scholarly journals Impact of Mutations in Arabidopsis thaliana Metabolic Pathways on Polerovirus Accumulation, Aphid Performance, and Feeding Behavior

Viruses ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 146 ◽  
Author(s):  
Florent Bogaert ◽  
Aurélie Marmonier ◽  
Elodie Pichon ◽  
Sylvaine Boissinot ◽  
Véronique Ziegler-Graff ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Feeding Behavior ◽  
Metabolic Pathways ◽  
Transmission Rate ◽  
Virus Transmission ◽  
Virus Titer ◽  
Transmission Efficiency ◽  
Protein Amino Acid ◽  
Virus Acquisition ◽  
Turnip Yellows Virus

During the process of virus acquisition by aphids, plants respond to both the virus and the aphids by mobilizing different metabolic pathways. It is conceivable that the plant metabolic responses to both aggressors may be conducive to virus acquisition. To address this question, we analyze the accumulation of the phloem-limited polerovirus Turnip yellows virus (TuYV), which is strictly transmitted by aphids, and aphid’s life traits in six Arabidopsis thaliana mutants (xth33, ss3-2, nata1, myc234, quad, atr1D, and pad4-1). We observed that mutations affecting the carbohydrate metabolism, the synthesis of a non-protein amino acid and the glucosinolate pathway had an effect on TuYV accumulation. However, the virus titer did not correlate with the virus transmission efficiency. Some mutations in A. thaliana affect the aphid feeding behavior but often only in infected plants. The duration of the phloem sap ingestion phase, together with the time preceding the first sap ingestion, affect the virus transmission rate more than the virus titer did. Our results also show that the aphids reared on infected mutant plants had a reduced biomass regardless of the mutation and the duration of the sap ingestion phase.

scholarly journals Silver Nanoparticles as A Highly Viricidal Agent to Deter Plant-Infecting Viruses and Disrupt their Acquisition and Transmissibility by Vector Aphid

2021 ◽  
Author(s):  
Ahmed El Gamal ◽  
Mohamed Reda Tohamy ◽  
Mohamed Ibrahim Abou-Zaid ◽  
Mahmoud Mohamed Atia ◽  
Tarek El Sayed ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Plant Pathogens ◽  
Virus Transmission ◽  
Transmission Efficiency ◽  
Yellow Mosaic Virus ◽  
Virus Inoculation ◽  
Virus Acquisition ◽  
Disease Occurrence ◽  
Bean Plants ◽  
Pathogenesis Related Gene

Abstract Silver nanoparticles (AgNPs) are a potentially effective tool for deterring viral plant pathogens. This study was carried out to evaluate the efficacy of AgNPs to defeat Bean yellow mosaic virus (BYMV) on faba bean plants from the host, virus and vector aphid tripartite interactions side. The antiviral capabilities were evaluated during a foliar protective and curative scheme. Furthermore, the efficiency of AgNPs on virus acquisition and transmission by its vector aphid was investigated. Results indicated that the AgNPs had greatly exhibited curative viricidal activities for inactivation BYMV when applied 48 h post-virus inoculation. The disease occurrence was entirely inhibited with AgNPs rate as low as 100 mg.l− 1, while the infectivity was completely arrested when plants were preventively exposed to 200 mg.l− 1 24 h pre-virus inoculation. AgNPs proved high bio-reactivity by binding to viral particles, suppressing their replication and accumulation within the plant tissues. Moreover, it was noticeably showed to upregulate the pathogenesis-related gene (PR-1) and promote the defense-related enzymes and protein profiles in treated plants irrespective of concentration. Exposure of aphids to AgNPs-treated plants before virus acquisition excitingly reduced the BYMV acquisition and transmission efficiency by 40.65% up to 100 % 24 h post-application and the virus acquisition was affected for 10 days by 6.89 Up to 79.64 % depending on the AgNPs rate. These results concluded that the AgNPs have a high curing viricidal activity by targeting the virus envelop, and more excitingly it can affect the virus-vector combination, suggesting that it may contribute to alleviating the natural disease occurrence and virus transmission under field conditions. Therefore, according to the available literature, this study provides the first report on the deterring activity of nanomaterials against plant virus acquisition and transmission by its vector insects.

scholarly journals Feeding Behavior and Virus-transmission Ability of Insect Vectors Exposed to Systemic Insecticides

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 895 ◽  
Author(s):  
Elisa Garzo ◽  
Aránzazu Moreno ◽  
María Plaza ◽  
Alberto Fereres
Keyword(s):  
Feeding Behavior ◽  
Virus Transmission ◽  
Plant Viruses ◽  
Crop Damage ◽  
Insect Vectors ◽  
Vector Borne Diseases ◽  
Systemic Insecticides ◽  
Turnip Yellows Virus ◽  
Vector Borne ◽  
Leaf Curl Virus

The majority of plant viruses depend on Hemipteran vectors for their survival and spread. Effective management of these insect vectors is crucial to minimize the spread of vector-borne diseases, and to reduce crop damage. The aim of the present study was to evaluate the effect of various systemic insecticides on the feeding behavior of Bemisia tabaci and Myzus persicae, as well as their ability to interfere with the transmission of circulative viruses. The obtained results indicated that some systemic insecticides have antifeeding properties that disrupt virus transmission by their insect vectors. We found that some of the tested insecticides significantly reduced phloem contact and sap ingestion by aphids and whiteflies, activities that are closely linked to the transmission of phloem-limited viruses. These systemic insecticides may play an important role in reducing the primary and secondary spread of tomato yellow leaf curl virus (TYLCV) and turnip yellows virus (TuYV), transmitted by B. tabaci and M. persicae, respectively.

scholarly journals Titer Variation of Citrus Tristeza Virus in Aphids at Different Acquisition Access Periods and Its Association with Transmission Efficiency

Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 874-879
Author(s):  
Jinxiang Liu ◽  
Lingdi Li ◽  
Hengyan Zhao ◽  
Yan Zhou ◽  
Hongsu Wang ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Transmission Rate ◽  
Virus Titer ◽  
Transmission Efficiency ◽  
Pcr Assay ◽  
Toxoptera Citricida ◽  
The Mean ◽  
Green Fluorescent ◽  
Tristeza Virus ◽  
Citrus Tristeza

Tristeza, caused by citrus tristeza virus (CTV; Closterovirus, Closteroviridae), is of significant economic importance. Tristeza epidemics have caused severe declines in productivity, and even death, of millions of citrus trees on sour orange rootstock in many regions all over the world. In the field, CTV is most efficiently vectored by the brown citrus aphid (Toxoptera citricida (Kirkaldy)) in a semipersistent manner. The transmission efficiency of the vector is influenced by its acquisition access period (AAP) for CTV. A real-time RT-PCR assay using SYBR Green fluorescent dye was used to estimate the CTV titers in groups of 15 aphids under AAPs after 0.5 to 48 h for three CTV isolates (CT11A, CT16-2, and CTLJ). Similar trends for CTV titer in viruliferous aphids were displayed for the three isolates. The maximum CTV titer was at AAP 6 h for isolates CT11A and CT16-2, and at 4 h for isolate CTLJ. During the AAPs from 0.5 to 6 h, the mean CTV titer of CT16-2 increased from 7.8 × 104 to 1.71 × 107 copies per 15 aphids, and was correlated with an increase in transmission rate from 20 to 90.9%. This suggests that the transmission efficiency is positively correlated with viral titer in the insect from 0.5 h until 6 h AAPs. While a downward trend in CTV titer was observed after a 6-h AAP, the transmission rate remained higher than 90% up to 48 h. These results indicate that factors other than the virus titer in the vector contribute to successful transmission under long acquisition conditions. This is the first detailed quantitative analysis of CTV in its main vector species following different AAPs and its association with transmission efficiency, and should enhance our understanding of T. citricida-CTV interactions.

scholarly journals VARIATION IN RICE TUNGRO VIRUS TRANSMISSION ABILITY BY GREEN LEAFHOPPER, Nephotettix virescens DISTANT (HOMOPTERA: CICADELLIDAE) ON RICE RESISTANT VARIETIES

2013 ◽  
Vol 15 (2) ◽  
pp. 65
Author(s):  
I Nyoman Widiarta ◽  
Adolf Bastian ◽  
Syahrir Pakki
Keyword(s):  
Transmission Rate ◽  
Virus Transmission ◽  
Transmission Efficiency ◽  
Resistant Variety ◽  
Rice Varieties ◽  
Nephotettix Virescens ◽  
Green Leafhopper ◽  
Resistant Varieties ◽  
History Of ◽  
Efficient Vector

Green leafhopper (GLH), Nephotettix virescens, is the most efficient vector of rice tungro virus disease. The disease is endemic in some provinces of Indonesia and commonly con-trolled using resistant varieties. Resistance of rice varieties to tungro could be classified into resistance to a virus and a vector. The history of GLH resistant varieties adoption affected the GLH adaptation in an area. The study was conducted in the period of 2009-2011 to evaluate the resistance status of five GLH resistant rice variety groups (T0-T4) using survival and transmission test. The GLH populations were collected from 15 tungro endemic provinces in Indonesia. The GLH was then reared in the greenhouse before used for the test. The degree of resistance to tungro viruses was calculated by adding the value of survival (weight x score of survival rate) and virus transmission rate (weight x score of transmission rate). The weights for survival and transmission rate were set to 40 and 60, respectively. The results showed that the rank of resistant variety groups in decreasing order of resistance were T4, T1, T2 and T3. Five variations in GLH transmission efficiency were identified, i.e. 170, 070, 050, 030 and 010. GLH populations from Bali and West Nusa Tenggara were the most efficient vector for rice tungro virus. We concluded that there were diversities in the degree of resistance among GLH resistant varieties. Variation in virus transmission efficiency (biotype) among GLH populations collected from various tungro endemic areas closely related to the history of adoption of rice varieties.

scholarly journals Transmission of Grapevine leafroll-associated virus 3 by the Vine Mealybug (Planococcus ficus)

2008 ◽  
Vol 98 (10) ◽  
pp. 1093-1098 ◽  
Author(s):  
C.-W. Tsai ◽  
J. Chau ◽  
L. Fernandez ◽  
D. Bosco ◽  
K. M. Daane ◽  
...  
Keyword(s):  
Management Practices ◽  
Transmission Rate ◽  
Disease Incidence ◽  
Virus Transmission ◽  
Transmission Efficiency ◽  
Planococcus Ficus ◽  
Access Period ◽  
The World ◽  
Leafroll Disease ◽  
Vine Mealybug

Grapevine leafroll disease is caused by grapevine leafroll-associated viruses (GLRaVs). Within this virus complex, GLRaV-3 is the predominant species in the world. Several GLRaVs have been shown to be transmitted from vine to vine by mealybugs although a detailed characterization of transmission biology is lacking. The introduction of the vine mealybug (Planococcus ficus) in California and other regions of the world may result in increasing disease incidence of established GLRaVs. We studied the characteristics of GLRaV-3 transmission by the vine mealybug. Our results indicate that the vine mealybug transmits GLRaV-3 in a semipersistent manner. First instars were more efficient vectors than adult mealybugs. GLRaV-3 transmission lacked a latent period in the vector. Virus transmission occurred with a 1-h acquisition access period (AAP) and peaked with a 24-h AAP. Mealybugs inoculated GLRaV-3 with a 1-h inoculation access period (IAP), and transmission efficiency increased with longer plant access period up to 24 h, after which transmission rate remained constant. After an AAP of 24 h, mealybugs lost GLRaV-3 and infectivity 4 days after virus acquisition. In addition, GLRaV-3 was not transovarially transmitted from infected females to their progeny as detected by reverse transcription polymerase chain reaction. In summary, we systematically analyzed transmission parameters of GLRaV-3 by the vine mealybug and showed that transmission of this virus occurs in a semipersistent manner. This research fills in important gaps in knowledge of leafroll virus transmission, which is critical for development of leafroll disease management practices.

scholarly journals VARIATION IN RICE TUNGRO VIRUS TRANSMISSION ABILITY BY GREEN LEAFHOPPER, Nephotettix virescens DISTANT (HOMOPTERA: CICADELLIDAE) ON RICE RESISTANT VARIETIES

2013 ◽  
Vol 15 (2) ◽  
pp. 65
Author(s):  
I Nyoman Widiarta ◽  
Adolf Bastian ◽  
Syahrir Pakki
Keyword(s):  
Transmission Rate ◽  
Virus Transmission ◽  
Transmission Efficiency ◽  
Resistant Variety ◽  
Rice Varieties ◽  
Nephotettix Virescens ◽  
Green Leafhopper ◽  
Resistant Varieties ◽  
History Of ◽  
Efficient Vector

Green leafhopper (GLH), Nephotettix virescens, is the most efficient vector of rice tungro virus disease. The disease is endemic in some provinces of Indonesia and commonly con-trolled using resistant varieties. Resistance of rice varieties to tungro could be classified into resistance to a virus and a vector. The history of GLH resistant varieties adoption affected the GLH adaptation in an area. The study was conducted in the period of 2009-2011 to evaluate the resistance status of five GLH resistant rice variety groups (T0-T4) using survival and transmission test. The GLH populations were collected from 15 tungro endemic provinces in Indonesia. The GLH was then reared in the greenhouse before used for the test. The degree of resistance to tungro viruses was calculated by adding the value of survival (weight x score of survival rate) and virus transmission rate (weight x score of transmission rate). The weights for survival and transmission rate were set to 40 and 60, respectively. The results showed that the rank of resistant variety groups in decreasing order of resistance were T4, T1, T2 and T3. Five variations in GLH transmission efficiency were identified, i.e. 170, 070, 050, 030 and 010. GLH populations from Bali and West Nusa Tenggara were the most efficient vector for rice tungro virus. We concluded that there were diversities in the degree of resistance among GLH resistant varieties. Variation in virus transmission efficiency (biotype) among GLH populations collected from various tungro endemic areas closely related to the history of adoption of rice varieties.

scholarly journals Dynamics of the COVID-19 epidemic in Ireland under mitigation

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Bernard Cazelles ◽  
Benjamin Nguyen-Van-Yen ◽  
Clara Champagne ◽  
Catherine Comiskey
Keyword(s):  
Transmission Rate ◽  
Vaccination Campaign ◽  
Virus Transmission ◽  
Reporting Rate ◽  
Mitigation Measures ◽  
Third Wave ◽  
The European Union ◽  
Hospital Data ◽  
Prevalence Survey ◽  
Epidemic Curve

Abstract Background In Ireland and across the European Union the COVID-19 epidemic waves, driven mainly by the emergence of new variants of the SARS-CoV-2 have continued their course, despite various interventions from governments. Public health interventions continue in their attempts to control the spread as they wait for the planned significant effect of vaccination. Methods To tackle this challenge and the observed non-stationary aspect of the epidemic we used a modified SEIR stochastic model with time-varying parameters, following Brownian process. This enabled us to reconstruct the temporal evolution of the transmission rate of COVID-19 with the non-specific hypothesis that it follows a basic stochastic process constrained by the available data. This model is coupled with Bayesian inference (particle Markov Chain Monte Carlo method) for parameter estimation and utilized mainly well-documented Irish hospital data. Results In Ireland, mitigation measures provided a 78–86% reduction in transmission during the first wave between March and May 2020. For the second wave in October 2020, our reduction estimation was around 20% while it was 70% for the third wave in January 2021. This third wave was partly due to the UK variant appearing in Ireland. In June 2020 we estimated that sero-prevalence was 2.0% (95% CI: 1.2–3.5%) in complete accordance with a sero-prevalence survey. By the end of April 2021, the sero-prevalence was greater than 17% due in part to the vaccination campaign. Finally we demonstrate that the available observed confirmed cases are not reliable for analysis owing to the fact that their reporting rate has as expected greatly evolved. Conclusion We provide the first estimations of the dynamics of the COVID-19 epidemic in Ireland and its key parameters. We also quantify the effects of mitigation measures on the virus transmission during and after mitigation for the three waves. Our results demonstrate that Ireland has significantly reduced transmission by employing mitigation measures, physical distancing and lockdown. This has to date avoided the saturation of healthcare infrastructures, flattened the epidemic curve and likely reduced mortality. However, as we await for a full roll out of a vaccination programme and as new variants potentially more transmissible and/or more infectious could continue to emerge and mitigation measures change silent transmission, challenges remain.

scholarly journals A Graft-Based Chemotherapy Method for Screening Effective Molecules and Rescuing Huanglongbing-Affected Citrus Plants

2012 ◽  
Vol 102 (6) ◽  
pp. 567-574 ◽  
Author(s):  
Muqing Zhang ◽  
Charles A. Powell ◽  
Ying Guo ◽  
Melissa S. Doud ◽  
Yongping Duan
Keyword(s):  
Survival Rate ◽  
Transmission Rate ◽  
High Titer ◽  
Critical Factor ◽  
Transmission Efficiency ◽  
Pathogen Transmission ◽  
Citrus Industry ◽  
Chemical Treatments ◽  
Bacterial Titer ◽  
Transmission Studies

Huanglongbing (HLB) is the most devastating disease of citrus. The global citrus industry is in urgent need of effective chemical treatments for HLB control because of its rapid spreading worldwide. Due to the fastidious nature of the pathogens, and the poor permissibility of citrus leaf surfaces, effective screening of chemicals for the HLB control can be challenging. In this study, we developed a graft-based chemotherapy method to rapidly screen potential HLB-controlling chemical compounds. In addition, we improved transmission efficiency by using the best HLB-affected scion–rootstock combination, and demonstrated the HLB bacterial titer was the critical factor in transmission. The HLB-affected lemon scions had a high titer of HLB bacterium, survival rate (83.3%), and pathogen transmission rate (59.9%). Trifoliate, a widely used commercial rootstock, had the highest survival rate (>70.0%) compared with grapefruit (52.6%) and sour orange (50.4%). Using this method, we confirmed a mixture of penicillin and streptomycin was the most effective compounds in eliminating the HLB bacterium from the HLB-affected scions, and in successfully rescuing severely HLB-affected citrus germplasms. These findings are useful not only for chemical treatments but also for graft-based transmission studies in HLB and other Liberibacter diseases.

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