•The impact of high throughput sequencing in plant virus characterization is summarized.•The potential of high throughput sequencing in plant virus diagnostic is highlighted.•The limitations that ...need to be addressed to achieve this potential are discussed.•Wide adoption of HTS in plant virus diagnostic will require time and specific efforts.
The ability to provide a fast, inexpensive and reliable diagnostic for any given viral infection is a key parameter in efforts to fight and control these ubiquitous pathogens. The recent developments of high-throughput sequencing (also called Next Generation Sequencing – NGS) technologies and bioinformatics have drastically changed the research on viral pathogens. It is now raising a growing interest for virus diagnostics. This review provides a snapshot vision on the current use and impact of high throughput sequencing approaches in plant virus characterization. More specifically, this review highlights the potential of these new technologies and their interplay with current protocols in the future of molecular diagnostic of plant viruses. The current limitations that will need to be addressed for a wider adoption of high-throughput sequencing in plant virus diagnostics are thoroughly discussed.
Gut microbial composition depends on different dietary habits just as health depends on microbial metabolism, but the association of microbiota with different diets in human populations has not yet ...been shown. In this work, we compared the fecal microbiota of European children (EU) and that of children from a rural African village of Burkina Faso (BF), where the diet, high in fiber content, is similar to that of early human settlements at the time of the birth of agriculture. By using high-throughput 16S rDNA sequencing and biochemical analyses, we found significant differences in gut microbiota between the two groups. BF children showed a significant enrichment in Bacteroidetes and depletion in Firmicutes (P < 0.001), with a unique abundance of bacteria from the genus Prevotella and Xylanibacter, known to contain a set of bacterial genes for cellulose and xylan hydrolysis, completely lacking in the EU children. In addition, we found significantly more short-chain fatty acids (P < 0.001) in BF than in EU children. Also, Enterobacteriaceae (Shigella and Escherichia) were significantly underrepresented in BF than in EU children (P < 0.05). We hypothesize that gut microbiota coevolved with the polysaccharide-rich diet of BF individuals, allowing them to maximize energy intake from fibers while also protecting them from inflammations and noninfectious colonic diseases. This study investigates and compares human intestinal microbiota from children characterized by a modern western diet and a rural diet, indicating the importance of preserving this treasure of microbial diversity from ancient rural communities worldwide.
High throughput sequencing technologies accelerated the pace of discovery and identification of new viral species. Nevertheless, biological characterization of a new virus is a complex and long ...process, which can hardly follow the current pace of virus discovery. This review has analyzed 78 publications of new viruses and viroids discovered from 32 fruit tree species since 2011. The scientific biological information useful for a pest risk assessment and published together with the discovery of a new fruit tree virus or viroid has been analyzed. In addition, the 933 publications citing at least one of these original publications were reviewed, focusing on the biology-related information provided. In the original publications, the scientific information provided was the development of a detection test (94%), whole-genome sequence including UTRs (92%), local and large-scale epidemiological surveys (68%), infectivity and indicators experiments (50%), association with symptoms (25%), host range infection (23%), and natural vector identification (8%). The publication of a new virus is cited 2.8 times per year on average. Only 18% of the citations reported information on the biology or geographical repartition of the new viruses. These citing publications improved the new virus characterization by identifying the virus in a new country or continent, determining a new host, developing a new diagnostic test, studying genome or gene diversity, or by studying the transmission. Based on the gathered scientific information on the virus biology, the fulfillment of a recently proposed framework has been evaluated. A baseline prioritization approach for publishing a new plant virus is proposed for proper assessment of the potential risks caused by a newly identified fruit tree virus.
•Host microbiota could interfere with the stability of biocontrol agents once applied.•Microbial community can be favourably shaped to express biocontrol phenotype.•Biocontrol phenotype can be split ...in different metabolic activities.•Helper strains and prebiotics could fill biocontrol metabolic activities.•The timely application of microbial based-products could be revised.
Harvested fruits and vegetables are threatened by pathogens which can cause losses for up to 55 % depending on the fruit and country. A potentially sustainable control method is the biological control of these postharvest diseases using biocontrol agents (BCA). Nevertheless, the lack of reliability in practical conditions compared with synthetic chemical pesticides is a major hinderance. Strategies combining BCA application to nutrient additives, salts, edible coatings, or physical treatments have been evaluated to improve BCA antagonism activity, but with only relative success. The fruit surface is colonized by complex microbial communities that are often resilient. In a such environment, BCA establishment might be difficult. The integration of the role of microbial communities to assemble a BCA-friendly microbiota, is a promising solution to manage the reliability of BCA in real condition. Biocontrol phenotype of a microbiota is a complex metabolic phenotype that can be broken down in a multiple process supported by a network of beneficial microorganisms and molecules. Combining BCA application in a suitable complex biocontrol mix including for example beneficial helper strains, essential macro and micronutrients also acting as prebiotic of biocontrol could help the establishment of BCA in the epiphytic microbial network. At the same time, it could achieve a biocontrol efficacy and reliability comparable to synthetic chemical pesticides. In addition, the timing of beneficial microbial application has been reviewed based on the available literature. For example, we propose that shifting application at flowering stage (to induce a “path dependency”) could be considered for the future management of postharvest disease of fruits and vegetables. This application moment shift could be extended to other plant organ like seeds.
Wheat (
L.) is a staple food of more than 50% of global population.
is the causal agent of sharp eyespot, a devastating disease of cereal crops including wheat. Cutinases produced by fungal pathogens ...play important roles in host-pathogen compatible interactions, but little is known about cutinases in
. In this study, we identified a total of six cutinase encoding genes from
genome, designated as
, analyzed their expression patterns during the infection, and determined virulence role for RcCUT1. All the proteins, RcCUT1-RcCUT6, contain a highly conserved GYSKG motif and another conserved C-x(3)-D-x(2)-C-x(2)-GS-GSD-x(4)-AP-H motif in the carbohydrate esterase 5 domain. The RcCUT1, RcCUT2, RcCUT4, and RcCUT5 are predicted to be secreted proteins containing four cysteine residues. These six cutinase genes had different expression patterns during the fungal infection process to wheat, among which
was highly expressed across all the infection time points but
was not expressed at all and the others were expressed only at certain time points. Further, RcCUT1 was heterologously expressed in
to obtain a purified protein. The purified RcCUT1 was shown to possess the cutinase activity and be able to induce necrosis, H
O
accumulation, and expression of defense-related genes when infiltrated into wheat and
leaves. In contrast, RcCUT1 protein with serine mutation at the first motif had no cutinase activity, consequently lost the ability to induce necrosis. Noticeably, application of the purified RcCUT1 with
led to significantly higher levels of the disease in wheat leaves than application of the fungus alone. These results strongly suggest that RcCUT1 serves as a virulence factor for the fungus. This is the first investigation of the cutinase genes in
and the findings provide an important insight into pathogenesis mechanisms of
on wheat.
Recent advances in high-throughput sequencing technologies and bioinformatics have generated huge new opportunities for discovering and diagnosing plant viruses and viroids. Plant virology has ...undoubtedly benefited from these new methodologies, but at the same time, faces now substantial bottlenecks, namely the biological characterization of the newly discovered viruses and the analysis of their impact at the biosecurity, commercial, regulatory, and scientific levels. This paper proposes a scaled and progressive scientific framework for efficient biological characterization and risk assessment when a previously known or a new plant virus is detected by next generation sequencing (NGS) technologies. Four case studies are also presented to illustrate the need for such a framework, and to discuss the scenarios.
The ecology of plant viruses began to be explored at the end of the 19th century. Since then, major advances have revealed mechanisms of virus-host-vector interactions in various environments. These ...advances have been accelerated by new technlogies for virus detection and characterization, most recently including high throughput sequencing (HTS). HTS allows investigators, for the first time, to characterize all or nearly all viruses in a sample without a priori information about which viruses might be present. This powerful approach has spurred new investigation of the viral metagenome (virome). The rich virome datasets accumulated illuminate important ecological phenomena such as virus spread among host reservoirs (wild and domestic), effects of ecosystem simplification caused by human activities (and agriculture) on the biodiversity and the emergence of new viruses in crops. To be effective, however, HTS-based virome studies must successfully navigate challenges and pitfalls at each procedural step, from plant sampling to library preparation and bioinformatic analyses. This review summarizes major advances in plant virus ecology associated with technological developments, and then presents important considerations and best practices for HTS use in virome studies.
Human intestinal microbiota plays an important role in the maintenance of host health by providing energy, nutrients, and immunological protection. Intestinal dysfunction is a frequent complaint in ...myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients, and previous reports suggest that dysbiosis, i.e. the overgrowth of abnormal populations of bacteria in the gut, is linked to the pathogenesis of the disease.
We used high-throughput 16S rRNA gene sequencing to investigate the presence of specific alterations in the gut microbiota of ME/CFS patients from Belgium and Norway. 43 ME/CFS patients and 36 healthy controls were included in the study. Bacterial DNA was extracted from stool samples, PCR amplification was performed on 16S rRNA gene regions, and PCR amplicons were sequenced using Roche FLX 454 sequencer.
The composition of the gut microbiota was found to differ between Belgian controls and Norwegian controls: Norwegians showed higher percentages of specific Firmicutes populations (Roseburia, Holdemania) and lower proportions of most Bacteroidetes genera. A highly significant separation could be achieved between Norwegian controls and Norwegian patients: patients presented increased proportions of Lactonifactor and Alistipes, as well as a decrease in several Firmicutes populations. In Belgian subjects the patient/control separation was less pronounced, however some abnormalities observed in Norwegian patients were also found in Belgian patients.
These results show that intestinal microbiota is altered in ME/CFS. High-throughput sequencing is a useful tool to diagnose dysbiosis in patients and could help designing treatments based on gut microbiota modulation (antibiotics, pre and probiotics supplementation).
•We looked for alterations of gut microbiota in chronic fatigue syndrome patients.•Patients and controls from two geographical origins were included in the study.•Gut flora composition differed between people from different geographical origins.•Significant alterations of gut microbiota composition were observed in patients.
Phosphorus (P) is the second most important macronutrient for crop growth and a limiting factor in food production. Choosing the right P fertilizer formulation is important for crop production ...systems because P is not mobile in soils, and placing phosphate fertilizers is a major management decision. In addition, root microorganisms play an important role in helping phosphorus fertilization management by regulating soil properties and fertility through different pathways. Our study evaluated the impact of two phosphorous formulations (polyphosphates and orthophosphates) on physiological traits of wheat related to yield (photosynthetic parameters, biomass, and root morphology) and its associated microbiota. A greenhouse experiment was conducted using agricultural soil deficient in P (1.49%). Phenotyping technologies were used at the tillering, stem elongation, heading, flowering, and grain-filling stages. The evaluation of wheat physiological traits revealed highly significant differences between treated and untreated plants but not between phosphorous fertilizers. High-throughput sequencing technologies were applied to analyse the wheat rhizosphere and rhizoplane microbiota at the tillering and the grain-filling growth stages. The alpha- and beta-diversity analyses of bacterial and fungal microbiota revealed differences between fertilized and non-fertilized wheat, rhizosphere, and rhizoplane, and the tillering and grain-filling growth stages. Our study provides new information on the composition of the wheat microbiota in the rhizosphere and rhizoplane during growth stages (Z39 and Z69) under polyphosphate and orthophosphate fertilization. Hence, a deeper understanding of this interaction could provide better insights into managing microbial communities to promote beneficial plant-microbiome interactions for P uptake.
•Metagenomic approach on apple at taxonomic and functional levels.•High fungal and bacterial diversity in the metagenome.•Wide presence of pathogens and some known biocontrol agent species.•Known ...genes involved in biocontrol are carried by potential biocontrol agents.
The epiphytic plant microbial communities living at the surface of fruit have been the source of most current biocontrol agents (BCAs) and can influence fruit quality during storage. Despite this interest, their taxonomical and functional composition has been poorly studied so far. This paper describes the use of high-throughput sequencing (HTS) technologies to characterise the microbial phytobiome residing on apple surface at the taxonomic and functional levels through shotgun metagenome sequencing. Apples from the Pinova cultivar bearing no symptom of disease development were sampled in an orchard at harvest, and their epiphytic microbiota was isolated. After DNA extraction, 14.1 Gbases of raw sequences were generated by HTS. These sequences were annotated following two pipelines in parallel: (i) they were individually analysed by the MG-RAST server, and (ii) they were de novo assembled into contigs and the contigs were annotated by the IMG server. Our results showed a very high fungal and bacterial diversity, with a higher proportion of fungal sequences (79.0%) than bacterial sequences (13.8%). Among fungi, the phylum Ascomycota prevailed, while Bacteroides were dominant in the bacterial population. Among them, 24 species corresponded to known apple pathogens like Aspergillus spp., Botrytis spp., Sclerotinia spp., and Penicillium spp. for fungi, and Erwinia spp. and Agrobacterium spp. for bacteria. Moreover, several contigs were assigned to species of known BCA strains belonging to the following genera: Filobasidiella spp., Talaromyces spp, Candida spp., Saccharomyces spp., Bacillus spp., and Enterobacter spp. The functional analysis showed similar patterns of abundance and function in all samples, identified genes potentially involved in biocontrol properties, but also underlined the complexity of datum interpretation and the incompleteness of current databases.
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