scholarly journals Insect Transmission of Plant Pathogens: a Systems Biology Perspective

mSystems ◽  
2018 ◽  
Vol 3 (2) ◽  
pp. e00168-17 ◽  
Author(s):  
Michelle Heck
Keyword(s):  
Systems Biology ◽  
Human Health ◽  
Plant Pathogens ◽  
Control Strategies ◽  
Global Scale ◽  
Pathogen Transmission ◽  
Effective Control ◽  
Insect Vector ◽  
Insect Vectors ◽  
Vector Systems

ABSTRACT Insect-vectored pathogens pose one of the greatest threats to plant and animal, including human, health on a global scale. Few effective control strategies have been developed to thwart the transmission of any insect-transmitted pathogen. Most have negative impacts on the environment and human health and are unsustainable. Plant pathogen transmission by insect vectors involves a combination of coevolving biological players: plant hosts, insect vectors, plant pathogens, and bacterial endosymbionts harbored by the insect. Our ability to help growers to control vector-borne disease depends on our ability to generate pathogen- and/or disease-resistant crops by traditional or synthetic approaches and to block pathogen transmission by the insect vector. Systems biology studies have led to the reexamination of existing paradigms on how pathogens interact with insect vectors, including the bacterial symbionts, and have identified vector-pathogen interactions at the molecular and cellular levels for the development of novel transmission interdiction strategies.

scholarly journals Percolation-Based Risk Index for Pathogen Invasion: Application to Soilborne Disease in Propagation Systems

2013 ◽  
Vol 103 (10) ◽  
pp. 1012-1019 ◽  
Author(s):  
S. Poggi ◽  
F. M. Neri ◽  
V. Deytieux ◽  
A. Bates ◽  
W. Otten ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Control Strategies ◽  
Risk Index ◽  
Host Density ◽  
Transmission Probability ◽  
Pathogen Transmission ◽  
Soilborne Disease ◽  
Pathogen Invasion ◽  
Fungal Plant Pathogens ◽  
Set Up

Propagation systems for seedling growth play a major role in agriculture, and in notable cases (such as organic systems), are under constant threat from soil and seedborne fungal plant pathogens such as Rhizoctonia solani or Pythium spp. Yet, to date little is known that links the risk of disease invasion to the host density, which is an agronomic characteristic that can be readily controlled. We introduce here, for the first time in an agronomic system, a percolation framework to analyze the link. We set up an experiment to study the spread of the ubiquitous fungus R. solani in replicated propagation systems with different planting densities, and fit a percolation-based epidemiological model to the data using Bayesian inference methods. The estimated probability of pathogen transmission between infected and susceptible plants is used to calculate the risk of invasion. By comparing the transmission probability and the risk values obtained for different planting densities, we are able to give evidence of a nonlinear relationship between disease invasion and the inter-plant spacing, hence to demonstrate the existence of a spatial threshold for epidemic invasion. The implications and potential use of our methods for the evaluation of disease control strategies are discussed.

scholarly journals Genomic analysis of the brassica pathogen turnip mosaic potyvirus reveals its spread along the former trade routes of the Silk Road

2021 ◽  
Vol 118 (12) ◽  
pp. e2021221118
Author(s):  
Shusuke Kawakubo ◽  
Fangluan Gao ◽  
Shifang Li ◽  
Zhongyang Tan ◽  
Ying-Kun Huang ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Control Strategies ◽  
Crop Protection ◽  
Genomic Analysis ◽  
Global Scale ◽  
Silk Road ◽  
Genome Sequences ◽  
Trade Routes ◽  
Migration Pathways ◽  
The Silk Road

Plant pathogens have agricultural impacts on a global scale and resolving the timing and route of their spread can aid crop protection and inform control strategies. However, the evolutionary and phylogeographic history of plant pathogens in Eurasia remains largely unknown because of the difficulties in sampling across such a large landmass. Here, we show that turnip mosaic potyvirus (TuMV), a significant pathogen of brassica crops, spread from west to east across Eurasia from about the 17th century CE. We used a Bayesian phylogenetic approach to analyze 579 whole genome sequences and up to 713 partial sequences of TuMV, including 122 previously unknown genome sequences from isolates that we collected over the past five decades. Our phylogeographic and molecular clock analyses showed that TuMV isolates of the Asian-Brassica/Raphanus (BR) and basal-BR groups and world-Brassica3 (B3) subgroup spread from the center of emergence to the rest of Eurasia in relation to the host plants grown in each country. The migration pathways of TuMV have retraced some of the major historical trade arteries in Eurasia, a network that formed the Silk Road, and the regional variation of the virus is partly characterized by different type patterns of recombinants. Our study presents a complex and detailed picture of the timescale and major transmission routes of an important plant pathogen.

scholarly journals Bacteriophage-Host Association in the Phytoplasma Insect Vector Euscelidius variegatus

Pathogens ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 612
Author(s):  
Marta Vallino ◽  
Marika Rossi ◽  
Sara Ottati ◽  
Gabriele Martino ◽  
Luciana Galetto ◽  
...  
Keyword(s):  
Crop Production ◽  
Axenic Culture ◽  
Pathogen Transmission ◽  
Economic Losses ◽  
Insect Vector ◽  
Insect Vectors ◽  
Electron Microscopic ◽  
Flavescence Dorée ◽  
Euscelidius Variegatus ◽  
Complex Relationships

Insect vectors transmit viruses and bacteria that can cause severe diseases in plants and economic losses due to a decrease in crop production. Insect vectors, like all other organisms, are colonized by a community of various microorganisms, which can influence their physiology, ecology, evolution, and also their competence as vectors. The important ecological meaning of bacteriophages in various ecosystems and their role in microbial communities has emerged in the past decade. However, only a few phages have been described so far in insect microbiomes. The leafhopper Euscelidius variegatus is a laboratory vector of the phytoplasma causing Flavescence dorée, a severe grapevine disease that threatens viticulture in Europe. Here, the presence of a temperate bacteriophage in E. variegatus (named Euscelidius variegatus phage 1, EVP-1) was revealed through both insect transcriptome analyses and electron microscopic observations. The bacterial host was isolated in axenic culture and identified as the bacterial endosymbiont of E. variegatus (BEV), recently assigned to the genus Candidatus Symbiopectobacterium. BEV harbors multiple prophages that become active in culture, suggesting that different environments can trigger different mechanisms, finely regulating the interactions among phages. Understanding the complex relationships within insect vector microbiomes may help in revealing possible microbe influences on pathogen transmission, and it is a crucial step toward innovative sustainable strategies for disease management in agriculture.

scholarly journals Integrating population genetic structure, microbiome, and pathogens presence data in Dermacentor variabilis

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9367 ◽  
Author(s):  
Paula Lado ◽  
Bo Luan ◽  
Michelle E.J. Allerdice ◽  
Christopher D. Paddock ◽  
Sandor E. Karpathy ◽  
...  
Keyword(s):  
Population Genetic ◽  
Control Strategies ◽  
Dermacentor Variabilis ◽  
Pathogen Transmission ◽  
Effective Control ◽  
Data Sets ◽  
Ecological Processes ◽  
Presence Data ◽  
Interdisciplinary Approaches ◽  
Lines Of Evidence

Tick-borne diseases (TBDs) continue to emerge and re-emerge in several regions of the world, highlighting the need for novel and effective control strategies. The development of effective strategies requires a better understanding of TBDs ecology, and given the complexity of these systems, interdisciplinary approaches are required. In recent years, the microbiome of vectors has received much attention, mainly because associations between native microbes and pathogens may provide a new promising path towards the disruption of pathogen transmission. However, we still do not fully understand how host genetics and environmental factors interact to shape the microbiome of organisms, or how pathogenic microorganisms affect the microbiome and vice versa. The integration of different lines of evidence may be the key to improve our understanding of TBDs ecology. In that context, we generated microbiome and pathogen presence data for Dermacentor variabilis, and integrated those data sets with population genetic data, and metadata for the same individual tick specimens. Clustering and multivariate statistical methods were used to combine, analyze, and visualize data sets. Interpretation of the results is challenging, likely due to the low levels of genetic diversity and the high abundance of a few taxa in the microbiome. Francisella was dominant in almost all ticks, regardless of geography or sex. Nevertheless, our results showed that, overall, ticks from different geographic regions differ in their microbiome composition. Additionally, DNA of Rickettsia rhipicephali, R. montanensis, R. bellii, and Anaplasma spp., was detected in D. variabilis specimens. This is the first study that successfully generated microbiome, population genetics, and pathogen presence data from the same individual ticks, and that attempted to combine the different lines of evidence. The approaches and pre-processing steps used can be applied to a variety of taxa, and help better understand ecological processes in biological systems.

scholarly journals Detection of multiple circulating Leishmania species in Lutzomyia longipalpis in the city of Governador Valadares, southeastern Brazil

2018 ◽  
Author(s):  
Mariana Santos Cardoso ◽  
Gabrielle Ariadine Bento ◽  
Laila Viana de Almeida ◽  
Joseane Camilla de Castro ◽  
João Luís Reis Cunha ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Infection Rate ◽  
Control Strategies ◽  
Minas Gerais ◽  
Domestic Dogs ◽  
Effective Control ◽  
Lutzomyia Longipalpis ◽  
Insect Vector ◽  
Sand Flies ◽  
The City

AbstractBackgroundLeishmaniasis encompasses a group of diverse clinical diseases caused by protozoan parasites of the Leishmania genus. This disease is a major public health problem in the New World affecting people exposed in endemic regions. The city of Governador Valadares (Minas Gerais/Brazil) is a re-emerging area for visceral leishmaniasis, with 191 human cases reported from 2008 to 2017 and a lethality rate of 14.7%. The transmission of the parasite occurs intensely in this region with up to 22% of domestic dogs with positive serology for the visceral form. Lu. longipalpis is one of the most abundant sand fly species in this area. Despite this scenario, so far there is no information regarding the circulating Leishmania species in the insect vector Lutzomyia longipalpis in this focus.Methodology/Principal FindingsWe collected 616 female Lutzomyia longipalpis sand flies between January and September 2015 in the Vila Parque Ibituruna neighborhood (Governador Valadares/MG), which is located on a transitional area between the sylvatic and urban environments with residences built near a preserved area. After DNA extraction of individual sand flies, the natural Leishmania infections in Lu. longipalpis were detected by end-point PCR, using primers derived from kDNA sequences, specific for L. (Leishmania) or L. (Viannia) subgenus. The sensitivity of these PCR reactions was 0.1 pg of DNA for each Leishmania subgenus and the total infection rate of 16.2% (100 positive specimens). Species-specific PCR detected the presence of multiple Leishmania species in infected Lu. longipalpis specimens in Governador Valadares, including L. amazonensis (n=3), L. infantum (n=28), L. (Viannia) spp. (n=20), coinfections with L. infantum and L. (Viannia) spp. (n=5), and L. (Leishmania) spp (n=44).ConclusionsOur results demonstrate that multiple Leishmania species circulate in Lu. longipalpis in Governador Valadares and reveal a potential increasing risk of transmission of the different circulating parasite species. This information is a key factor for planning surveillance and effective control strategies against leishmaniasis in this endemic focus.Author summaryLeishmaniasis is a neglected tropical disease transmitted to mammals by the bite of sand flies infected with parasites of the Leishmania genus. This disease affects millions of people in various regions of the world, including Brazil. The municipality of Governador Valadares (Minas Gerais/Brazil) is a re-emergent focus of intense transmission of leishmaniasis, with a high number of human cases and a high prevalence of infected domestic dogs. To develop better leishmaniasis control strategies for the region, we performed a surveillance study of Lu. longipalpis, the main vector of visceral leishmaniasis in Brazil, and identified circulating species of Leishmania in this insect vector. We estimate that the natural infection rate of Lu. longipalpis for these parasites was of 16.2% in the study area. We also detected the presence of multiple circulating Leishmania species (L. amazonensis, L. infantum and Viannia subgenus) in Lu. longipalpis in Governador Valadares city, including 5 sand flies coinfected with L. infantum and L. (Viannia). Thus, our results reinforce the need for a rigid and systematic control of the sand flies monitoring in this area, due to the potential risk of transmission of different species of the Leishmania parasites.

Made for each other: Vector-pathogen interfaces in the Huanglongbing pathosystem

2021 ◽  
Author(s):  
Nabil Killiny
Keyword(s):  
Plant Pathogens ◽  
Management Strategies ◽  
Tca Cycle ◽  
Detoxification Enzymes ◽  
Insect Vector ◽  
Insect Vectors ◽  
Plant Host ◽  
Atp Production ◽  
Molecular Features ◽  
Animal Pathogens

Citrus greening, or Huanglongbing (HLB), currently is the most destructive disease of citrus. HLB disease is putatively caused by the phloem-restricted α-proteobacterium, ‛Candidatus Liberibacter asiaticus’. This bacterium is primarily transmitted by the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae). Most animal pathogens are considered pathogenic to their insect vectors, whereas the relationships between plant pathogens and their insect vectors are variable. Lately, the relationship of ‛Ca. L. asiaticus’ with its insect vector, D. citri was well investigated at the molecular, biochemical, and biological levels in many studies. Herein, the findings concerning this relationship are discussed and molecular features of the acquisition of ‛Ca. L. asiaticus’ from the plant host and its growth and circulation within D. citri, as well as its transmission to plants, are presented. In addition, the effects of ‛Ca. L. asiaticus’ on the energy metabolism (respiration, TCA cycle, the ATP production), metabolic pathways, immune system, endosymbionts, and detoxification enzymes of D. citri are discussed together with other impacts such as shorter lifespan, altered feeding behavior, and higher fecundity. Overall, although ‛Ca. L. asiaticus’ has significant negative effects on its insect vector, it increases its vector fitness, indicating that it develops a mutualistic relationship with its vector. This review will help in understanding the specific interactions between ‛Ca. L. asiaticus’ and its psyllid vector in order to design innovative management strategies.

scholarly journals Lessons from One Fastidious Bacterium to Another: What Can We Learn about Liberibacter Species from Xylella fastidiosa

Insects ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 300 ◽  
Author(s):  
Angela Kruse ◽  
Laura A. Fleites ◽  
Michelle Heck
Keyword(s):  
Control Strategies ◽  
Xylella Fastidiosa ◽  
Historical Context ◽  
Control Plant ◽  
Bacterial Pathogen ◽  
Pathogen Transmission ◽  
Control Measures ◽  
Insect Vector ◽  
Potential Applicability ◽  
Candidatus Liberibacter

Huanglongbing is causing economic devastation to the citrus industry in Florida, and threatens the industry everywhere the bacterial pathogens in the Candidatus Liberibacter genus and their insect vectors are found. Bacteria in the genus cannot be cultured and no durable strategy is available for growers to control plant infection or pathogen transmission. However, scientists and grape growers were once in a comparable situation after the emergence of Pierce’s disease, which is caused by Xylella fastidiosa and spread by its hemipteran insect vector. Proactive quarantine and vector control measures coupled with interdisciplinary data-driven science established control of this devastating disease and pushed the frontiers of knowledge in the plant pathology and vector biology fields. Our review highlights the successful strategies used to understand and control X. fastidiosa and their potential applicability to the liberibacters associated with citrus greening, with a focus on the interactions between bacterial pathogen and insect vector. By placing the study of Candidatus Liberibacter spp. within the current and historical context of another fastidious emergent plant pathogen, future basic and applied research to develop control strategies can be prioritized.

scholarly journals Candidatus Phytoplasma solani (Stolbur phytoplasma).

2021 ◽  
Author(s):  
Fabio Quaglino
Keyword(s):  
Host Plants ◽  
Pathogenic Bacteria ◽  
Eastern Mediterranean ◽  
Control Strategies ◽  
Mediterranean Area ◽  
Plant Diseases ◽  
Cultivated Plants ◽  
Insect Vector ◽  
Insect Vectors ◽  
The European Union

Abstract Phytoplasmas are cell-wall-less plant pathogenic bacteria of the class Mollicutes, which inhabit the phloem sieve tubes of plants and have been associated with several hundred diseases affecting economically important crops. Over the past few decades 'Candidatus Phytoplasma solani', belonging to the 16SrXII-A ribosomal subgroup, has been found to cause a range of plant diseases in different agro-ecosystems in many countries in Europe and the eastern Mediterranean area and a number of others all over the world. It is thought likely that it has always been present, at least in its European range, but has only been noticed in recent years. Diseases caused include bois noir in grapevines, stolbur in tomatoes, potatoes and other wild and cultivated plants, maize redness, lavender decline, and yellowing, reddening, decline, dwarfism, leaf malformation and degeneration diseases of other plants. 'Ca. P. solani' is usually transmitted from plant to plant by the polyphagous insect vector Hyalesthes obsoletus (Cixiidae) which, although it can complete its life cycle on only a small number of plant species, feeds on a much wider range. Recent studies have demonstrated the presence of additional insect vectors of this phytoplasma in Europe, such as Reptalus panzeri in Serbia, possibly R. quinquecostatus in Serbia and France, and Anaceratagallia ribauti in Austria. This scenario highlights the extreme complexity of the ecology of both 'Ca. Phytoplasma solani' and its insect vectors, underlying the difficulty in studying the epidemiology of diseases associated with this pathogen and in developing efficient control strategies. 'Ca. Phytoplasma solani' is also transmitted by parasitic plants and by grafting and vegetative propagation of infected host plants; it can be spread when host plants are transported by people. In the European Union it is listed as a harmful organism necessitating restrictions on the import of plants in the family Solanaceae.

scholarly journals Blocking the Transmission of a Noncirculative Vector-Borne Plant Pathogenic Bacterium

2016 ◽  
Vol 29 (7) ◽  
pp. 535-544 ◽  
Author(s):  
Fabien Labroussaa ◽  
Adam R. Zeilinger ◽  
Rodrigo P. P. Almeida
Keyword(s):  
Cell Adhesion ◽  
Plant Pathogens ◽  
Control Strategies ◽  
Hypothetical Protein ◽  
Insect Vector ◽  
Bacterial Populations ◽  
Vector Borne Diseases ◽  
Nontarget Effects ◽  
Vector Borne

The successful control of insect-borne plant pathogens is often difficult to achieve due to the ecologically complex interactions among pathogens, vectors, and host plants. Disease management often relies on pesticides and other approaches that have limited long-term sustainability. To add a new tool to control vector-borne diseases, we attempted to block the transmission of a bacterial insect-transmitted pathogen, the bacterium Xylella fastidiosa, by disrupting bacteria–insect vector interactions. X. fastidiosa is known to attach to and colonize the cuticular surface of the mouthparts of vectors; a set of recombinant peptides was generated and the chemical affinities of these peptides to chitin and related carbohydrates was assayed in vitro. Two candidates, the X. fastidiosa hypothetical protein PD1764 and an N-terminal region of the hemagglutinin-like protein B (HxfB) showed affinity for these substrates. These proteins were provided to vectors via an artificial diet system in which insects acquire X. fastidiosa, followed by an inoculation access period on plants under greenhouse conditions. Both PD1764 and HxfAD1-3 significantly blocked transmission. Furthermore, bacterial populations within insects over a 10-day period demonstrated that these peptides inhibited cell adhesion to vectors but not bacterial multiplication, indicating that the mode of action of these peptides is restricted to limiting cell adhesion to insects, likely via competition for adhesion sites. These results open a new venue in the search for sustainable disease-control strategies that are pathogen specific and may have limited nontarget effects.

scholarly journals Marine Organisms for the Sustainable Management of Plant Parasitic Nematodes

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 369
Author(s):  
Pasqua Veronico ◽  
Maria Teresa Melillo
Keyword(s):  
Crop Production ◽  
Control Strategies ◽  
Marine Organisms ◽  
New Drugs ◽  
Effective Control ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Wide Range ◽  
Plant Growth Stimulants ◽  
Plant Parasitic

Plant parasitic nematodes are annually responsible for the loss of 10%–25% of worldwide crop production, most of which is attributable to root-knot nematodes (RKNs) that infest a wide range of agricultural crops throughout the world. Current nematode control tools are not enough to ensure the effective management of these parasites, mainly due to the severe restrictions imposed on the use of chemical pesticides. Therefore, it is important to discover new potential nematicidal sources that are suitable for the development of additional safe and effective control strategies. In the last few decades, there has been an explosion of information about the use of seaweeds as plant growth stimulants and potential nematicides. Novel bioactive compounds have been isolated from marine cyanobacteria and sponges in an effort to find their application outside marine ecosystems and in the discovery of new drugs. Their potential as antihelmintics could also be exploited to find applicability against plant parasitic nematodes. The present review focuses on the activity of marine organisms on RKNs and their potential application as safe nematicidal agents.

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