scholarly journals Vector manipulation by a semi-persistent plant virus through disease symptom expression

2020 ◽  
Author(s):  
Diego F. Vasquez ◽  
Felipe Borrero-Echeverry ◽  
Diego F. Rincon
Keyword(s):  
Development Time ◽  
Host Preference ◽  
Horizontal Transmission ◽  
Disease Symptom ◽  
List Type ◽  
Symptom Expression ◽  
Insect Behaviour ◽  
Greenhouse Whitefly ◽  
Transmission Rates ◽  
Potato Plants

AbstractThe greenhouse whitefly (GWF), Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) is rarely associated with potato plants yet is the only known vector of the Potato yellow vein virus (PYVV). A host shift related with vector’s cognition often requires neural alterations by the virus. However, PYVV, being semi-persistent, is not supposed to directly affect vector physiology. As such, we propose that changes in potato plants caused by PYVV infection should manipulate insect behaviour to increase transmission. Here, we studied the effect of PYVV infection and symptom expression on GWF biological parameters, and attraction towards infected and uninfected potato plants. We compared survival and development rates of GWF nymphs fed with PYVV-infected plants (symptomatic and asymptomatic) and healthy plants under controlled conditions. We also carried out free-choice tests to determine host preference of GWF adults as a function of PYVV infection and disease symptom expression. We found that PYVV infection (both symptomatic and asymptomatic) reduce GWF survival while increasing development time (in symptomatic plants). Combined, a prolonged development time and reduced survival should favour viral uptake and trigger migration of vectors from symptomatic plants short after acquiring the virus. We also found that symptom expression (yellowing) causes significantly greater GWF attraction and establishment compared to healthy or asymptomatic plants. Interestingly, we found that GWF adults that have previously fed on infected plants switch their host preference choosing and establishing on healthy potato plants, which clearly increases horizontal transmission rates. The mechanism through which this behavioural manipulation takes place is not yet well understood. Our results show that symptoms associated with PYVV infection may account for a set of behavioural modifications that make an improbable vector, such as the GWF, into an efficient agent that increases horizontal transmission rates of PYVV.HighlightsPYVD reduces the survival of GWF and increases development time when symptoms occurPYVD symptom makes potato, a non-host plant, attractive to GWFAfter feeding on infected plants, GWF preference changes to prefer uninfected plantsPYVV modulates GWF behaviour to enhance horizontal transmission between plants

scholarly journals Strain-Specific Hypersensitive and Extreme Resistance Phenotypes Elicited by Potato virus Y Among 39 Potato Cultivars Released in Three World Regions Over a 117-Year Period

Plant Disease ◽  
2018 ◽  
Vol 102 (1) ◽  
pp. 185-196 ◽  
Author(s):  
Roger A. C. Jones ◽  
Stuart J. Vincent
Keyword(s):  
Potato Virus ◽  
Potato Virus Y ◽  
Secondary Infection ◽  
Potato Cultivars ◽  
Symptom Expression ◽  
Extreme Resistance ◽  
Potato Plants ◽  
Pvy Resistance ◽  
World Regions ◽  
Healthy Seed

Strain-specific hypersensitive (HR) and extreme resistance (ER) phenotypes elicited in potato plants by three Potato virus Y (PVY) isolates in strain groups PVYO (BL and DEL3) and PVYD (KIP1) were studied. PVYO and PVYD isolates elicit HR genes Ny or putative Nd, respectively, and all three isolates elicit ER gene Ry. They were inoculated to 39 Australasian, European, or North American potato cultivars released over a 117-year period and harvested tubers were replanted. Both primary and secondary symptoms were recorded. Two European cultivars always developed ER following sap and graft inoculation and, thus, carried comprehensive PVY resistance gene Ry. One Australasian and two European cultivars always developed susceptible phenotypes and, thus, lacked genes Ry, Ny, and putative Nd. Sap inoculation with isolate KIP1 elicited localized HR (LHR) in 31 cultivars and both LHR and systemic HR (SHR) in three others; thus, all carried putative Nd. Isolates BL and DEL3 both elicited susceptible phenotypes in 11 of these 34 cultivars but LHR alone, SHR alone, or both LHR and SHR in the other 23 which, therefore, all carry Ny. With these two isolates, SHR expression ranged from very severe to very weak, with the greatest numbers of isolate–cultivar combinations occurring in the severe category with BL (n = 11) and moderate category (n = 12) with DEL3. Within the same isolate–cultivar combination, overall, SHR symptom expression was weaker with secondary than primary infection. With both primary and secondary infection, SHR expression was most severe with KIP1 and weakest with DEL3. Genes Ny and putative Nd were present in cultivars released between 1939 and 2010 or 1893 and 2010, respectively, occurring in cultivars from all three world regions. These findings have important implications concerning breeding new PVY-resistant potato cultivars, especially for countries lacking healthy seed potato stocks, or where subsistence farmers cannot afford them. An alternative to including gene Ry is incorporating as many strain-specific PVY resistance genes as possible.

scholarly journals A critical review of the use and performance of different function types for modeling temperature-dependent development of arthropod larvae

2016 ◽  
Author(s):  
Brady K. Quinn
Keyword(s):  
Development Time ◽  
Single Type ◽  
Published Data ◽  
List Type ◽  
Temperature Dependent ◽  
Function Type ◽  
Dependent Development ◽  
Development Times ◽  
Complex Functions ◽  
Incorrect Model

ABSTRACTTemperature-dependent development influences production rates of arthropods, including crustaceans important to fisheries and agricultural pests. Numerous candidate equation types (development functions) exist to describe the effect of temperature on development time, yet most studies use only a single type of equation and there is no consensus as to which, if any model predicts development rates better than the others, nor what the consequences of selecting a potentially incorrect model equation are on predicted development times. In this study, a literature search was performed of studies fitting development functions to development of arthropod larvae (99 species). The published data of most (79) of these species were then fit with 33 commonly-used development functions. Overall performance of each function type and consequences of using a function other than the best one to model data were assessed. Performance was also related to taxonomy and the range of temperatures examined. The majority (91.1 %) of studies were found to not use the best function out of those tested. Using the incorrect model lead to significantly less accurate (e.g., mean difference ± SE 85.9 ± 27.4 %, range: −1.7 to 1725.5 %) predictions of development times than the best function. Overall, more complex functions performed poorly relative to simpler ones. However, performance of some complex functions improved when wide temperature ranges were tested, which tended to be confined to studies of insects or arachnids compared with those of crustaceans. Results indicate the biological significance of choosing the best-fitting model to describe temperature-dependent development time data.HighlightsTemperature-dependent development functions of arthropod larvae were reviewed79 published datasets were re-tested and fit with 33 different function types91.1 % of published studies did not fit their data with the best function of those testedPerformance differed among functions and was related to taxon and temperature range testedFunction type impacted predicted development times, so using the best function matters

Effect of Mi-1.2 gene in Natal Host Plants on Behavior and Biology of the Tomato Psyllid Bactericerca cockerelli (Sulc) (Hemiptera: Psyllidae)

2007 ◽  
Vol 42 (2) ◽  
pp. 155-162 ◽  
Author(s):  
Clare L. Casteel ◽  
Linda L. Walling ◽  
Timothy D. Paine
Keyword(s):  
Host Selection ◽  
Host Plants ◽  
Development Time ◽  
Host Preference ◽  
Solanum Lycopersicon ◽  
As Species ◽  
Useful Components ◽  
Survival And Development ◽  
Subsequent Selection ◽  
Selection Of

The Mi-1.2 gene has been isolated from wild varieties of tomato, Solanum peruvianum (Mill), and incorporated into near isogenic commercial varieties of tomato, Solanum lycopersicon. Plants containing the gene confer resistance to tomato psyllid, Bactericerca cockerelli (Sulc), as well as species of aphids, whiteflies, and nematodes. Considering bias in host preference and oviposition responses based on early adult experience is well documented in the literature; the objective of this study was to determine if the presence or absence of the Mi-1.2 in the rearing host influenced subsequent host selection, oviposition, and development time. The results presented here show that the host that psyllids developed on did not affect subsequent selection of host for oviposition, but incidence of oviposition was higher on plants that did not contain the Mi-1.2 gene [Moneymaker (mi-1.2)] compared to plants with the Mi-1.2 gene [Motelle (Mi-1.2)]. Psyllid nymph survival and development time did not differ between plant varieties. Consequently, plants containing the gene may be useful components to IPM programs to control the tomato psyllid.

scholarly journals Vertical transmission of zika virus in Aedes albopictus

2020 ◽  
Vol 14 (10) ◽  
pp. e0008776
Author(s):  
Zetian Lai ◽  
Tengfei Zhou ◽  
Jiayong Zhou ◽  
Shuang Liu ◽  
Ye Xu ◽  
...  
Keyword(s):  
Vertical Transmission ◽  
Aedes Albopictus ◽  
Reverse Transcription ◽  
Zika Virus ◽  
Transmission Rate ◽  
Horizontal Transmission ◽  
Infection Rates ◽  
Transmission Rates ◽  
Suckling Mice ◽  
Reverse Transcription Pcr

Background Zika virus (ZIKV) is an arthropod-borne flavivirus transmitted by Aedes mosquitoes. Aedes albopictus is an important vector of ZIKV worldwide. To date, most experiments have focused on the vertical transmission of ZIKV in Ae. aegypti, while studies on Ae. albopictus are very limited. To explore vertical transmission in Ae. albopictus, a series of laboratory studies were carried out. Methodology/Principal findings In this study, Ae. albopictus were blood-fed with ZIKV-infectious blood, and the ovaries and offspring viral infection rates were analyzed by reverse transcription PCR (RT-PCR), real-time reverse transcription PCR (RT-qPCR) and immunohistochemistry (IHC). ZIKV was detected in the ovaries and oviposited eggs in two gonotrophic cycles. The minimum filial egg infection rates in two gonotrophic cycles were 2.06% and 0.69%, and the effective population transmission rate was 1.87%. The hatching, pupation, and emergence rates of infected offspring were not significantly different from those of uninfected offspring, indicating that ZIKV did not prevent the offspring from completing the growth and development process. ZIKV was detected in three of thirteen C57BL/6 suckling mice bitten by ZIKV-positive F1 females, and the viremia persisted for at least seven days. Conclusions/Significance ZIKV can be vertically transmitted in Ae. albopictus via transovarial transmission. The vertical transmission rates in F1 eggs and adults were 2.06% and 1.87%, respectively. Even though the vertical transmission rates were low, the female mosquitoes infected via the congenital route horizontally transmitted ZIKV to suckling mice through bloodsucking. This is the first experimental evidence of offspring with vertically transmitted ZIKV initiating new horizontal transmission. The present study deepens the understanding of the vertical transmission of flaviviruses in Aedes mosquitoes and sheds light on the prevention and control of mosquito-borne diseases.

scholarly journals Recombination and Migration of Cryphonectria hypovirus 1 as Inferred From Gene Genealogies and the Coalescent

Genetics ◽  
2004 ◽  
Vol 166 (4) ◽  
pp. 1611-1629
Author(s):  
Ignazio Carbone ◽  
Yir-Chung Liu ◽  
Bradley I Hillman ◽  
Michael G Milgroom
Keyword(s):  
Horizontal Transmission ◽  
Natural Populations ◽  
Recognition System ◽  
Cryphonectria Parasitica ◽  
Pathogen Transmission ◽  
Vegetative Compatibility ◽  
Common Mutation ◽  
Transmission Rates ◽  
And Migration ◽  
Cryphonectria Hypovirus

Abstract Genealogy-based methods were used to estimate migration of the fungal virus Cryphonectria hypovirus 1 between vegetative compatibility types of the host fungus, Cryphonectria parasitica, as a means of estimating horizontal transmission within two host populations. Vegetative incompatibility is a self/non-self recognition system that inhibits virus transmission under laboratory conditions but its effect on transmission in nature has not been clearly demonstrated. Recombination within and among different loci in the virus genome restricted the genealogical analyses to haplotypes with common mutation and recombinational histories. The existence of recombination necessitated that we also use genealogical approaches that can take advantage of both the mutation and recombinational histories of the sample. Virus migration between populations was significantly restricted. In contrast, estimates of migration between vegetative compatibility types were relatively high within populations despite previous evidence that transmission in the laboratory was restricted. The discordance between laboratory estimates and migration estimates from natural populations highlights the challenges in estimating pathogen transmission rates. Genealogical analyses inferred migration patterns throughout the entire coalescent history of one viral region in natural populations and not just recent patterns of migration or laboratory transmission. This application of genealogical analyses provides markedly stronger inferences on overall transmission rates than laboratory estimates do.

scholarly journals Increased copy number couples the evolution of plasmid horizontal transmission and plasmid-encoded antibiotic resistance

2021 ◽  
Vol 118 (31) ◽  
pp. e2107818118
Author(s):  
Tatiana Dimitriu ◽  
Andrew C. Matthews ◽  
Angus Buckling
Keyword(s):  
Copy Number ◽  
Horizontal Transmission ◽  
Bacterial Host ◽  
Transfer Rates ◽  
Transmission Rates ◽  
Plasmid R1 ◽  
Copy Numbers ◽  
Selection For ◽  
High Concentrations ◽  
Plasmid Carriage

Conjugative plasmids are mobile elements that spread horizontally between bacterial hosts and often confer adaptive phenotypes, including antimicrobial resistance (AMR). Theory suggests that opportunities for horizontal transmission favor plasmids with higher transfer rates, whereas selection for plasmid carriage favors less-mobile plasmids. However, little is known about the mechanisms leading to variation in transmission rates in natural plasmids or the resultant effects on their bacterial host. We investigated the evolution of AMR plasmids confronted with different immigration rates of susceptible hosts. Plasmid RP4 did not evolve in response to the manipulations, but plasmid R1 rapidly evolved up to 1,000-fold increased transfer rates in the presence of susceptible hosts. Most evolved plasmids also conferred on their hosts the ability to grow at high concentrations of antibiotics. This was because plasmids evolved greater copy numbers as a function of mutations in the copA gene controlling plasmid replication, causing both higher transfer rates and AMR. Reciprocally, plasmids with increased conjugation rates also evolved when selecting for high levels of AMR, despite the absence of susceptible hosts. Such correlated selection between plasmid transfer and AMR could increase the spread of AMR within populations and communities.

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