scholarly journals The Effect of Aphid Vector Population Composition on Local and Background Components of Citrus Tristeza Virus Spread

2000 ◽  
Vol 14 (14) ◽  
Author(s):  
T. R. Gottwald ◽  
G. Gibson ◽  
S. M. Garnsey ◽  
M. Irey
Keyword(s):  
Citrus Tristeza Virus ◽  
Virus Spread ◽  
Population Composition ◽  
Aphid Vector ◽  
Vector Population ◽  
Tristeza Virus ◽  
Citrus Tristeza

scholarly journals Examination of the Effect of Aphid Vector Population Composition on the Spatial Dynamics of Citrus Tristeza Virus Spread by Stochastic Modeling

1999 ◽  
Vol 89 (7) ◽  
pp. 603-608 ◽  
Author(s):  
T. R. Gottwald ◽  
G. J. Gibson ◽  
S. M. Garnsey ◽  
M. Irey
Keyword(s):  
Citrus Tristeza Virus ◽  
Nearest Neighbor ◽  
Disease Spread ◽  
Virus Spread ◽  
Population Composition ◽  
Inoculum Sources ◽  
Aphid Vector ◽  
Melon Aphid ◽  
Tristeza Virus ◽  
Citrus Tristeza

Aphid vector species population composition is known to affect the spatial patterns of citrus tristeza virus (CTV) and the changes in these patterns over time. However, the biological processes that are associated with virus spread have not been well defined. The spatiotemporal dynamics of CTV were examined using data collected from research plots in the Dominican Republic and Costa Rica, where the brown citrus aphid (BCA), Toxoptera citricida, was the predominant species, and in Florida, where the BCA was absent and the melon aphid, Aphis gossypii, was the predominant vector. Data were analyzed using a spatiotemporal stochastic model for disease spread, and parameter values were evaluated using Markov chain Monte Carlo stochastic integration methods. Where the melon aphid was the dominant species, the model parameter likelihood values supported the hypothesis that the disease was spread through a combination of random background transmission (transmission originating from inoculum sources outside the plot) and a local interaction (transmission from inoculum sources within the plot) operating over short distances. Conversely, when BCA was present, results often suggested a local short-range transmission interaction that was not restricted to nearest-neighbor interactions and that the presence of background infection was not necessary to explain the observations.

scholarly journals Spread of Citrus Tristeza Virus in Citrus Orchards in Central California

Plant Disease ◽  
2020 ◽  
Vol 104 (7) ◽  
pp. 1925-1931
Author(s):  
Raymond K. Yokomi ◽  
Mark S. Sisterson ◽  
Subhas Hajeri
Keyword(s):  
Citrus Tristeza Virus ◽  
Virus Spread ◽  
Central California ◽  
Aphid Control ◽  
Citrus Orchards ◽  
Individual Trees ◽  
Extension Center ◽  
Tristeza Virus ◽  
Tulare County ◽  
Citrus Tristeza

In California, citrus tristeza virus (CTV) is regulated by a State Interior Quarantine. In CTV abatement districts in central California, trees with CTV that react to MCA13 (MCA13-positive [MCA13+]), a strain-discriminating monoclonal antibody, are rogued to prevent virus spread. The Tulare County Pest Control District, however, does not participate in this abatement program except for a 1.6-km2 zone around the Lindcove Research and Extension Center, Exeter, CA. To quantify CTV spread under these two disparate management programs, CTV surveys were conducted in abatement plots with mandatory aphid control and nonabatement plots. Abatement plot surveys used hierarchical sampling of 25% of trees with samples pooled from four adjacent trees. Detection of MCA13+ CTV in a sample prompted resampling and testing of individual trees. From 2008 to 2018, incidence of CTV increased by an average of 3.9%, with only two MCA13+ samples detected. In contrast, in nonabatement plots, incidence of CTV increased by an average of 4.6% between 2015 and 2018. Increase in MCA13-negative (MCA−) isolates was 11 times greater than that of MCA13+ isolates, with the number of MCA13+ trees increasing by 19 trees between 2015 and 2018. MCA13− isolates were more randomly distributed, suggesting primary spread, whereas MCA13+ CTV isolates were more aggregated, suggesting some secondary spread. These results suggest that spread of MCA13+ isolates was limited by a combination of tree removal and aphid vector suppression. MCA13+ samples were VT isolates with some mixtures with T30 isolates. Despite the presence of VT isolates, all CTV-infected trees were asymptomatic.

scholarly journals Minor Coat and Heat Shock Proteins Are Involved in the Binding of Citrus Tristeza Virus to the Foregut of Its Aphid Vector, Toxoptera citricida

2016 ◽  
Vol 82 (21) ◽  
pp. 6294-6302 ◽  
Author(s):  
N. Killiny ◽  
S. J. Harper ◽  
S. Alfaress ◽  
C. El Mohtar ◽  
W. O. Dawson
Keyword(s):  
Heat Shock ◽  
Citrus Tristeza Virus ◽  
Viral Proteins ◽  
Aphid Vector ◽  
Toxoptera Citricida ◽  
Shock Proteins ◽  
Tristeza Virus ◽  
Minor Coat Protein ◽  
Citrus Tristeza

ABSTRACTVector transmission is a critical stage in the viral life cycle, yet for most plant viruses how they interact with their vector is unknown or is explained by analogy with previously described relatives. Here we examined the mechanism underlying the transmission of citrus tristeza virus (CTV) by its aphid vector,Toxoptera citricida, with the objective of identifying what virus-encoded proteins it uses to interact with the vector. Using fluorescently labeled virions, we demonstrated that CTV binds specifically to the lining of the cibarium of the aphid. Throughin vitrocompetitive binding assays between fluorescent virions and free viral proteins, we determined that the minor coat protein is involved in vector interaction. We also found that the presence of two heat shock-like proteins, p61 and p65, reduces virion bindingin vitro. Additionally, treating the dissected mouthparts with proteases did not affect the binding of CTV virions. In contrast, chitinase treatment reduced CTV binding to the foregut. Finally, competition with glucose,N-acetyl-β-d-glucosamine, chitobiose, and chitotriose reduced the binding. These findings together suggest that CTV binds to the sugar moieties of the cuticular surface of the aphid cibarium, and the binding involves the concerted activity of three virus-encoded proteins.IMPORTANCELimited information is known about the specific interactions between citrus tristeza virus and its aphid vectors. These interactions are important for the process of successful transmission. In this study, we localized the CTV retention site as the cibarium of the aphid foregut. Moreover, we demonstrated that the nature of these interactions is protein-carbohydrate binding. The viral proteins, including the minor coat protein and two heat shock proteins, bind to sugar moieties on the surface of the foregut. These findings will help in understanding the transmission mechanism of CTV by the aphid vector and may help in developing control strategies which interfere with the CTV binding to its insect vector to block the transmission.

First report of citrus tristeza virus in commercial citrus orchards in Tunisia

2021 ◽  
Author(s):  
Asma Najar ◽  
Imen Hamdi ◽  
Souad Mahmoud ◽  
Lassaad Medhioub ◽  
Imed Jaouadi ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
First Report ◽  
Citrus Orchards ◽  
Tristeza Virus ◽  
Citrus Tristeza

A model for the spread and control of citrus tristeza virus disease

1989 ◽  
Vol 16 (3) ◽  
pp. 315-320
Author(s):  
Ruth Marcus ◽  
Hovav Talpaz ◽  
Moshe Bar-Joseph
Keyword(s):  
Citrus Tristeza Virus ◽  
Virus Disease ◽  
And Control ◽  
Tristeza Virus ◽  
Citrus Tristeza

Sscp analysis of variations in haplotypes of citrus tristeza virus isolated from yuzu (Citrus junos) in geographically separate regions of Korea

2006 ◽  
Vol 49 (1) ◽  
pp. 88-96 ◽  
Author(s):  
Dae Hyun Kim ◽  
Hye Kyung Shim ◽  
Jae Wook Hyeon ◽  
Hyeog Mo Kwon ◽  
Kwang Sik Kim ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Sscp Analysis ◽  
Citrus Junos ◽  
Tristeza Virus ◽  
Citrus Tristeza

Production of Antibodies to Citrus Tristeza Virus in Transgenic Citrus

1995 ◽  
Author(s):  
Richard Lee ◽  
Moshe Bar-Joseph ◽  
K.S. Derrick ◽  
Aliza Vardi ◽  
Roland Brlansky ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Virus Disease ◽  
Biological Activities ◽  
Cp Gene ◽  
Single Domain Antibodies ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
Citrus Tristeza

Citrus tristeza virus (CTV) is the most important virus disease of citrus in the world. CTV causes death of trees on sour orange rootstock and/or stem pitting of scions regardless of rootstock which results in trees of low vigor, reduced yield with reduction in size and quality of fruit. The purpose of this project was to produce monoclonal antibodies (MABs) to CTV coat protein (CP), develop single domain antibodies (dAbs) or Fab fragments which neutralize the infection by binding to the virus, and to produce transformed plants which express the dAbs. The objectives of this research have been met and putative transgenic tobacco and citrus plants have been developed. These putative transgenic plants are presently undergoing evaluation to determine the level of dAbs expression and to determine their resistance to CTV. Additionally, the CTV genome has been sequenced and the CP gene of several biologically characterized CTV strains molecular characterized. This has indicated a correlation between CP sequence homology and biological activity, and the finding of DI RNAs associated with some CTV strains. Several MABs have been produced which enable broad spectrum identification of CTV strains while other MABs enable differentiation between mild and severe strains. The use of selected MAbs and determination of the CP gene sequence has enabled predictions of biological activities of unknown CTV isolates. The epitopes of two MABs, one reacting selectively with severe CTV strains and the other reacting with all strains, have been characterized at the molecular level.

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