato as an inoculum source. Temporal and spatial PLRV spread was similar in plots with either inoculum source. Thus, S. sarrachoides is as efficient as or a better PLRV inoculum source than potato.  相似文献   

9.
Since potato leafroll virus multiplies in the green peach aphid,Myzus persicae, the effect of the virus on the biology of its vector was investigated. Observations were made regarding the longevity and the reproduction rate of viruliferous and non-viruliferous aphids on leafroll-diseased and healthy plants ofPhysalis floridana. The same matters were investigated for both viruliferous and non-viruliferous aphids on seedlings of Chinese cabbage (Brassica pekinensis). It was shown that on leafroll-diseased plants ofP. floridana the aphids produced more progeny than on healthy ones, although the average number of progeny produced per day in both cases was almost the same. On healthy Chinese cabbage seedlings there was no difference in average length of the larval and adult stages, number of progeny per aphid, and number of progeny per day, between viruliferous and non-viruliferous aphids. Evidence was obtained that the virus does not influence the development of its vector. Measurements of oxygen consumption of both viruliferous and non-viruliferous aphids point in the same direction.  相似文献   

10.
为探究黄瓜花叶病毒(Cucumber mosaic virus,CMV)、马铃薯Y病毒(Potato virus Y,PVY)混合侵染烟株对烟蚜取食行为的影响,利用刺探电位图谱(electrical penetration graph,EPG)技术记录了烟蚜在健康烟株与CMV、PVY混合侵染后不同发病级别烟株上的取食波形。结果显示:烟蚜在健康烟株上的刺探次数最少,在感病烟株上的C波总持续时间均显著长于健康烟株;第1次到达韧皮部前的刺探次数,健康植株上仅为4.00次,3级感病烟株上的为健康烟株上的2倍;在健康烟株上E2波总持续时间为120.65 min,极显著大于2级和3级感病烟株;刺探过程中,感病烟株上的pd波出现次数均高于健康烟株,且pd波II-1和II-3亚波的持续时间也显著高于健康烟株。研究表明,CMV、PVY混合侵染烟株可降低寄主对烟蚜的适合度,且能促进烟蚜对病毒的传播。  相似文献   

11.
Potato leafroll virus (PLRV) antigen was localized by immunogold labelling in semi-thin leaf sections of secondarily-infected potato plants cv. Bintje. Viral antigen was present in all cell types of the phloem tissue. but occurred most abundantly in the companion cells. Detectable amounts of PLRV antigen were found only in the sieve elements in veins with a large number of infected companion cells. Occasionally, parenchyma cells were also found to be infected. PLRV was not exclusively limited to the phloem tissue in the infected potato plants, but was also found in mesophyll cells neighbouring minor phloem vessles. Spread of virus from cell to cell in the mesophyll was not observed. The distribution of PLRV in the potato leaf tissue has implication on its availability, for acquisition by aphids.  相似文献   

12.
利用RNA干扰介导抗病性获得兼抗四种病毒的转基因马铃薯   总被引：1，自引：1，他引：0  
为获得兼抗马铃薯X病毒(Potato virus X,PVX)、马铃薯Y病毒(Potato virus Y,PVY)、马铃薯卷叶病毒(Potato leaf roll virus,PLRV)和马铃薯潜隐花叶病毒(Potato virus S,PVS)4种病毒的转基因马铃薯新材料,分别以这4种病毒全长CP基因为模板,通过设计PCR引物和亚克隆获得4种病毒CP基因相对保守区段的基因片段,并将其拼接成融合基因,以载体pHANNIBAL和pBI121为基础,构建RNA干扰(RNA interference,RNAi)载体,利用农杆菌介导的转基因体系进行马铃薯遗传转化,并对获得的转基因马铃薯进行病毒抗性检测。结果表明,所获得的融合基因片段RH1和RH2,酶切鉴定分别得到长度为1 200 bp的条带,与预期片段相符;构建了含pdk内含子和RH1、RH2融合基因的RNAi植物表达载体,经Bam H I/Sac I双酶切,获得长度约3 200 bp的片段,表明RNAi植物表达载体pBI121-pRH构建成功;转化易感病毒马铃薯品种陇薯11号,PCR检测和PCRSouthern杂交分析表明融合基因已整合到陇薯11号马铃薯基因组中;抗病性检测显示4株转基因马铃薯植株对4种病毒均免疫。表明利用RNAi可筛选出抗多种病毒的转基因马铃薯新种质。  相似文献   

13.
Surveys were conducted of symptomatic potato plants in late season crops, from the major potato production regions in Northern Tunisia, for infection with six common potato viruses. The presence of Potato leafroll virus (PLRV), Potato virus Y (PVY), Potato virus X (PVX), Potato virus A (PVA), Potato virus S (PVS) and Potato virus M (PVM) was confirmed serologically with virus infection levels up to 5.4, 90.2, 4.3, 3.8, 7.1 and 4.8%, respectively. As PVY was prevalent in all seven surveyed regions, further biological, serological and molecular typing of 32 PVY isolates was undertaken. Only one isolate was shown to induce PVYO-type symptoms following transmission to tobacco and to react only against anti-PVYO-C antibodies. Typical vein necrosis symptoms were obtained from 31 samples, six of which reacted against both anti-PVYN and anti-PVYO-C antibodies showing they contained mixed isolates, while 25 of them reacted only with anti-PVYN antibodies. An immunocapture RT-PCR molecular test using a PVYNTN specific primer pair set in the 5’NTR/P1 genomic region and examination of recombinant points in three genomic regions (HC-Pro/P3, CI/NIa and CP/3’NTR) showed that all 25 serotype-N PVY isolates were PVYNTN variants with similar recombinations to the standard PVYNTN-H isolate. This is the first report of the occurrence of the PVYNTN variant and its high incidence in late season potatoes in Tunisia.  相似文献   

14.
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15.
Potato virus Y and many other viruses of potatoes cause major economic losses to seed potato production in many countries. Potato virus Y, which is transmitted in a non-persistent manner, is one of the most important virus diseases of potatoes in many countries in Europe and especially in the northern regions.During the last decade there has been an increasing interest in developing methods for potato virus forecasting. The abundance of virus vectors is often estimated by yellow water traps (YWT), suction traps or field surveys. In Sweden the relationship between occurrence of alate aphids and the proportion of PVY infected progeny tubers has been studied since 1975. A dynamic simulation model for PVY has been designed for predicting the incidence of PVY. The simulation model describes a system which includes e.g., healthy and PVY diseased potato plants, different aphid species as virus vectors an their efficiency as virus vectors, the susceptibility of the potato crop according to mature plant resistance and date of haulm destruction. There was a good correlation between model output and samples of progeny tubers tested for PVY.  相似文献   

16.
Potato virus Y (PVY) is responsible for major viral diseases in most potato seed areas. It is transmitted by aphids in a non-persistent manner, and it is spread in potato fields by the winged aphids flying from an infected source plant to a healthy one. Six different PVY strains groups affect potato crops: PVYC, PVYN, PVYO, PVYN:O, PVYNTN, and PVYN-Wi. Nowadays, PVYNTN and PVYN-Wi are the predominant strains in Europe and the USA. After the infection of the leaf and accumulation of the virus, the virus is translocated to the progeny tubers. It is known that PVYN is better translocated than PVYO, but little is known about the translocation of the other PVY strains. The translocation of PVY occurs faster in young plants than in old plants; this mature plant resistance is generally explained by a restriction of the cell-to-cell movement of the virus in the leaves. The mother tuber may play an important role in explaining mature plant resistance. PVY is able to pass from one stem to the other stems of the same plant through the vascular system of the mother tuber, but it is unknown whether this vascular link between stems is permanent during the whole life of the plant. Two greenhouse trials were set up to study the spread of PVY in the vascular system of the potato plant. The PVY-susceptible cultivar Charlotte was used for both trials. It was demonstrated that all stems growing from a PVY-infected tuber will become infected sooner or later, and that PVYN-Wi translocates more efficiently to progeny tubers than PVYNTN. It was also demonstrated that the progressive decay of the mother tuber in the soil reduces the possibility for virus particles to infect healthy stems through the vascular system of the mother tuber. This new element contributes to a better understanding of the mechanism of mature plant resistance.  相似文献   

17.
Summary Dijkstra (1933) demonstrated thatSolanum dulcamara (Bittersweet, Woody Nightshade) can be a host plant of potato leaf-roll virus. It was, however, not known whether this wild growing plant in nature contains the virus. AsS. dulcamara is the only common perennial Solanacea in the Netherlands its role as a virus reseroir was investigated.At 25 localities plants ofS. dulcamara were collected, and tested for the presence of leaf-roll virus by transferring virus-freeMyzus persicae (Sulz.) after 24 hrs feeding to groups ofPhysalis floridana, where they fed for 24 hrs before being killed. All plants ofS. dulcamara appeared to contain leafroll virus, though they did not show symptoms. Also seedlings ofS. dulcamara from seed of a leafroll infested plant showed no symptoms before or after infection with leafroll bij transmission withMyzus persicae (Sulz.).The virus could be transmitted fromS. dulcamara to potato (var. Bintje) byMyzus persicae (Sulz.) and by graftingS. dulcamara on potato.Seedlings, grown from seed obtained from a plant which was shown to have leaf-roll, all appeared to be infected with leaf-roll. As so far no plants were found or obtained which had no leaf-roll virus, it is possible that inS. dulcamara leaf-roll virus is invariably transmitted with seed. But as the virus does not appear to be pathogenic inS. dulcamara, one might assume that what in potatoes and other plants is called leaf-roll virus, inS. dulcamara is an integral, natural component of the organism.  相似文献   

18.
Field studies were conducted to assess the population and the spatial dynamics of the predatory bugMacrolophus costalis Fieber (Hemiptera: Miridae) and of its prey, the aphidMyzus persicae (Sulzer) (Hemiptera: Aphidoidea), on tobacco. From an untreated tobacco field in Tithorea (central Greece), tobacco leaves were collected from the upper and the lower half of the plants from June until September, in 1999 and 2000. The numbers ofM. costalis andM. persicae individuals per leaf were counted. Most aphids were observed during July and August (early and mid season), with densities dropping markedly in September. In contrast,M. costalis population densities increased late in the season (September). Significantly higher numbers of aphids were found on the upper half of the plants than on the lower half. In contrast, significantly moreM. costalis individuals were observed on the lower half. Iwao’s Regression Analysis was used in order to characterize the spatial pattern of the two species. According to this model, in both sampling seasons, aphids andM. costalis nymphs displayed an aggregated spatial pattern, whileM. costalis adults were found to be randomly distributed among sampling units. Although moreM. costalis individuals were recorded on leaves with relatively high aphid densities, this species did not react numerically to changes in prey density. In addition, a significant number of bugs were found on leaves with low aphid densities or no aphids at all. http://www.phytoparasitica.org posting Dec. 18, 2002.  相似文献   

19.
ABSTRACT Lepidopteran cells (Spodoptera frugiperda) produced isometric virus-like particles (VLP) when infected with a recombinant baculovirus Ac61 that contained the Potato leafroll virus (PLRV) coat protein gene modified with an N-terminal histidine tag (P3-6H). Cells infected with AcFL, a recombinant baculovirus that expressed cDNA copies of the PLRV genome RNA, did not produce virus-like particles (VLP). In cell lines doubly infected with Ac61 and AcFL, VLP were formed that contained PLRV-RNA packaged in P3-6H coat protein (FL). Both the P3-6H and the FL particles were morphologically indistinguishable from particles of PLRV despite the fact that they lacked the P5 readthrough protein present in wild-type PLRV. When aphids (Myzus persicae) were fed on, or injected with, purified PLRV, or VLP of either type (FL or P3-6H) and examined by electron microscopy, no differences were observed among treatments for particle endocytosis, transcellular transport, or exocytosis at the aphid midgut or accessory salivary glands. Particles were observed in the salivary canals and in the salivary duct leading out of the aphid. These results suggest that P5 readthrough protein of PLRV may not be essential for cellular transport of virus through aphid vectors.  相似文献   

20.
Potato leafroll virus (PLRV): its transmission and control   总被引：1，自引：0，他引：1  
This review provides a wide assessment of the present state of knowledge about the potato leafroll luteovirus (PLRV), a pathogen which is seriously devastating potato crops in many parts of the world. The main biological, physical and chemical properties of this virus are described. The transmission of PLRV by aphids, which are the only transmitters of this virus under natural conditions, is characterized. Special attention is given to the control of PLRV through the use of resistant potato cultivars. Recent advances in obtaining resistant transgenic plants are outlined.  相似文献   

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