Short Report Virus Vector Species of Xiphinema and Longidorus in Relation to Certification Schemes for Fruit and Hops in England

1975 ◽  
pp. 283-285 ◽  
Author(s):  
J. Cotten
Keyword(s):  
Virus Vector ◽  
Short Report ◽  
Vector Species

scholarly journals Mealybug Transmission of Grapevine Leafroll Viruses: An Analysis of Virus–Vector Specificity

2010 ◽  
Vol 100 (8) ◽  
pp. 830-834 ◽  
Author(s):  
Chi-Wei Tsai ◽  
Adib Rowhani ◽  
Deborah A. Golino ◽  
Kent M. Daane ◽  
Rodrigo P. P. Almeida
Keyword(s):  
Plant Pathogens ◽  
Phylogenetic Analyses ◽  
Virus Vector ◽  
Disease Spread ◽  
Virus Species ◽  
Vector Species ◽  
Vector Transmission ◽  
Planococcus Ficus ◽  
Grapevine Leafroll Disease ◽  
Leafroll Disease

To understand ecological factors mediating the spread of insect-borne plant pathogens, vector species for these pathogens need to be identified. Grapevine leafroll disease is caused by a complex of phylogenetically related closteroviruses, some of which are transmitted by insect vectors; however, the specificities of these complex virus–vector interactions are poorly understood thus far. Through biological assays and phylogenetic analyses, we studied the role of vector-pathogen specificity in the transmission of several grapevine leafroll-associated viruses (GLRaVs) by their mealybug vectors. Using plants with multiple virus infections, several virus species were screened for vector transmission by the mealybug species Planococcus ficus and Pseudococcus longispinus. We report that two GLRaVs (-4 and -9), for which no vector transmission evidence was available, are mealybug-borne. The analyses performed indicated no evidence of mealybug–GLRaV specificity; for example, different vector species transmitted GLRaV-3 and one vector species, Planococcus ficus, transmitted five GLRaVs. Based on available data, there is no compelling evidence of vector–virus specificity in the mealybug transmission of GLRaVs. However, more studies aimed at increasing the number of mealybug species tested as vectors of different GLRaVs are necessary. This is especially important given the increasing importance of grapevine leafroll disease spread by mealybugs in vineyards worldwide.

scholarly journals A Single Amino Acid Position in the Helper Component of Cauliflower Mosaic Virus Can Change the Spectrum of Transmitting Vector Species

2005 ◽  
Vol 79 (21) ◽  
pp. 13587-13593 ◽  
Author(s):  
Aranzazu Moreno ◽  
Eugénie Hébrard ◽  
Marilyne Uzest ◽  
Stéphane Blanc ◽  
Alberto Fereres
Keyword(s):  
Amino Acid ◽  
Mosaic Virus ◽  
Amino Acid Position ◽  
Plant Viruses ◽  
Aphid Species ◽  
Virus Vector ◽  
Cauliflower Mosaic Virus ◽  
Vector Species ◽  
Helper Component ◽  
Mode Of Transmission

ABSTRACT Viruses frequently use insect vectors to effect rapid spread through host populations. In plant viruses, vector transmission is the major mode of transmission, used by nearly 80% of species described to date. Despite the importance of this phenomenon in epidemiology, the specificity of the virus-vector relationship is poorly understood at both the molecular and the evolutionary level, and very limited data are available on the precise viral protein motifs that control specificity. Here, using the aphid-transmitted Cauliflower mosaic virus (CaMV) as a biological model, we confirm that the “noncirculative” mode of transmission dominant in plant viruses (designated “mechanical vector transmission” in animal viruses) involves extremely specific virus-vector recognition, and we identify an amino acid position in the “helper component” (HC) protein of CaMV involved in such recognition. Site-directed mutagenesis revealed that changing the residue at this position can differentially affect transmission rates obtained with various aphid species, thus modifying the spectrum of vector species for CaMV. Most interestingly, in a virus line transmitted by a single vector species, we observed the rapid appearance of a spontaneous mutant specifically losing its transmissibility by another aphid species. Hence, in addition to the first identification of an HC motif directly involved in specific vector recognition, we demonstrate that change of a virus to a different vector species requires only a single mutation and can occur rapidly and spontaneously.

A comparison of the effectiveness of the four British virus vector species of Longidorus and Xiphinema

1981 ◽  
Vol 99 (1) ◽  
pp. 63-70 ◽  
Author(s):  
D. L. TRUDGILL ◽  
D. J. F. BROWN ◽  
W. M. ROBERTSON
Keyword(s):  
Virus Vector ◽  
Vector Species

scholarly journals Longidoridae and nepoviruses in Bulgaria and Slovenia

2012 ◽  
Vol 49 (1) ◽  
pp. 49-56 ◽  
Author(s):  
V. Peneva ◽  
G. Urek ◽  
S. Lazarova ◽  
S. Širca ◽  
M. Knapič ◽  
...  
Keyword(s):  
Virus Vector ◽  
Grapevine Fanleaf Virus ◽  
Vector Species ◽  
Slovenian Population ◽  
Bait Plants ◽  
Evident Relationship

AbstractData on the distribution of Longidoridae and nepoviruses in Bulgaria and Slovenia are summarized. Six species of Longidorus (L. apulus, L. attenuatus, L. arthensis, L. fasciatus, L. elongatus, L. macrosoma), one Paralongidorus species (P. maximus) and three Xiphinema species (X. diversicaudatum, X. index, X. rivesi) are known as natural vectors of nine nepoviruses in Europe. Currently, 10 and 13 species of Xiphinema; 6 and 15 of Longidorus are reported to occur in Slovenia and Bulgaria, respectively. Paralongidorus maximus has been reported only in Bulgaria. Among the virus vector species X. index, X. diversicaudatum and L. elongatus occur in both countries, X. rivesi only in Slovenia and L. attenuatus, L. macrosoma, X. italiae and P. maximus only in Bulgaria. A report of X. index and Grapevine fanleaf virus (GFLV) in Bulgaria was related to transgenic grape tolerance to the same virus. Nepoviruses have been reported from Slovenia, but despite an evident relationship in the occurrence of GFLV and X. index in several vineyards the only laboratory proven transmission is that of TRSV and ToRSV to bait plants by a Slovenian population of X. rivesi.

Identification of a novel bluetongue virus vector species of Culicoides in Sicily

2003 ◽  
Vol 153 (3) ◽  
pp. 71-74 ◽  
Author(s):  
S. Caracappa ◽  
A. Torina ◽  
A. Guercio ◽  
F. Vitale ◽  
A. Calabro ◽  
...  
Keyword(s):  
Bluetongue Virus ◽  
Virus Vector ◽  
Vector Species

The ultrastructure of the feeding apparatus and pharyngeal tract of four European species of Trichodoridae (Nematoda: Triplonchida)

Nematology ◽  
2004 ◽  
Vol 6 (5) ◽  
pp. 695-713 ◽  
Author(s):  
Eirini Karanastasi ◽  
Wilfrida Decraemer ◽  
Urs Wyss ◽  
Derek Brown
Keyword(s):  
Virus Vector ◽  
Root Cell ◽  
Feeding Apparatus ◽  
Vector Species ◽  
European Species ◽  
Particle Retention ◽  
First Time ◽  
New Evidence ◽  
Plant Parasitic

AbstractVirus-vector plant-parasitic Paratrichodorus and Trichodorus nematodes acquire Tobravirus particles whilst ingesting root cell sap from virus-infected plants and these particles are specifically retained by being adsorbed on to the cuticle lining the wall of the nematode pharyngeal lumen. The feeding apparatus and pharyngeal ultrastructure of four trichodorid virus-vector species were examined to identify the occurrence of any structural characters that could account for particle retention at specific sites in this region. Similarities between Paratrichodorus and Trichodorus species are reported for the first time and new evidence is provided on the position of all gland sinuses and outlets. The occurrence of an inner spear in adult specimens is discussed.

Acquisition of EELS spectra for high-resolution spectroscopy

1993 ◽  
Vol 51 ◽  
pp. 578-579
Author(s):  
Maoxu Qian ◽  
Mehmet Sarikaya ◽  
Edward A. Stern
Keyword(s):  
Energy Loss ◽  
Detection System ◽  
High Resolution Spectroscopy ◽  
High Signal ◽  
Short Report ◽  
Edge Structure ◽  
High Background ◽  
Gain Variation ◽  
Sufficient Energy ◽  
On Line

It is difficult, in general, to perform quantitative EELS to determine, for example, relative or absolute compositions of elements with relatively high atomic numbers (using, e.g., K edge energies from 500 eV to 2000 eV), to study ELNES (energy loss near edge structure) signal using the white lines to determine oxidation states, and to analyze EXELFS (extended energy loss fine structure) to study short range ordering. In all these cases, it is essential to have high signal-to-noise (S/N) ratio (low systematical error) with high overall counts, and sufficient energy resolution (∽ 1 eV), requirements which are, in general, difficult to attain. The reason is mainly due to three important inherent limitations in spectrum acquisition with EELS in the TEM. These are (i) large intrinsic background in EELS spectra, (ii) channel-to-channel gain variation (CCGV) in the parallel detection system, and (iii) difficulties in obtaining statistically high total counts (∽106) per channel (CH). Except the high background in the EELS spectrum, the last two limitations may be circumvented, and the S/N ratio may be attained by the improvement in the on-line acquisition procedures. This short report addresses such procedures.

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