Improving grapevine virus diagnostics: Comparative analysis of three dsRNA enrichment methods for high-throughput sequencing.

The extraction of double stranded (ds) RNA is a common enrichment method for the study, characterization, and detection of RNA viruses. In addition to RNA viruses, viroids, and some DNA viruses, can also be detected from dsRNA enriched extracts which makes it an attractive method for detecting a wide range of viruses when coupled with HTS. Several dsRNA enrichment strategies have been developed. The oldest utilizes the selective binding properties of dsRNA to cellulose. More recent methods are based on the application of anti-dsRNA antibodies and viral proteins with a specific affinity for dsRNA. All three methods have been used together with HTS for plant virus detection and study. To our knowledge, this is the first comparative study of three alternative dsRNA enrichment methods for virus and viroid detection through HTS using virus-infected, and healthy grapevine test plants. Extracts were performed in triplicate using methods based on, the anti-dsRNA antibody mAb rJ2 (Millipore Sigma Canada Ltd, Oakville, ON, Canada), the B2 dsRNA binding protein, and ReliaPrep™ Resin (Promega Corporation, Madison, WI, USA). The results show that the workflows for all three methods are effectively comparable, apart from purification steps related to antibody and binding protein construct. Both the cellulose resin and dsRNA binding protein construct methods provide highly enriched dsRNA extracts suitable for HTS with the B2 method providing a 36× and the ReliaPrep™ Resin a 163× increase in dsRNA enrichment compared to the mAb rJ2 antibody. The overall consistency and cost effectiveness of the ReliaPrep™ cellulose resin-based method and the potentially simpler adaptation to robotics made it the method of choice for future transfer to a semi-automated workflow.

Area Wide Monitoring of Plant and Honey Bee (Apis mellifera) Viruses in Blueberry (Vaccinium corymbosum) Agroecosystems Facilitated by Honey Bee Pollination.

Healthy agroecosystems are dependent on a complex web of factors and inter-species interactions. Flowers are hubs for pathogen transmission, including the horizontal or vertical transmission of plant-viruses and the horizontal transmission of bee-viruses. Pollination by the European honey bee (Apis mellifera) is critical for industrial fruit production, but bees can also vector viruses and other pathogens between individuals. Here, we utilized commercial honey bee pollination services in blueberry (Vaccinium corymbosum) farms for a metagenomics-based bee and plant virus monitoring system. Following RNA sequencing, viruses were identified by mapping reads to a reference sequence database through the bioinformatics portal Virtool. In total, 29 unique plant viral species were found at two blueberry farms in British Columbia (BC). Nine viruses were identified at one site in Ontario (ON), five of which were not identified in BC. Ilarviruses blueberry shock virus (BlShV) and prune dwarf virus (PDV) were the most frequently detected viruses in BC but absent in ON, while nepoviruses tomato ringspot virus and tobacco ringspot virus were common in ON but absent in BC. BlShV coat protein (CP) nucleotide sequences were nearly identical in all samples, while PDV CP sequences were more diverse, suggesting multiple strains of PDV circulating at this site. Ten bee-infecting viruses were identified, with black queen cell virus frequently detected in ON and BC. Area-wide bee-mediated pathogen monitoring can provide new insights into the diversity of viruses present in, and the health of, bee-pollination ecosystems. This approach can be limited by a short sampling season, biased towards pollen-transmitted viruses, and the plant material collected by bees can be very diverse. This can obscure the origin of some viruses, but bee-mediated virus monitoring can be an effective preliminary monitoring approach.

Choosing wisely: A prospective study of direct to operating room trauma resuscitation including real-time trauma surgeon after-action review.

INTRODUCTION: Although several centers have direct to operating room (DOR) resuscitation programs, there are no published prospective studies on optimal patient selection, interventions, outcomes, or real-time surgeon assessments. METHODS: Direct to operating room cases for 1 year were prospectively enrolled. Demographics, injury types/severity, triage criteria, interventions, and outcomes including Glasgow Outcome Scale score were collected. Detailed time-to-event and sequence data on initial lifesaving interventions (LSIs) or emergent surgeries were analyzed. A structured real-time attending surgeon assessment tool for each case was collected. Direct to operating room activation criteria were grouped into categories: mechanism, physiology, injury pattern, or emergency medical services (EMS) suspicion. RESULTS: There were 104 DOR cases: male, 84%; penetrating, 80%; and severely injured (Injury Severity Score, >15), 39%. The majority (65%) required at least one LSI (median of 7 minutes from arrival), and 41% underwent immediate emergent surgery (median, 26 minutes). Blunt patients were more severely injured and more likely to undergo LSI (86% vs. 59%) but less likely to require emergent surgery (19% vs. 47%, all p < 0.05). Analysis of DOR criteria categories showed unique patterns in each group for interventions and outcomes, with EMS suspicion associated with the lowest need for DOR. Surgeon assessment tool results found that DOR was indicated in 84% and improved care in 63%, with a small subset identified (9%) where DOR had a negative impact. CONCLUSION: Direct to operating room resuscitation facilitated timely emergent interventions in penetrating truncal trauma and a select subset of critically ill blunt patients. Unique intervention/outcome profiles were identified by activation criteria groups, with little utility among activations for EMS suspicion. Real-time surgeon assessment tool identified high- and low-yield DOR groups. LEVEL OF EVIDENCE: Prospective observational study, level III.

Into the wild and on to the table: A Western Trauma Association multicenter analysis and comparison of wilderness falls in rock climbers and nonclimbers.

BACKGROUND: Wilderness activities expose outdoor enthusiasts to austere environments with injury potential, including falls from height. The majority of published data on falls while climbing or hiking are from emergency departments. We sought to more accurately describe the injury pattern of wilderness falls that lead to serious injury requiring trauma center evaluation and to further distinguish climbing as a unique pattern of injury. METHODS: Data were collected from 17 centers in 11 states on all wilderness falls (fall from cliff: International Classification of Diseases, Ninth Revision, e884.1; International Classification of Diseases, 10th Revision, w15.xx) from 2006 to 2018 as a Western Trauma Association multicenter investigation. Demographics, injury characteristics, and care delivery were analyzed. Comparative analyses were performed for climbing versus nonclimbing mechanisms. RESULTS: Over the 13-year study period, 1,176 wilderness fall victims were analyzed (301 climbers, 875 nonclimbers). Fall victims were male (76%), young (33 years), and moderately injured (Injury Severity Score, 12.8). Average fall height was 48 ft, and average rescue/transport time was 4 hours. Nineteen percent were intoxicated. The most common injury regions were soft tissue (57%), lower extremity (47%), head (40%), and spine (36%). Nonclimbers had a higher incidence of severe head and facial injuries despite having equivalent overall Injury Severity Score. On multivariate analysis, climbing remained independently associated with increased need for surgery but lower odds of composite intensive care unit admission/death. Contrary to studies of urban falls, height of fall in wilderness falls was not independently associated with mortality or Injury Severity Score. CONCLUSION: Wilderness falls represent a unique population with distinct patterns of predominantly soft tissue, head, and lower extremity injury. Climbers are younger, usually male, more often discharged home, and require more surgery but less critical care. LEVEL OF EVIDENCE: Epidemiological, Level IV.

Direct to operating room trauma resuscitation: Optimizing patient selection and time-critical outcomes when minutes count.

BACKGROUND: Although several trauma centers have developed direct to operating room (DOR) trauma resuscitation programs, there is little published data on optimal patient selection, practices, and outcomes. We sought to analyze triage criteria and interventions associated with optimal DOR outcomes and resource utilization. METHODS: Retrospective review of all adult DOR resuscitations for a 6-year period was performed. Triage criteria were analyzed individually and grouped into categories: mechanism, physiology, anatomy/injury, or other. The best univariate and multivariate predictors of requiring lifesaving interventions (LSIs) or emergent surgery (ES) were analyzed. Actual and predicted mortality were compared for all patients and for predefined time-sensitive subgroups. RESULTS: There were 628 DOR patients (5% of all admissions) identified; the majority were male (79%), penetrating mechanism (70%), severely injured (40% ISS >15), and 17% died. Half of patients required LSI and 23% required ES, with significantly greater need for ES and lower need for LSI after penetrating versus blunt injury (p < 0.01). Although injury mechanism criteria triggered most DOR cases and best predicted need for ES, the physiology and anatomy/injury criteria were associated with greater need for LSI and mortality. Observed mortality was significantly lower than predicted mortality with DOR for several key subgroups. Triage schemes for both ES and LSI could be simplified to four to six independent predictors by regression analysis. CONCLUSION: The DOR program identified severely injured trauma patients at increased risk for requiring LSI and/or ES. Different triage variable categories drive the need for ES versus LSI and could be simplified or optimized based on local needs or preferences. Direct to operating room was associated with better than expected survival among specific time-sensitive subgroups. LEVEL OF EVIDENCE: Therapeutic/Care Management, Level IV.

Discovery of Negative-Sense RNA Viruses in Trees Infected with Apple Rubbery Wood Disease by Next-Generation Sequencing.

Apple rubbery wood is a disease of apple found around the world, often associated with Apple flat limb disease, and regulated in many countries. Despite its long history in apple cultivation, the disease's causal agent has remained elusive. In this study, next-generation sequencing (NGS) was used to identify and characterize several related novel viral agents from apple rubbery wood-infected plants, which have been named Apple rubbery wood virus (ARWV) 1 and 2. Additional specimens with apple rubbery wood disease tested positive by polymerase chain reaction with primers designed to ARWV 1 and 2 genomic RNA segments. In an NGS-based screening of over 100 Malus and 100 Prunus specimens from a collection of virus-infected trees, only one Malus specimen was found to be infected with ARWV not known to be infected with the disease, which strongly suggests that ARWV is not commonly found in Malus spp. or other fruit trees. The two viruses are most closely related to members of the order Bunyavirales. Three RNA segments (large, medium, and small) were characterized and the viruses likely represent a new genus under the family Phenuiviridae, with a suggested name of Rubodvirus (Rubbery wood virus).

Comparative analysis of cherry virus A genome sequences assembled from deep sequencing data.

Cherry virus A (CVA) is a ubiquitous graft-transmissible virus that mainly infects Prunus spp. Next-generation sequencing was applied to 39 tree fruit specimens infected with CVA, and 75 full and 16 partial-length CVA genome sequences were assembled. Phylogenetic analysis of these and 11 previously sequenced CVA genomes resulted in six major clusters with no observable relationship between the host and the assembled genome sequences. Recombination analysis detected four recombinants. Consistent single-nucleotide polymorphism (SNP) patterns were observed between the 75 full-length genomes and their sequence clouds, which supports a quasispecies model for CVA evolution.

Screening for plant viruses by next generation sequencing using a modified double strand RNA extraction protocol with an internal amplification control.

The majority of plant viruses contain RNA genomes. Detection of viral RNA genomes in infected plant material by next generation sequencing (NGS) is possible through the extraction and sequencing of total RNA, total RNA devoid of ribosomal RNA, small RNA interference (RNAi) molecules, or double stranded RNA (dsRNA). Plants do not typically produce high molecular weight dsRNA, therefore the presence of dsRNA makes it an attractive target for plant virus diagnostics. The sensitivity of NGS as a diagnostic method demands an effective dsRNA protocol that is both representative of the sample and minimizes sample cross contamination. We have developed a modified dsRNA extraction protocol that is more efficient compared to traditional protocols, requiring reduced amounts of starting material, that is less prone to sample cross contamination. This was accomplished by using bead based homogenization of plant material in closed, disposable 50ml tubes. To assess the quality of extraction, we also developed an internal control by designing a real-time (quantitative) PCR (qPCR) assay that targets endornaviruses present in Phaseolus vulgaris cultivar Black Turtle Soup (BTS).

The genome of the yellow potato cyst nematode, Globodera rostochiensis, reveals insights into the basis of parasitism and virulence.

BACKGROUND: The yellow potato cyst nematode, Globodera rostochiensis, is a devastating plant pathogen of global economic importance. This biotrophic parasite secretes effectors from pharyngeal glands, some of which were acquired by horizontal gene transfer, to manipulate host processes and promote parasitism. G. rostochiensis is classified into pathotypes with different plant resistance-breaking phenotypes. RESULTS: We generate a high quality genome assembly for G. rostochiensis pathotype Ro1, identify putative effectors and horizontal gene transfer events, map gene expression through the life cycle focusing on key parasitic transitions and sequence the genomes of eight populations including four additional pathotypes to identify variation. Horizontal gene transfer contributes 3.5 % of the predicted genes, of which approximately 8.5 % are deployed as effectors. Over one-third of all effector genes are clustered in 21 putative 'effector islands' in the genome. We identify a dorsal gland promoter element motif (termed DOG Box) present upstream in representatives from 26 out of 28 dorsal gland effector families, and predict a putative effector superset associated with this motif. We validate gland cell expression in two novel genes by in situ hybridisation and catalogue dorsal gland promoter element-containing effectors from available cyst nematode genomes. Comparison of effector diversity between pathotypes highlights correlation with plant resistance-breaking. CONCLUSIONS: These G. rostochiensis genome resources will facilitate major advances in understanding nematode plant-parasitism. Dorsal gland promoter element-containing effectors are at the front line of the evolutionary arms race between plant and parasite and the ability to predict gland cell expression a priori promises rapid advances in understanding their roles and mechanisms of action.

Complete genome sequence of three tomato ringspot virus isolates: evidence for reassortment and recombination.

The genome sequence of tomato ringspot virus (ToRSV, a subgroup C nepovirus) is currently available for one raspberry isolate. In this study, we describe the complete genome sequence of three additional isolates from raspberry (Rasp1-2014), grapevine (GYV-2014) and prunus (13C280). The degree of nucleotide sequence identity shared between RNA1 and RNA2 in the 5'-terminal 900 nucleotides and 3' untranslated region varied from 98-99 % (13C280, GYV-2014) to 80 % (Rasp1-2014). Phylogenetic studies revealed distinct origins for Rasp1-2014 RNA1 and RNA2, suggesting reassortment. Two recombination events were also identified in the 3' UTR and 5'-terminal region of RNA1.

Amplification-free detection of grapevine viruses using an oligonucleotide microarray.

A single-colour microarray hybridization system was designed and evaluated for the detection of viruses infecting grapevine. Total RNA (≥0.5µg) from infected plants was converted to cDNA and labelled with Cy3 using two different strategies. While amine-modified and labelled cDNA was adequate for the detection of nepoviruses, the 3DNA technique, a post-hybridization detection method that uses intensely fluorescent dendrimer reagents, was required for the detection of closteroviruses in infected plants. Threshold detection levels were based on the ratio between viral specific and 18S rRNA positive control signal intensities. Oligonucleotides between 27 and 75 nucleotides in length were evaluated and compared. Viruses detected include eight nepoviruses, two vitiviruses, and one each of closterovirus, foveavirus, ampelovirus, maculavirus and sadwavirus. Results of this work demonstrate the potential of microarray technique to detect viral pathogens without sequence bias amplification of template RNA.

Occurrence and Detection of Globodera rostochiensis on Vancouver Island, British Columbia: An Update.

The potato cyst nematode (PCN), Globodera rostochiensis, has been present in Central Saanich on Vancouver Island for at least 45 years. Eradication/control efforts have been ongoing, with regulations enacted in the early 1980s restricting the planting of host crops and movement of soil. Surveys monitoring for cyst populations have been minimal since the regulations have been in place with only one limited study in the early 1990s. In this report, a survey of eight fields was undertaken, chosen as the most likely sites that may still harbor viable PCN cysts. Conventional sampling/detection methods were considered inadequate for the detection of very low cyst populations, and an innovative bioassay was developed to improve detection while minimizing costs and labor. Viable cysts were recovered from two fields, both with past quarantine infractions. Fields with no known infractions were found free of viable cysts. Lack of viable cysts found in fields with no infractions suggests that the quarantine restrictions in place since the early 1980s have been effective in reducing or eliminating PCN from these fields. Further systematic and comprehensive retesting of all fields within the quarantine zone is now required, which could lead to the reduction or lifting of some quarantine restrictions.

Detection of genetically modified canola using multiplex PCR coupled with oligonucleotide microarray hybridization.

A rapid method was developed for concurrent screening of transgenic elements in GM canola. This method utilizes a single multiplex PCR coupled with an oligonucleotide DNA array capable of simultaneously detecting the 12 approved GM canola lines in Canada. The assay includes construct-specific elements for identification of approved lines, common elements (e.g., CaMV 35S promoter, Agrobacterium tumefaciens nos terminator, or nptII gene) for screening of approved or unapproved lines, a canola-specific endogenous gene, and endogenous genes from heterologous crops to serve as additional controls. Oligonucleotide probes were validated individually for functionality and specificity by amplification of specific transgene sequences from appropriate GM canola lines corresponding to each probe sequence, and hybridization of amplicons to the array. Each target sequence hybridized to its corresponding oligonucleotide probe and no significant cross-hybridization was observed. The limit of detection was examined for the GM lines GT73, T45, and MS8/RF3, and was determined to be 0.1%, 0.1%, and 0.5%, respectively, well within the European food and feed labeling threshold level of 0.9% for approved GM product. Practically, the method was demonstrated to be effective for the detection of GM canola in several types of animal feed, as well as in commercial canola meal.

Real-time polymerase chain reaction (PCR) quantitative detection of Brassica napus using a locked nucleic acid TaqMan probe.

Several countries have introduced mandatory labeling requirements on foods derived from genetically modified organisms. Real-time quantitative Polymerase Chain Reaction (PCR) has quickly become the method of choice in support of these regulations and requires the development of separate PCR assays targeting the transgenic sequence as well as a specific endogenous gene sequence. To develop a Brassica napus-specific PCR assay, partial sequences of the acetyl-CoA carboxylase BnACCg8 gene from B. napus and the closely related Brassica rapa were determined and compared, and a region of unique nucleotide sequence was identified. Universal amplification primers were designed to either side of this region, and a locked nucleic acid TaqMan probe was designed to the B. napus-specific sequence. Evaluation of this primer/probe combination indicated a high level of specificity to B. napus: no amplification signal was observed with any other species tested, including five closely related Brassica species. The method was assayed with 14 different B. napus cultivars, and comparable amplification curves were consistently obtained for all. The assay was highly sensitive, with a limit of detection between 1 and 10 haploid copies. Practically, the method was demonstrated to be effective for the detection of processed food samples and for the quantification of Roundup Ready canola content in mixed samples.

Detection and quantification of roundup ready soy in foods by conventional and real-time polymerase chain reaction.

Transgenic soybean line GTS-40-3-2, marketed under the trade name Roundup Ready (RR) soy, was developed by Monsanto (USA) to allow for the use of glyphosate, the active ingredient of the herbicide Roundup, as a weed control agent. RR soy was first approved in Canada for environmental release and for feed products in 1995 and later for food products in 1996 and is widely grown in Canada. Consumer concern issues have resulted in proposed labeling regulations in Canada for foods derived from genetically engineered crops. One requirement for labeling is the ability to detect and accurately quantify the amount of transgenic material present in foods. Two assays were evaluated. A conventional qualitative Polymerase Chain Reaction (PCR) assay to detect the presence of soy and RR soy and a real-time PCR to quantify the amount of RR soy present in samples that tested positive in the first assay. PCR controls consisted of certified RR soy reference material, single transgenic soybeans, and a processed food sample containing a known amount of RR soy. To test real-world applicability, a number of common grocery store food items that contain soy-based products were tested. For some samples, significant differences in amplification efficiencies during the quantitative PCR assays were observed compared to the controls, resulting in potentially large errors in quantification. A correction factor was used to try to compensate for these differences.