Prevalence of Flavescence Dorée Phytoplasma-Infected Scaphoideus titanus in Different Vineyard Agroecosystems of Northwestern Italy

Quantitative estimates of vector populations and their infectivity in the wild and in cultivated compartments of agroecosystems have been carried out to elucidate the role of the wild compartment in the epidemiology of Flavescence dorée (FD). Seven sites were selected for the investigations in the Piedmont Region of Italy. They were characterized by a high variety of agricultural and ecological landscape features, and included a vineyard surrounded by wild vegetation. In order to describe abundance and prevalence of FD-infected vectors in the cultivated and wild compartments of the vineyard agroecosystem, adults of Scaphoideus titanus were collected by yellow sticky traps inside and outside the vineyard over the period July 10th–September 9th, 2015. They were counted and singly analyzed for the presence of FD phytoplasmas by PCR. Multifactorial correlations among vector population level, prevalence of infected insects inside and outside the vineyards, disease prevalence in cultivated and wild Vitis plants, and location of wild Vitis plants with respect to the vineyard were analyzed. Abundance of S. titanus adults significantly decreased from the end of July onwards, particularly inside the vineyard (average range 22.7 ± 2.5 insects/trap). Percentage of FD-positive S. titanus was significantly higher outside the vineyard (up to 48% on average) compared to inside the vineyard (up to 34% on average), and increased during the season in both compartments.

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Silencing of ATP Synthase β Impairs Egg Development in the Leafhopper Scaphoideus titanus, Vector of the Phytoplasma Associated with Grapevine Flavescence Dorée

International Journal of Molecular Sciences ◽

10.3390/ijms23020765 ◽

2022 ◽

Vol 23 (2) ◽

pp. 765

Author(s):

Matteo Ripamonti ◽

Luca Cerone ◽

Simona Abbà ◽

Marika Rossi ◽

Sara Ottati ◽

...

Keyword(s):

Atp Synthase ◽

Cathepsin L ◽

Field Application ◽

Female Sterility ◽

Model Species ◽

Egg Development ◽

Flavescence Dorée ◽

Vector Population ◽

Regulatory Constraints ◽

Scaphoideus Titanus

Scaphoideus titanus (Hemiptera: Cicadellidae) is the natural vector of Flavescence dorée phytoplasma, a quarantine pest of grapevine with severe impact on European viticulture. RNA interference (RNAi) machinery components are present in S. titanus transcriptome and injection of ATP synthase β dsRNAs into adults caused gene silencing, starting three days post injection (dpi) up to 20 dpi, leading to decrease cognate protein. Silencing of this gene in the closely related leafhopper Euscelidiusvariegatus previously showed female sterility and lack of mature eggs in ovaries. Here, alteration of developing egg morphology in S. titanus ovaries as well as overexpression of hexamerin transcript (amino acid storage protein) and cathepsin L protein (lysosome proteinase) were observed in dsATP-injected females. To evaluate RNAi-specificity, E.variegatus was used as dsRNA-receiving model-species. Different doses of two sets of dsRNA-constructs targeting distinct portions of ATP synthase β gene of both species induced silencing, lack of egg development, and female sterility in E. variegatus, indicating that off-target effects must be evaluated case by case. The effectiveness of RNAi in S. titanus provides a powerful tool for functional genomics of this non-model species and paves the way toward RNAi-based strategies to limit vector population, despite several technical and regulatory constraints that still need to be overcome to allow open field application.

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Genetic Diversity of Flavescence Dorée Phytoplasmas at the Vineyard Scale

Applied and Environmental Microbiology ◽

10.1128/aem.03123-18 ◽

2019 ◽

Vol 85 (10) ◽

Cited By ~ 11

Author(s):

Marika Rossi ◽

Mattia Pegoraro ◽

Matteo Ripamonti ◽

Simona Abbà ◽

Dylan Beal ◽

...

Keyword(s):

Genetic Markers ◽

Genetic Characterization ◽

Landscape Management ◽

Content Type ◽

Flavescence Dorée ◽

Scaphoideus Titanus ◽

Geographical Scale ◽

Genetic Profiles

ABSTRACT To study the role of wild areas around the vineyards in the epidemiology of flavescence dorée (FD) and track the origin of new foci, two phytoplasma genetic markers, dnaK and malG, were developed for FD phytoplasma (FDp) characterization. The two genes and the vmpA locus were used to genetically characterize FDp populations at seven agroecosystems of a wine-growing Italian region. Vitis vinifera, “gone-wild” V. vinifera and rootstocks, Clematis spp., and Scaphoideus titanus adults were sampled within and outside the vineyards. A range of genotypes infecting the different hosts of the FDp epidemiological cycle was found. Type FD-C isolates were fairly homogeneous compared to type FD-D ones. Most of the FD-D variability was correlated with the malG sequence, and a duplication of this locus was demonstrated for this strain. Coinfection with FD-C and FD-D strains was rare, suggesting possible competition between the two. Similar levels of FDp genetic variation recorded for grapevines or leafhoppers of cultivated and wild areas and co-occurrence of many FDp genotypes inside and outside the vineyards supported the idea of the importance of wild or abandoned Vitis plants and associated S. titanus insects in the epidemiology of the disease. Genetic profiles of FDp found in Clematis were never found in the other hosts, indicating that this species does not take part in the disease cycle in the area. Due to the robustness of analyses using dnaK for discriminating between FD-C and FD-D strains and the high variability of malG sequences, these are efficient markers to study FDp populations and epidemiology at a small geographical scale. IMPORTANCE Flavescence dorée, a threatening disease of grapevine caused by FD phytoplasma (FDp), is distributed within the most important wine-producing areas of Europe and has severe effects on both vineyard productivity and landscape management. FDp is a quarantine pest in Europe, and despite the efforts to contain the pathogen, the disease is still spreading. In this work, new genetic markers for the fine genetic characterization of FDp at local scale are presented. Our findings improve the knowledge of FDp epidemiological cycle and offer the possibility of tracking the route of the FDp infection. In particular, due to its high genetic variability, one of the newly developed markers could be sufficient to track the origin of new infection foci, either from the wild areas or from nurseries.

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New Viral Sequences Identified in the Flavescence Dorée Phytoplasma Vector Scaphoideus titanus

Viruses ◽

10.3390/v12030287 ◽

2020 ◽

Vol 12 (3) ◽

pp. 287

Author(s):

Sara Ottati ◽

Marco Chiapello ◽

Luciana Galetto ◽

Domenico Bosco ◽

Cristina Marzachì ◽

...

Keyword(s):

Large Scale ◽

Control Measures ◽

Insect Vector ◽

Wine Production ◽

Flavescence Dorée ◽

Reverse Transcription Pcr ◽

Scaphoideus Titanus ◽

The Usa ◽

In The Wild ◽

Increasing Demand

(1) Background: The leafhopper Scaphoideus titanus is the primary vector of Flavescence dorée phytoplasma (FDp) in European vineyards. Flavescence dorée is one of the most severely damaging diseases of Vitis vinifera and, consequently, a major threat to grape and wine production in several European countries. Control measures are compulsory, but they mainly involve large-scale insecticide treatments, with detrimental impacts on the environment. One possible solution is to exploit the largely unexplored genetic diversity of viruses infecting S. titanus as highly specific and environmentally benign tools for biological control. (2) Methods: A metatranscriptomic approach was adopted to identify viruses that may infect individuals caught in the wild in both its native (United States) and invasive (Europe) areas. Reverse transcription PCR was used to confirm their presence in RNA pools and explore their prevalence. (3) Results: We described nine new RNA viruses, including members of “Picorna-Calici”, “Permutotetra”, “Bunya-Arena”, “Reo”, “Partiti-Picobirna”, “Luteo-Sobemo” and “Toti-Chryso” clades. A marked difference in the diversity and abundance of the viral species was observed between the USA population and the European ones. (4) Conclusions: This work represents the first survey to assess the viral community of a phytoplasma insect vector. The possibility to exploit these naturally occurring viruses as specific and targeted biocontrol agents of S. titanus could be the answer to increasing demand for a more sustainable viticulture.

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Patterns of Evolution

Morphogenesis and Evolution ◽

10.1093/oso/9780195049121.003.0010 ◽

1988 ◽

Author(s):

Keith Stewart Thomson

Keyword(s):

Evolutionary Process ◽

Population Level ◽

Comparative Morphology ◽

Species Level ◽

Developmental Level ◽

Evolutionary Mechanisms ◽

Evolutionary Patterns ◽

In The Wild ◽

Evolutionary Science

We now need to look more closely at the evolutionary patterns that we wish to explain. Again, we can use the study of patterns to discover and define important problems to be solved. The methods available for the study of patterns depend on the focal level of the mechanism with which one is concerned. If our interest is in individual variation, naturally we need extensive sampling and laboratory experimentation, looking at individuals within populations. In order to study the biology of populations we must work at the population level, and at such phenomena as gene and character frequencies in the field and laboratory. It is at this level that workers have most readily been able to measure selection coefficients and other quantitative elements of evolutionary science. If our interest is in the processes of speciation we must look as closely as possible at examples of the process in action—at sibling species, at a whole range of hybridization patterns in the wild and laboratory, at the distribution of closely related species in space and time. (It will be noted that between population-level work and species-level work there is an unfortunate gap; one can look at prespeciation and postspeciation situations but it is rare indeed to be confident that one is looking at speciation in flagrante delicto.) We can also look beyond the species level at phenomena of species distribution within higher taxa. Here we progress to using the methods of systematic biology and comparative morphology and paleontology. Each of these different approaches gives a different view of the evolutionary process and, therefore, in terms of the questions discussed in this book, gives us a different view of the role of mechanisms acting at the developmental level within evolutionary mechanisms. Obviously the most immediate element of causality in the origin of adaptive structures resulting from developmental properties is in the matter of individual phenotypic variation, but some of the most interesting questions concern the consequences of developmental properties for higher focal levels—their upwardly causing properties. To examine these we need to look at the species level and beyond (what has often been termed croevolution).

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The role of habitat configuration in shaping animal population processes: a framework to generate quantitative predictions

Oecologia ◽

10.1007/s00442-021-04967-y ◽

2021 ◽

Author(s):

Peng He ◽

Pierre-Olivier Montiglio ◽

Marius Somveille ◽

Mauricio Cantor ◽

Damien R. Farine

Keyword(s):

Population Level ◽

R Package ◽

Habitat Configuration ◽

Modelling Framework ◽

Alternative Habitat ◽

Animal Populations ◽

Research Questions ◽

Habitat Networks ◽

Animal Habitat

AbstractBy shaping where individuals move, habitat configuration can fundamentally structure animal populations. Yet, we currently lack a framework for generating quantitative predictions about the role of habitat configuration in modulating population outcomes. To address this gap, we propose a modelling framework inspired by studies using networks to characterize habitat connectivity. We first define animal habitat networks, explain how they can integrate information about the different configurational features of animal habitats, and highlight the need for a bottom–up generative model that can depict realistic variations in habitat potential connectivity. Second, we describe a model for simulating animal habitat networks (available in the R package AnimalHabitatNetwork), and demonstrate its ability to generate alternative habitat configurations based on empirical data, which forms the basis for exploring the consequences of alternative habitat structures. Finally, we lay out three key research questions and demonstrate how our framework can address them. By simulating the spread of a pathogen within a population, we show how transmission properties can be impacted by both local potential connectivity and landscape-level characteristics of habitats. Our study highlights the importance of considering the underlying habitat configuration in studies linking social structure with population-level outcomes.

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An increasing role of pyrethroid-resistant Anopheles funestus in malaria transmission in the Lake Zone, Tanzania

Scientific Reports ◽

10.1038/s41598-021-92741-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Nancy S. Matowo ◽

Jackline Martin ◽

Manisha A. Kulkarni ◽

Jacklin F. Mosha ◽

Eliud Lukole ◽

...

Keyword(s):

Malaria Transmission ◽

Anopheles Funestus ◽

Sub Saharan Africa ◽

North West ◽

Vector Population ◽

Lake Zone ◽

Sub Saharan ◽

Long Lasting Insecticidal Nets ◽

Study District

AbstractAnopheles funestus is playing an increasing role in malaria transmission in parts of sub-Saharan Africa, where An. gambiae s.s. has been effectively controlled by long-lasting insecticidal nets. We investigated vector population bionomics, insecticide resistance and malaria transmission dynamics in 86 study clusters in North-West Tanzania. An. funestus s.l. represented 94.5% (4740/5016) of all vectors and was responsible for the majority of malaria transmission (96.5%), with a sporozoite rate of 3.4% and average monthly entomological inoculation rate (EIR) of 4.57 per house. Micro-geographical heterogeneity in species composition, abundance and transmission was observed across the study district in relation to key ecological differences between northern and southern clusters, with significantly higher densities, proportions and EIR of An. funestus s.l. collected from the South. An. gambiae s.l. (5.5%) density, principally An. arabiensis (81.1%) and An. gambiae s.s. (18.9%), was much lower and closely correlated with seasonal rainfall. Both An. funestus s.l. and An. gambiae s.l. were similarly resistant to alpha-cypermethrin and permethrin. Overexpression of CYP9K1, CYP6P3, CYP6P4 and CYP6M2 and high L1014S-kdr mutation frequency were detected in An. gambiae s.s. populations. Study findings highlight the urgent need for novel vector control tools to tackle persistent malaria transmission in the Lake Region of Tanzania.

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Transcriptome Changes in Pseudomonas putida KT2440 during Medium-Chain-Length Polyhydroxyalkanoate Synthesis Induced by Nitrogen Limitation

International Journal of Molecular Sciences ◽

10.3390/ijms22010152 ◽

2020 ◽

Vol 22 (1) ◽

pp. 152

Author(s):

Dorota Dabrowska ◽

Justyna Mozejko-Ciesielska ◽

Tomasz Pokój ◽

Slawomir Ciesielski

Keyword(s):

Chain Length ◽

Nitrogen Limitation ◽

Stringent Response ◽

Wild Type ◽

Pseudomonas Putida Kt2440 ◽

Medium Chain ◽

Environmental Stimuli ◽

Medium Chain Length ◽

In The Wild

Pseudomonas putida’s versatility and metabolic flexibility make it an ideal biotechnological platform for producing valuable chemicals, such as medium-chain-length polyhydroxyalkanoates (mcl-PHAs), which are considered the next generation bioplastics. This bacterium responds to environmental stimuli by rearranging its metabolism to improve its fitness and increase its chances of survival in harsh environments. Mcl-PHAs play an important role in central metabolism, serving as a reservoir of carbon and energy. Due to the complexity of mcl-PHAs’ metabolism, the manner in which P. putida changes its transcriptome to favor mcl-PHA synthesis in response to environmental stimuli remains unclear. Therefore, our objective was to investigate how the P. putida KT2440 wild type and mutants adjust their transcriptomes to synthesize mcl-PHAs in response to nitrogen limitation when supplied with sodium gluconate as an external carbon source. We found that, under nitrogen limitation, mcl-PHA accumulation is significantly lower in the mutant deficient in the stringent response than in the wild type or the rpoN mutant. Transcriptome analysis revealed that, under N-limiting conditions, 24 genes were downregulated and 21 were upregulated that were common to all three strains. Additionally, potential regulators of these genes were identified: the global anaerobic regulator (Anr, consisting of FnrA, Fnrb, and FnrC), NorR, NasT, the sigma54-dependent transcriptional regulator, and the dual component NtrB/NtrC regulator all appear to play important roles in transcriptome rearrangement under N-limiting conditions. The role of these regulators in mcl-PHA synthesis is discussed.

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Mutability of demographic noise in microbial range expansions

The ISME Journal ◽

10.1038/s41396-021-00951-9 ◽

2021 ◽

Author(s):

QinQin Yu ◽

Matti Gralka ◽

Marie-Cécilia Duvernoy ◽

Megan Sousa ◽

Arbel Harpak ◽

...

Keyword(s):

Gene Deletion ◽

Genetic Manipulation ◽

Single Gene ◽

Population Level ◽

Growth Conditions ◽

Establishment Probability ◽

In The Wild ◽

Order Of Magnitude ◽

Demographic Noise ◽

Single Gene Deletion

AbstractDemographic noise, the change in the composition of a population due to random birth and death events, is an important driving force in evolution because it reduces the efficacy of natural selection. Demographic noise is typically thought to be set by the population size and the environment, but recent experiments with microbial range expansions have revealed substantial strain-level differences in demographic noise under the same growth conditions. Many genetic and phenotypic differences exist between strains; to what extent do single mutations change the strength of demographic noise? To investigate this question, we developed a high-throughput method for measuring demographic noise in colonies without the need for genetic manipulation. By applying this method to 191 randomly-selected single gene deletion strains from the E. coli Keio collection, we find that a typical single gene deletion mutation decreases demographic noise by 8% (maximal decrease: 81%). We find that the strength of demographic noise is an emergent trait at the population level that can be predicted by colony-level traits but not cell-level traits. The observed differences in demographic noise from single gene deletions can increase the establishment probability of beneficial mutations by almost an order of magnitude (compared to in the wild type). Our results show that single mutations can substantially alter adaptation through their effects on demographic noise and suggest that demographic noise can be an evolvable trait of a population.

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Premating barriers in young sympatric snail species

Scientific Reports ◽

10.1038/s41598-021-84407-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Arina L. Maltseva ◽

Marina A. Varfolomeeva ◽

Arseniy A. Lobov ◽

Polina O. Tikanova ◽

Egor A. Repkin ◽

...

Keyword(s):

Gene Flow ◽

Snail Species ◽

Sympatric Populations ◽

Gastropod Species ◽

Shell Size ◽

Closely Related Species ◽

Partial Canonical Correspondence Analysis ◽

In The Wild ◽

Isolation Index

AbstractSympatric coexistence of recently diverged species raises the question of barriers restricting the gene flow between them. Reproductive isolation may be implemented at several levels, and the weakening of some, e.g. premating, barriers may require the strengthening of the others, e.g. postcopulatory ones. We analysed mating patterns and shell size of mates in recently diverged closely related species of the subgenus Littorina Neritrema (Littorinidae, Caenogastropoda) in order to assess the role of premating reproductive barriers between them. We compared mating frequencies observed in the wild with those expected based on relative densities using partial canonical correspondence analysis. We introduced the fidelity index (FI) to estimate the relative accuracy of mating with conspecific females and precopulatory isolation index (IPC) to characterize the strength of premating barriers. The species under study, with the exception of L. arcana, clearly demonstrated preferential mating with conspecifics. According to FI and IPC, L. fabalis and L. compressa appeared reliably isolated from their closest relatives within Neritrema. Individuals of these two species tend to be smaller than those of the others, highlighting the importance of shell size changes in gastropod species divergence. L. arcana males were often found in pairs with L. saxatilis females, and no interspecific size differences were revealed in this sibling species pair. We discuss the lack of discriminative mate choice in the sympatric populations of L. arcana and L. saxatilis, and possible additional mechanisms restricting gene flow between them.

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