scholarly journals Towards the validation of high-throughput sequencing (HTS) for routine plant virus diagnostics: measurement of variation linked to HTS detection of citrus viruses and viroids

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Rachelle Bester ◽  
Glynnis Cook ◽  
Johannes H. J. Breytenbach ◽  
Chanel Steyn ◽  
Rochelle De Bruyn ◽  
...  

Abstract Background High-throughput sequencing (HTS) has been applied successfully for virus and viroid discovery in many agricultural crops leading to the current drive to apply this technology in routine pathogen detection. The validation of HTS-based pathogen detection is therefore paramount. Methods Plant infections were established by graft inoculating a suite of viruses and viroids from established sources for further study. Four plants (one healthy plant and three infected) were sampled in triplicate and total RNA was extracted using two different methods (CTAB extraction protocol and the Zymo Research Quick-RNA Plant Miniprep Kit) and sent for Illumina HTS. One replicate sample of each plant for each RNA extraction method was also sent for HTS on an Ion Torrent platform. The data were evaluated for biological and technical variation focussing on RNA extraction method, platform used and bioinformatic analysis. Results The study evaluated the influence of different HTS protocols on the sensitivity, specificity and repeatability of HTS as a detection tool. Both extraction methods and sequencing platforms resulted in significant differences between the data sets. Using a de novo assembly approach, complemented with read mapping, the Illumina data allowed a greater proportion of the expected pathogen scaffolds to be inferred, and an accurate virome profile was constructed. The complete virome profile was also constructed using the Ion Torrent data but analyses showed that more sequencing depth is required to be comparative to the Illumina protocol and produce consistent results. The CTAB extraction protocol lowered the proportion of viroid sequences recovered with HTS, and the Zymo Research kit resulted in more variation in the read counts obtained per pathogen sequence. The expression profiles of reference genes were also investigated to assess the suitability of these genes as internal controls to allow for the comparison between samples across different protocols. Conclusions This study highlights the need to measure the level of variation that can arise from the different variables of an HTS protocol, from sample preparation to data analysis. HTS is more comprehensive than any assay previously used, but with the necessary validations and standard operating procedures, the implementation of HTS as part of routine pathogen screening practices is possible.

2016 ◽  
Vol 106 (5) ◽  
pp. 519-527 ◽  
Author(s):  
D. E. V. Villamor ◽  
T. A. Mekuria ◽  
S. S. Pillai ◽  
K. C. Eastwell

Recent studies have shown the superiority of high-throughput sequencing (HTS) technology over many standard protocols for pathogen detection. HTS was initiated on fruit tree accessions from disparate sources to improve and advance virus-testing procedures. A virus with genomic features resembling most closely that of the recently described Nectarine stem-pitting-associated virus, putative member of genus Luteovirus, was found in three nectarine trees (Prunus persica cv. nectarina), each exhibiting stem-pitting symptoms on the woody cylinder above the graft union. In these samples, HTS also revealed the presence of a coinfecting virus with genome characteristics typical of members of the genus Marafivirus. The same marafivirus- and luteovirus-like viruses were detected in nonsymptomatic nectarine and peach selections, indicating only a loose relationship between these two viruses with nectarine stem-pitting disease symptoms. Two selections infected with each of these viruses had previously tested free of known virus or virus-like agents using the current biological, serological, and molecular tests employed at the Clean Plant Center Northwest. Overall, this study presents the characterization by HTS of novel marafivirus- and luteovirus-like viruses of nectarine, and provides further insights into the etiology of nectarine stem-pitting disease. The discovery of these new viruses emphasizes the ability of HTS to reveal viruses that are not detected by existing protocols.


Genes ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 30
Author(s):  
Yaodong Zhao ◽  
Wenjing Ma ◽  
Xiaohong Wei ◽  
Yu Long ◽  
Ying Zhao ◽  
...  

Alfalfa (Medicago sativa L.) is a high quality leguminous forage. Drought stress is one of the main factors that restrict the development of the alfalfa industry. High-throughput sequencing was used to analyze the microRNA (miRNA) profiles of alfalfa plants treated with CK (normal water), PEG (polyethylene glycol-6000; drought stress), and PEG + SNP (sodium nitroprusside; nitric oxide (NO) sprayed externally under drought stress). We identified 90 known miRNAs belonging to 46 families and predicted 177 new miRNAs. Real-time quantitative fluorescent PCR (qRT-PCR) was used to validate high-throughput expression analysis data. A total of 32 (14 known miRNAs and 18 new miRNAs) and 55 (24 known miRNAs and 31 new miRNAs) differentially expressed miRNAs were identified in PEG and PEG + SNP samples. This suggested that exogenous NO can induce more new miRNAs. The differentially expressed miRNA maturation sequences in the two treatment groups were targeted by 86 and 157 potential target genes, separately. The function of target genes was annotated by gene ontology (GO) enrichment and kyoto encyclopedia of genes and genomes (KEGG) analysis. The expression profiles of nine selected miRNAs and their target genes verified that their expression patterns were opposite. This study has documented that analysis of miRNA under PEG and PEG + SNP conditions provides important insights into the improvement of drought resistance of alfalfa by exogenous NO at the molecular level. This has important scientific value and practical significance for the improvement of plant drought resistance by exogenous NO.


2011 ◽  
Vol 17 (2) ◽  
pp. 241-244 ◽  
Author(s):  
H. Yongfeng ◽  
Y. Fan ◽  
D. Jie ◽  
Y. Jian ◽  
Z. Ting ◽  
...  

2019 ◽  
Vol 63 (4) ◽  
pp. 471-479
Author(s):  
Anna Orłowska ◽  
Ewelina Iwan ◽  
Marcin Smreczak ◽  
Jerzy Rola

AbstractIntroductionHigh-throughput sequencing (HTS) identifies random viral fragments in environmental samples metagenomically. High reliability gains it broad application in virus evolution, host-virus interaction, and pathogenicity studies. Deep sequencing of field samples with content of host genetic material and bacteria often produces insufficient data for metagenomics and must be preceded by target enrichment. The main goal of the study was the evaluation of HTS for complete genome sequencing of field-case rabies viruses (RABVs).Material and MethodsThe material was 23 RABVs isolated mainly from red foxes and one European bat lyssavirus-1 isolate propagated in neuroblastoma cells. Three methods of RNA isolation were tested for the direct metagenomics and RABV-enriched approaches. Deep sequencing was performed with a MiSeq sequencer (Illumina) and reagent v3 kit. Bioinformatics data were evaluated by Kraken and Centrifuge software and de novo assembly was done with metaSPAdes.ResultsTesting RNA extraction procedures revealed the deep sequencing scope superiority of the combined TRIzol/column method. This HTS methodology made it possible to obtain complete genomes of all the RABV isolates collected in the field. Significantly greater rates of RABV genome coverages (over 5,900) were obtained with RABV enrichment. Direct metagenomic studies sequenced the full length of 6 out of 16 RABV isolates with a medium coverage between 1 and 71.ConclusionDirect metagenomics gives the most realistic illustration of the field sample microbiome, but with low coverage. For deep characterisation of viruses, e.g. for spatial and temporal phylogeography during outbreaks, target enrichment is recommended as it covers sequences much more completely.


2019 ◽  
Vol 10 ◽  
Author(s):  
Ana Cláudia Silva ◽  
Virginia Ruiz-Ferrer ◽  
Ángela Martínez-Gómez ◽  
Marta Barcala ◽  
Carmen Fenoll ◽  
...  

2020 ◽  
Author(s):  
Justin P. Shaffer ◽  
Clarisse Marotz ◽  
Pedro Belda-Ferre ◽  
Cameron Martino ◽  
Stephen Wandro ◽  
...  

AbstractOne goal among microbial ecology researchers is to capture the maximum amount of information from all organisms in a sample. The recent COVID-19 pandemic, caused by the RNA virus SARS-CoV-2, has highlighted a gap in traditional DNA-based protocols, including the high-throughput methods we previously established as field standards. To enable simultaneous SARS-CoV-2 and microbial community profiling, we compare the relative performance of two total nucleic acid extraction protocols and our previously benchmarked protocol. We included a diverse panel of environmental and host-associated sample types, including body sites commonly swabbed for COVID-19 testing. Here we present results comparing the cost, processing time, DNA and RNA yield, microbial community composition, limit of detection, and well-to-well contamination, between these protocols.Accession numbersRaw sequence data were deposited at the European Nucleotide Archive (accession#: ERP124610) and raw and processed data are available at Qiita (Study ID: 12201). All processing and analysis code is available on GitHub (github.com/justinshaffer/Extraction_test_MagMAX).Methods summaryTo allow for downstream applications involving RNA-based organisms such as SARS-CoV-2, we compared the two extraction protocols designed to extract DNA and RNA against our previously established protocol for extracting only DNA for microbial community analyses. Across 10 diverse sample types, one of the two protocols was equivalent or better than our established DNA-based protocol. Our conclusion is based on per-sample comparisons of DNA and RNA yield, the number of quality sequences generated, microbial community alpha- and beta-diversity and taxonomic composition, the limit of detection, and extent of well-to-well contamination.


2020 ◽  
Author(s):  
santiago vilanova ◽  
David Alonso ◽  
Pietro Gramazio ◽  
Mariola Plazas ◽  
Edgar Garcia Fortea ◽  
...  

Abstract Background The use of sequencing and genotyping platforms has undergone dramatic improvements, enabling the generation of a wealth of genomic information. Despite this progress, the availability of high-quality genomic DNA (gDNA) in sufficient concentrations is often a main limitation, especially for third-generation sequencing platforms. A variety of DNA extraction methods and commercial kits are available. However, many of these are costly and frequently give either low yield or low-quality DNA, inappropriate for next generation sequencing (NGS) platforms. Here, we describe a fast and inexpensive DNA extraction method (SILEX) applicable to a wide range of plant species and tissues. Results SILEX is a high-throughput DNA extraction protocol, based on the standard CTAB method with a DNA silica matrix recovery, which allows obtaining NGS-quality high molecular weight genomic plant DNA free of inhibitory compounds. SILEX was compared with a standard CTAB extraction protocol and a common commercial extraction kit in a variety of species, including recalcitrant ones, from different families. In comparison with the other methods, SILEX yielded DNA in higher concentrations and of higher quality. Manual extraction of 48 samples can be done in 96 min by one person at a cost of 0.12 €/sample of reagents and consumables. Hundreds of tomato gDNA samples obtained with either SILEX or the commercial kit were successfully genotyped with Single Primer Enrichment Technology (SPET) with the Illumina HiSeq 2500 platform. Furthermore, DNA extracted from Solanum elaeagnifolium using this protocol was assessed by Pulsed-field gel electrophoresis (PFGE), obtaining a suitable size ranges for most sequencing platforms that required high-molecular-weight DNA such as Nanopore or PacBio. Conclusions A high-throughput, fast and inexpensive DNA extraction protocol was developed and validated for a wide variety of plants and tissues. SILEX offers an easy, scalable, efficient and inexpensive way to extract DNA for various next-generation sequencing applications including SPET and Nanopore among others.


2012 ◽  
Vol 24 (1) ◽  
pp. 184 ◽  
Author(s):  
S. C. Isom ◽  
J. R. Stevens ◽  
R. Li ◽  
L. D. Spate ◽  
W. G. Spollen ◽  
...  

Significant embryo mortality occurs at or around the time of implantation or attachment in virtually all mammalian species studied to date, even in naturally conceived embryos. Embryos resulting from assisted reproductive technologies (ART) are even more susceptible to peri-implantation failure. Herein we describe our effort to characterise the transcriptomes of embryonic disc (ED) and trophoblast (TE) cells from porcine embryos derived from AI, IVF, parthenogenetic oocyte activation (PA) and somatic cell nuclear transfer (NT) on Days 10, 12 and 14 of gestation. The IVF, PA and somatic cell NT embryos were generated using in vitro–matured oocytes, cultured overnight in vitro and then transferred at the 1- to 2-cell stage into appropriately synchronized recipient gilts. On the appropriate collection day, embryos were flushed from the uterus and ED was separated from TE by mechanical dissection. Double-stranded cDNA from the collected samples was sequenced using the GAII platform from Illumina (San Diego, CA, USA). The resulting sequencing reads were aligned to a custom swine transcriptome database (see Isom et al. 2010). A generalized linear model was fit for each of 41 693 genomic regions, for ED and TE samples separately, accounting for embryo type, gestation day and their interaction and using total lane read count as a normalizing offset. Genes with significant embryo type differences (controlling the false discovery rate at 0.10) were subsequently tested for differences between IVF and each of AI, PA and NT. Those genes with significant post hoc differences (either up- or down-regulated compared with IVF) were characterised in terms of gene ontologies and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways using a gene set enrichment test. Bone morphogenetic protein signalling was down-regulated (KEGG; P = 0.0099; adjusted to control for FDR at 0.05) in the ED of IVF embryos when compared with AI embryos. In TE cells from IVF embryos, ubiquitin-mediated proteolysis and ErbB signalling (adj P = 0.031 for both pathways) were aberrantly regulated when compared with AI embryos. Of particular interest is the observation that expression of genes involved in chromatin modification (GO:BiologicalProcess; q-value = 0.00005) and epigenetic regulation of transcription (q = 0.00007) was very significantly disrupted in inner cell mass cells from NT embryos compared with IVF embryos. Surprisingly, no such disruption of the epigenetic machinery was observed in the TE cells from NT embryos. In summary, we have used high-throughput sequencing technologies to compare gene expression profiles of various ART embryo types during peri-implantation development. We expect that these data will provide important insight into the root causes of (and possible opportunities for mitigation of) suboptimal development of embryos derived from ART. Funding was received from NIH R01 RR013438 and Food for the 21st Century (RSP) and the Utah Agricultural Experiment Station (UTA00151 and UTA00560 for S. C. Isom and J. R. Stevens, respectively).


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