Aphid stylet activities during potyvirus acquisition from plants and anin vitro system that correlate with subsequent transmission (original) (raw)
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Entomologia Experimentalis et Applicata, 1993
The effect of pre-acquisition starvation on stylet penetration behaviour by the aphid Myzus persicae (Sulz.) and the consequent non-persistent transmission of the potyviruses beet mosaic virus (BMV) and potato virus Y (PVY) were investigated. Visual observations indicated that starved aphids initiated penetrations earlier and penetrated for shorter periods than non-starved insects. Tethering with a fine gold wire did not affect these observations with either starved or non-starved aphids, but starvation caused increased PVY and BMV acquisition efficiency, regardless of tethering. Tethered aphids were then made part of an electrical circuit and their styler activities investigated in detail. Electrically recorded aphids also acquired and inoculated both potyviruses more efficiently when starved, and these acquisitions and inoculations were associated with stylet punctures of plant cell membranes. However, starvation did not affect the occurrence of electrically recorded membrane puncture, suggesting that non-behavioural factors may contribute to the enhancement of virus transmission by pre-acquisition starvation.
Journal of General Virology, 2012
Inoculation of the semi-persistent cauliflower mosaic virus (CaMV, genus Caulimovirus) is associated with successive brief (5-10 s) intracellular stylet punctures (pd) when aphids probe in epidermal and mesophyll cells. In contrast to non-persistent viruses, there is no evidence for which of the pd subphases (II-1, II-2 and II-3) is involved in the inoculation of CaMV. Experiments were conducted using the electrical penetration graph (EPG) technique to investigate what particular subphases of the pd are associated with the inoculation of CaMV to turnip by its aphid vector Brevicoryne brassicae. In addition, the same aphid species/test plant combination was used to compare the role of the pd subphases in the inoculation of the non-persistent turnip mosaic virus (TuMV, genus Potyvirus). Inoculation of TuMV was found to be related to subphase II-1, confirming earlier results, but CaMV inoculation appeared to be related exclusively to subphase II-2 instead. The mechanism of CaMV inoculation and the possible nature of subphase II-2 are discussed in the scope of our findings. %paper no. vir037887 charlesworth ref: vir037887& Plant
Journal of General Virology, 1996
The hypothesis that loss of aphid transmissibility of potyvirus mutants is due to non-retention of virions in the mouthparts was tested by feeding aphids through membranes on purified virions of aphid transmissible (AT or HAT) and non-aphid-transmissible (NAT) tobacco vein mottling virus (TVMV) or tobacco etch virus (TEV), in the presence of functional [potato virus Y (PVY) HC or TVMV HC] or non-functional (PVC HC) helper component (HC). TVMV virions were detected, by electron microscopic examination of immunogoldlabelled thin sections, in the food canal or cibarium of 57 % of 28 aphids fed on the transmissible combination of TVMV-AT and functional HC, while no virions were found in these structures in 25 aphids fed on the nontransmissible combinations: TVMV-NAT and PVY HC, or TVMV-AT and PVC HC. Autoradiography of intact stylets allowed the examination of much larger numbers of aphids, fed on 125I-labelled TEV; 48 % of 523 aphids fed on the TEV-HAT and PVY HC combination retained label in the stylets; this correlated well with the percentage transmission in bioassays. In contrast, in non-transmissible combinations, label was found in the stylets of 0.77% of 389 aphids fed on TEV-NAT and PVY HC, and 1-35 % of 223 aphids fed on TEV-HAT and PVC HC. No differences were found in the overall amount of label in the bodies of aphids fed on the transmissible and non-transmissible combinations.
Modification of Non-Vector Aphid Feeding Behavior on Virus-Infected Host Plant
Journal of Insect Science, 2013
Virus-infected host plants can have positive, neutral or negative effects on vector aphids. Even though the proportion of non-vector aphids associated with a plant far exceeds that of vector species, little is known about the effect of virus-infected plants on non-vector aphids. In the present study, the English grain aphid Sitobion avenae (Fabricius) (Hemiptera: Aphididae), a non-vector of Wheat dwarf virus (WDV) and Cereal yellow dwarf virus-RPV (CYDV-RPV), was monitored on, virus-infected, virus-free and leafhopper/aphid-infested, and virus-and insect-free (control) barley, Hordeum vulgare L. (Poales: Poaceae), plants. Electrical penetration graph recordings were performed. Compared with the control plants, S. avenae on infected plants exhibited reduced non-probing and pathway phase, and increased phloem sap ingestion phase, and more aphids reached sustained phloem ingestion. However, the electrical penetration graph parameters described above showed no significant differences in aphid feeding behavior on virus-free and vector pre-infested plants and the control barley plants during S. avenae feeding. The results suggest that WDV/CYDV-RPV-infected host plants positively affected the feeding behavior of the non-vector aphid S. avenae. Based on these results, the reasons and trends among the virusinfected host plants' effects on the feeding behavior of non-vector aphids are discussed.
Aphids as transport devices for plant viruses
Comptes Rendus Biologies, 2010
Plant viruses have evolved a wide array of strategies to ensure efficient transfer from one host to the next. Any organism feeding on infected plants and traveling between plants can potentially act as a virus transport device. Such organisms, designated vectors, are found among parasitic fungi, root nematodes and plant-feeding arthropods, particularly insects. Due to their extremely specialized feeding behavior – exploring and sampling all plant tissues, from the epidermis to the phloem and xylem – aphids are by far the most important vectors, transmitting nearly 30% of all plant virus species described to date. Several different interaction patterns have evolved between viruses and aphid vectors and, over the past century, a tremendous number of studies have provided details of the underlying mechanisms. This article presents an overview of the different types of virus-aphid relationships, state-of-the-art knowledge of the molecular processes underlying these interactions, and the remaining black boxes waiting to be opened in the near future.Les virus de plantes ont développé une grande diversité de stratégies pour assurer leur transmission efficace d’un hôte malade vers un nouvel hôte sain. Tout organisme se nourrissant sur une plante infectée, et capable de se déplacer vers d’autres plantes, peut potentiellement transporter des virus. De tels organismes sont dénommés « vecteurs » et se trouvent parmi les champignons phytopathogènes, les nématodes des racines, et les arthropodes, en particulier les insectes. Du fait de leur comportement alimentaire très particulier, explorant et échantillonnant différents tissus végétaux (épiderme, mésophylle et tissus vasculaires), les pucerons sont de loin les vecteurs de virus les plus performants, transmettant près de 30 % des espèces de virus de plantes décrites à ce jour. Plusieurs mécanismes d’interaction virus-puceron très différents ont évolué et, depuis plus d’un siècle, un effort de recherche très important a permis de les décortiquer, au moins pour certaines espèces virales modèles. Cet article présente une synthèse de ces connaissances, les trajets des virus dans leurs pucerons vecteurs, les mécanismes cellulaires et moléculaires de leurs interactions et les grandes inconnues qui persistent et qui devront être élucidées dans les années à venir.
Role of the helper component in vector-specific transmission of potyviruses
Journal of General Virology, 1998
Four aphid species were tested for their ability to transmit tobacco etch (TEV) and turnip mosaic (TuMV) potyviruses. Myzus persicae and Aphis gossypii transmitted both viruses efficiently from infected plants, whereas Lipaphis erysimi transmitted only TuMV and Myzus ascalonicus was a poor or non-transmitter of either virus. Similar electrically monitored probing patterns were produced by M. persicae, L. erysimi and M. ascalonicus, ruling out behavioural differences as the cause of differential transmission. Transmission results similar to those from infected plants were obtained when these aphids acquired homologous virus/helper component (HC) mixtures through membranes. Methods Aphids. Two species, Myzus persicae and Aphis gossypii, were chosen for their general efficacy as potyvirus vectors. In experiments at Lexington (KY, USA), M. persicae was reared on mustard (Brassica perviridis) and A. gossypii on cucumber (Cucumis sativus). Lipaphis erysimi and Myzus ascalonicus were chosen for their potential as differential vectors and were reared on mustard and pansy (Viola wittrockiana),
Annals of the Entomological Society of America, 2005
Caulißower mosaic virus (CaMV) is transmitted to crucifers in a noncirculative manner by several aphid species. CaMV is preferentially acquired from the phloem, although acquisition also occurs after brief intracellular stylet punctures of aphid vectors in nonvascular leaf tissues. In the present work, we used the electrical penetration graph technique to study the speciÞc aphid stylet activities and behavioral events leading to the inoculation of CaMV to turnip plants by its two major vectors, Brevicoryne brassicae (L.) and Myzus persicae (Sulzer). Aphids subjected to an 8-h acquisition access time on infected plants were transferred to test plants and removed immediately after speciÞc behavioral events were recorded. CaMV was readily inoculated after the Þrst intracellular puncture in nonvascular tissues by both vector species. Inoculation rate of CaMV by B. brassicae was the highest after a 3-h inoculation access period, regardless of whether aphids had reached the phloem phase during that period. Consistent interspeciÞc differences also were found in the ability of both aphid vectors to retain CaMV. B. brassicae could retain the virus after several intracellular punctures, whereas M. persicae readily lost the virus after performing the same number of intracellular stylet punctures. We concluded that salivation by aphids during successive intracellular stylet punctures in the epidermal and mesophyll cells before reaching the phloem phase are the key behavioral events associated to the inoculation of Caulißower mosaic virus. The likely location of the viral retention site inside the aphid mouthparts is discussed.
Aphids secrete watery saliva into plant tissues from the onset of stylet penetration
Entomologia Experimentalis et Applicata, 2011
Aphid feeding requires the secretion of two types of saliva: gelling saliva (from the principal gland) that forms an intercellular sheath for the penetrating stylet, and watery saliva [from accessory salivary glands (ASGs)] that facilitates intracellular penetration and phloem feeding. Plant viruses can be used as salivary markers to investigate key steps in aphid feeding, and penetration can be monitored electrically using the electrical penetration graph (EPG) approach. We conducted a series of EPG-controlled transmission experiments using Cucurbit aphid-borne yellows virus [CABYV; Polerovirus spec. (Luteoviridae)], which is retained in the ASGs, as a marker for watery saliva secretions. The melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), was used as a vector and melon seedlings, Cucumis melo L. (Cucurbitaceae), as host plants. Viruliferous aphids were interrupted at various stages during stylet penetration, i.e., during intercellular penetration prior to intracellular puncture and following a potential drop within the first probe. Viruliferous aphids and leaf disc samples obtained from the stylet penetration site were used to detect CABYV by quantitative real-time RT-PCR. Approximately half of the inoculated leaf discs were found to be infected with CABYV after very brief (12.9 ± 1.9 s) intercellular stylet probes and before intracellular stylet puncture. The number of virus particles ejected during such probes was similar to the number ejected by aphids during longer probes including a single intracellular puncture. Our results therefore suggest that watery saliva is secreted by aphids from the onset of stylet penetration.
Archives of Virology, 2019
Potato virus Y (PVY) is a common pathogen affecting agricultural production worldwide, and is mainly transmitted by Myzus persicae in a non-persistent manner. Insect-borne plant viruses can modify the abundance, performance, and behavior of their vectors by altering host plant features; however, most studies have overlooked the fact that the dynamic progression of virus infection in plants can have variable effects on their vectors. We addressed this point in the present study by dividing the PVY infection process in tobacco into three stages (early state, steady state and late state) according to viral copy number, and then compared the variational effects of PVY-infected tobacco (Nicotiana tabacum) plants on host selection and feeding behavior of M. persicae. A Y-shaped olfactory apparatus and electrical penetration graph (EPG) method were used to evaluate host selection and feeding behavior, respectively. Interestingly, we found that PVY-infected plants at the steady state of infection attracted more aphids than healthy plants, whereas no differences were observed for those at the early and late states. In terms of feeding behavior, intracellular punctures which are closely related to PVY acquisition and transmission were more abundant on PVY-infected tobacco plants at the early and steady states of infection than in non-infected plants. These results indicate that PVY-infected host plants can alter the host selection and feeding behavior of aphids in a stage-dependent manner manner, which is an important consideration when studying the interactions among host plants, virus, and insect vectors.
Ann Entomol Soc Amer, 2005
Caulißower mosaic virus (CaMV) is transmitted to crucifers in a noncirculative manner by several aphid species. CaMV is preferentially acquired from the phloem, although acquisition also occurs after brief intracellular stylet punctures of aphid vectors in nonvascular leaf tissues. In the present work, we used the electrical penetration graph technique to study the speciÞc aphid stylet activities and behavioral events leading to the inoculation of CaMV to turnip plants by its two major vectors, Brevicoryne brassicae (L.) and Myzus persicae (Sulzer). Aphids subjected to an 8-h acquisition access time on infected plants were transferred to test plants and removed immediately after speciÞc behavioral events were recorded. CaMV was readily inoculated after the Þrst intracellular puncture in nonvascular tissues by both vector species. Inoculation rate of CaMV by B. brassicae was the highest after a 3-h inoculation access period, regardless of whether aphids had reached the phloem phase during that period. Consistent interspeciÞc differences also were found in the ability of both aphid vectors to retain CaMV. B. brassicae could retain the virus after several intracellular punctures, whereas M. persicae readily lost the virus after performing the same number of intracellular stylet punctures. We concluded that salivation by aphids during successive intracellular stylet punctures in the epidermal and mesophyll cells before reaching the phloem phase are the key behavioral events associated to the inoculation of Caulißower mosaic virus. The likely location of the viral retention site inside the aphid mouthparts is discussed.