scholarly journals Transcriptome-Wide Comparisons and Virulence Gene Polymorphisms of Host-Associated Genotypes of the Cnidarian Parasite Ceratonova shasta in Salmonids

2020 ◽  
Vol 12 (8) ◽  
pp. 1258-1276 ◽  
Author(s):  
Gema Alama-Bermejo ◽  
Eli Meyer ◽  
Stephen D Atkinson ◽  
Astrid S Holzer ◽  
Monika M Wiśniewska ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
High Throughput Sequencing ◽  
Coho Salmon ◽  
Proteolytic Enzymes ◽  
Evolutionary Relationship ◽  
Model Organism ◽  
Virulence Gene ◽  
Genetic Distances ◽  
Targeted Interventions ◽  
Single Nucleotide Polymorphism Calling

Abstract Ceratonova shasta is an important myxozoan pathogen affecting the health of salmonid fishes in the Pacific Northwest of North America. Ceratonova shasta exists as a complex of host-specific genotypes, some with low to moderate virulence, and one that causes a profound, lethal infection in susceptible hosts. High throughput sequencing methods are powerful tools for discovering the genetic basis of these host/virulence differences, but deep sequencing of myxozoans has been challenging due to extremely fast molecular evolution of this group, yielding strongly divergent sequences that are difficult to identify, and unavoidable host contamination. We designed and optimized different bioinformatic pipelines to address these challenges. We obtained a unique set of comprehensive, host-free myxozoan RNA-seq data from C. shasta genotypes of varying virulence from different salmonid hosts. Analyses of transcriptome-wide genetic distances and maximum likelihood multigene phylogenies elucidated the evolutionary relationship between lineages and demonstrated the limited resolution of the established Internal Transcribed Spacer marker for C. shasta genotype identification, as this marker fails to differentiate between biologically distinct genotype II lineages from coho salmon and rainbow trout. We further analyzed the data sets based on polymorphisms in two gene groups related to virulence: cell migration and proteolytic enzymes including their inhibitors. The developed single-nucleotide polymorphism-calling pipeline identified polymorphisms between genotypes and demonstrated that variations in both motility and protease genes were associated with different levels of virulence of C. shasta in its salmonid hosts. The prospective use of proteolytic enzymes as promising candidates for targeted interventions against myxozoans in aquaculture is discussed. We developed host-free transcriptomes of a myxozoan model organism from strains that exhibited different degrees of virulence, as a unique source of data that will foster functional gene analyses and serve as a base for the development of potential therapeutics for efficient control of these parasites.

scholarly journals Evaluating Coexistence of Fish Species with Coastal Cutthroat Trout in Low Order Streams of Western Oregon and Washington, USA

Fishes ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 4
Author(s):  
Kyle D. Martens ◽  
Jason Dunham
Keyword(s):  
Pacific Northwest ◽  
Species Interactions ◽  
Coho Salmon ◽  
Cutthroat Trout ◽  
Single Species ◽  
The Pacific ◽  
Small Streams ◽  
Coastal Cutthroat Trout ◽  
Multiple Species ◽  
Low Order

When multiple species of fish coexist there are a host of potential ways through which they may interact, yet there is often a strong focus on studies of single species without considering these interactions. For example, many studies of forestry–stream interactions in the Pacific Northwest have focused solely on the most prevalent species: Coastal cutthroat trout. To examine the potential for interactions of other fishes with coastal cutthroat trout, we conducted an analysis of 281 sites in low order streams located on Washington’s Olympic Peninsula and along the central Oregon coast. Coastal cutthroat trout and juvenile coho salmon were the most commonly found salmonid species within these streams and exhibited positive associations with each other for both presence and density. Steelhead were negatively associated with the presence of coastal cutthroat trout as well as with coho salmon and sculpins (Cottidae). Coastal cutthroat trout most frequently shared streams with juvenile coho salmon. For densities of these co-occurring species, associations between these two species were relatively weak compared to the strong influences of physical stream conditions (size and gradient), suggesting that physical conditions may have more of an influence on density than species interactions. Collectively, our analysis, along with a review of findings from prior field and laboratory studies, suggests that the net effect of interactions between coastal cutthroat trout and coho salmon do not appear to inhibit their presence or densities in small streams along the Pacific Northwest.

scholarly journals Can the creation of new freshwater habitat demographically offset losses of Pacific salmon from chronic anthropogenic mortality?

2020 ◽  
Author(s):  
Pascale Gibeau ◽  
Michael J. Bradford ◽  
Wendy J. Palen
Keyword(s):  
Pacific Northwest ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Life Stages ◽  
Typical Size ◽  
Side Channels ◽  
Lower Productivity ◽  
Freshwater Habitats ◽  
The Creation ◽  
Habitat Compensation

AbstractOver 1 billion USD are devoted annually to rehabilitating freshwater habitats to improve survival for the recovery of endangered salmon populations. Mitigation often requires the creation of new habitat (e.g. habitat compensation) to offset population losses from human activities, however compensation schemes are rarely evaluated. Anadromous Pacific salmon are ecologically, culturally, and economically important in the US and Canada, and face numerous threats from climate change, over-harvesting, and degradation of freshwater habitats. Here we used a matrix population model of coho salmon (Oncorhynchus kisutch) to determine the amount of habitat compensation needed to offset mortality (2-20% per year) caused by a range of development activities. We simulated chronic mortality to three different life stages (egg, parr, smolt/adult), individually and in combination, to mimic impacts from development, and evaluated if the number of smolts produced from constructed side-channels demographically offset losses. We show that under ideal conditions, the typical size of a constructed side-channel in the Pacific Northwest (PNW) (3405 m2) is sufficient to compensate for only relatively low levels of chronic mortality to either the parr or smolt/adult stages (2-7% per year), but populations do not recover if mortality is >10% per year. When we assumed lower productivity (e.g.; 25th percentile), or imposed mortality at multiple life stages, we found that constructed channels would need to be larger (0.2-4.5 times) than if we assumed mean productivity or as compared to the typical size built in the PNW, respectively, to maintain population sizes.. We conclude that habitat compensation has the potential to mitigate chronic mortality to early life stages, but that current practices are likely not sufficient when we incorporate more realistic assumptions about productivity of constructed side-channels and cumulative effects of anthropogenic disturbances on multiple life stages.

scholarly journals The Theory and Applications of Measuring Broad-Range and Chromosome-Wide Recombination Rate from Allele Frequency Decay around a Selected Locus

2020 ◽  
Vol 37 (12) ◽  
pp. 3654-3671
Author(s):  
Kevin H -C Wei ◽  
Aditya Mantha ◽  
Doris Bachtrog
Keyword(s):  
Genetic Distance ◽  
Allele Frequency ◽  
Recombination Rate ◽  
High Throughput Sequencing ◽  
Genetic Material ◽  
Cost Effective ◽  
Genetic Distances ◽  
Recombination Rates ◽  
Marker Selection ◽  
Cost Effective Approach

Abstract Recombination is the exchange of genetic material between homologous chromosomes via physical crossovers. High-throughput sequencing approaches detect crossovers genome wide to produce recombination rate maps but are difficult to scale as they require large numbers of recombinants individually sequenced. We present a simple and scalable pooled-sequencing approach to experimentally infer near chromosome-wide recombination rates by taking advantage of non-Mendelian allele frequency generated from a fitness differential at a locus under selection. As more crossovers decouple the selected locus from distal loci, the distorted allele frequency attenuates distally toward Mendelian and can be used to estimate the genetic distance. Here, we use marker selection to generate distorted allele frequency and theoretically derive the mathematical relationships between allele frequency attenuation, genetic distance, and recombination rate in marker-selected pools. We implemented nonlinear curve-fitting methods that robustly estimate the allele frequency decay from batch sequencing of pooled individuals and derive chromosome-wide genetic distance and recombination rates. Empirically, we show that marker-selected pools closely recapitulate genetic distances inferred from scoring recombinants. Using this method, we generated novel recombination rate maps of three wild-derived strains of Drosophila melanogaster, which strongly correlate with previous measurements. Moreover, we show that this approach can be extended to estimate chromosome-wide crossover interference with reciprocal marker selection and discuss how it can be applied in the absence of visible markers. Altogether, we find that our method is a simple and cost-effective approach to generate chromosome-wide recombination rate maps requiring only one or two libraries.

The chicken model organism for epigenomic research

Genome ◽  
2020 ◽  
Author(s):  
Tasnim H. BEACON ◽  
James R DAVIE
Keyword(s):  
High Throughput Sequencing ◽  
Chicken Genome ◽  
Regulation Of Gene Expression ◽  
Model Organism ◽  
Bioinformatic Tools ◽  
Sequencing Technologies ◽  
Trace Back ◽  
Human Orthologs ◽  
Genomic Studies ◽  
Chicken Model

The chicken model organism has advanced the areas of developmental biology, virology, immunology, oncology, epigenetic regulation of gene expression, conservation biology, and genomics of domestication. Further, the chicken model organism has aided in our understanding of human disease. Through the recent advances in high-throughput sequencing and bioinformatic tools, researchers have successfully identified sequences in the chicken genome that have human orthologs, improving mammalian genome annotation. In this review, we highlight the importance of chicken as an animal model in basic and pre-clinical research. We will present the importance of chicken in poultry epigenetics and in genomic studies that trace back to their ancestor, the last link between human and chicken tree of life. There are still many genes of unknown function in the chicken genome yet to be characterized. By taking advantage of recent sequencing technologies, it is possible to gain further insight into the chicken epigenome.

scholarly journals A Comprehensive Coexpression Network Analysis in Vibrio cholerae

mSystems ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Cory D. DuPai ◽  
Claus O. Wilke ◽  
Bryan W. Davies
Keyword(s):  
Network Analysis ◽  
Vibrio Cholerae ◽  
Rna Sequencing ◽  
High Throughput Sequencing ◽  
Model Organism ◽  
Coexpression Network ◽  
Sequencing Data ◽  
Content Type ◽  
The Impact ◽  
Coexpression Network Analysis

ABSTRACT Research into the evolution and pathogenesis of Vibrio cholerae has benefited greatly from the generation of high-throughput sequencing data to drive molecular analyses. The steady accumulation of these data sets now provides a unique opportunity for in silico hypothesis generation via coexpression analysis. Here, we leverage all published V. cholerae RNA sequencing data, in combination with select data from other platforms, to generate a gene coexpression network that validates known gene interactions and identifies novel genetic partners across the entire V. cholerae genome. This network provides direct insights into genes influencing pathogenicity, metabolism, and transcriptional regulation, further clarifies results from previous sequencing experiments in V. cholerae (e.g., transposon insertion sequencing [Tn-seq] and chromatin immunoprecipitation sequencing [ChIP-seq]), and expands upon microarray-based findings in related Gram-negative bacteria. IMPORTANCE Cholera is a devastating illness that kills tens of thousands of people annually. Vibrio cholerae, the causative agent of cholera, is an important model organism to investigate both bacterial pathogenesis and the impact of horizontal gene transfer on the emergence and dissemination of new virulent strains. Despite the importance of this pathogen, roughly one-third of V. cholerae genes are functionally unannotated, leaving large gaps in our understanding of this microbe. Through coexpression network analysis of existing RNA sequencing data, this work develops an approach to uncover novel gene-gene relationships and contextualize genes with no known function, which will advance our understanding of V. cholerae virulence and evolution.

Environmental factors influencing freshwater survival and smolt production in Pacific Northwest coho salmon (Oncorhynchus kisutch)

2004 ◽  
Vol 61 (3) ◽  
pp. 360-373 ◽  
Author(s):  
P W Lawson ◽  
E A Logerwell ◽  
N J Mantua ◽  
R C Francis ◽  
V N Agostini
Keyword(s):  
Pacific Northwest ◽  
Air Temperature ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Stream Flows ◽  
Factors Influencing ◽  
Life Phase ◽  
Air Temperatures ◽  
Queets River ◽  
Marine Survival

Climate variability is well known to affect the marine survival of coho salmon (Oncorhynchus kisutch) in Oregon and Washington. Marine factors have been used to explain up to 83% of the variability in Oregon coastal natural coho salmon recruitment, yet about half the variability in coho salmon recruitment comes from the freshwater life phase of the life cycle. This seeming paradox could be resolved if freshwater variability were linked to climate and climate factors influencing marine survival were correlated with those affecting freshwater survival. Effects of climate on broad-scale fluctuations in freshwater survival or production are not well known. We examined the influence of seasonal stream flows and air temperature on freshwater survival and production of two stock units: Oregon coastal natural coho salmon and Queets River coho salmon from the Washington Coast. Annual air temperatures and second winter flows correlated strongly with smolt production from both stock units. Additional correlates for the Oregon Coast stocks were the date of first fall freshets and flow during smolt outmigration. Air temperature is correlated with sea surface temperature and timing of the spring transition so that good freshwater conditions are typically associated with good marine conditions.

scholarly journals Phylogenetic relationships of endornaviruses in common bean from the western highlands of Kenya and global sequences

2018 ◽  
Author(s):  
James M Wainaina ◽  
Elijah Ateka ◽  
Timothy Makori ◽  
Monica A Kehoe ◽  
Laura M Boykin
Keyword(s):  
Phaseolus Vulgaris ◽  
Complete Genome ◽  
High Throughput Sequencing ◽  
De Novo ◽  
Current Knowledge ◽  
Sequence Similarity ◽  
Evolutionary Relationship ◽  
Sub Saharan Africa ◽  
Complete Genomes ◽  
Sub Saharan

Background: Endornaviruses are non-pathogenic viruses infecting multiple agricultural important crops including legumes, with global distribution. However, there is an absence on the complete genome of endornaviruses from legumes in particular with the sub-Saharan region. In this study, we report the first complete genomes of PvEV1 and PvEV2, and the evolutionary relationship of these genomes. Methods: Viral symptomatic common beans (Phaseolus vulgaris) showing Bean common mosaic necrosis virus (BCMNV) symptoms from Vihiga county, in the western highlands of Kenya were collected during field survey’s in the region. High throughput sequencing (RNA-Seq) was carried out on total RNA isolated from symptomatic leaf samples. Subsequently, de novo assembly and reference mapping was carried out to obtain the complete genomes of PvEV-1 and PvEV-2. Results: We identified the complete genome of Phaseolus vulgaris endornavirus 1 and 2 (PvEV-1 and PvEV-2) from sub-Saharan Africa (SSA). The average genome size of PvEV-1 was ~13,890 nucleotides (nt) while PvEV-2 was ~14,698 nt, encoding a single open reading frame (ORF). Single ORFs ranged from 4,632 to 4,633 aa in PvEV-1 and from 4,899 – to 4,954 aa in PvEV-2. Both ORFs encoded for the RNA-dependent RNA polymerase (RdRP) gene. The percentage sequence similarity between PvEV-1, PvEV-2 from this study GenBanks sequences was 29 % to 99 %. Bayesian phylogenetic analysis resolved in two well-supported monophyletic clades, with isolates from this study clustering with those from Brazil sequences. Discussion: This study provides the first insights into the evolutionary relationships of PvEV from SSA diverse and contributes towards filling the current knowledge gaps on endornaviruses

scholarly journals Phylogenetic relationships of endornaviruses in common bean from the western highlands of Kenya and global sequences

2018 ◽  
Author(s):  
James M Wainaina ◽  
Elijah Ateka ◽  
Timothy Makori ◽  
Monica A Kehoe ◽  
Laura M Boykin
Keyword(s):  
Phaseolus Vulgaris ◽  
Complete Genome ◽  
High Throughput Sequencing ◽  
De Novo ◽  
Current Knowledge ◽  
Sequence Similarity ◽  
Evolutionary Relationship ◽  
Sub Saharan Africa ◽  
Complete Genomes ◽  
Sub Saharan

Background: Endornaviruses are non-pathogenic viruses infecting multiple agricultural important crops including legumes, with global distribution. However, there is an absence on the complete genome of endornaviruses from legumes in particular with the sub-Saharan region. In this study, we report the first complete genomes of PvEV1 and PvEV2, and the evolutionary relationship of these genomes. Methods: Viral symptomatic common beans (Phaseolus vulgaris) showing Bean common mosaic necrosis virus (BCMNV) symptoms from Vihiga county, in the western highlands of Kenya were collected during field survey’s in the region. High throughput sequencing (RNA-Seq) was carried out on total RNA isolated from symptomatic leaf samples. Subsequently, de novo assembly and reference mapping was carried out to obtain the complete genomes of PvEV-1 and PvEV-2. Results: We identified the complete genome of Phaseolus vulgaris endornavirus 1 and 2 (PvEV-1 and PvEV-2) from sub-Saharan Africa (SSA). The average genome size of PvEV-1 was ~13,890 nucleotides (nt) while PvEV-2 was ~14,698 nt, encoding a single open reading frame (ORF). Single ORFs ranged from 4,632 to 4,633 aa in PvEV-1 and from 4,899 – to 4,954 aa in PvEV-2. Both ORFs encoded for the RNA-dependent RNA polymerase (RdRP) gene. The percentage sequence similarity between PvEV-1, PvEV-2 from this study GenBanks sequences was 29 % to 99 %. Bayesian phylogenetic analysis resolved in two well-supported monophyletic clades, with isolates from this study clustering with those from Brazil sequences. Discussion: This study provides the first insights into the evolutionary relationships of PvEV from SSA diverse and contributes towards filling the current knowledge gaps on endornaviruses

scholarly journals The bacterial community structure dynamics in Meloidogyne incognita infected roots and its role in worm-microbiome interactions

2020 ◽  
Author(s):  
Timur Yergaliyev ◽  
Rivka Alexander-Shani ◽  
Hanna Dimeretz ◽  
Shimon Pivonia ◽  
David McK. Bird ◽  
...  
Keyword(s):  
High Resolution ◽  
Meloidogyne Incognita ◽  
High Throughput Sequencing ◽  
Low Cost ◽  
Model Organism ◽  
Complex Life Cycle ◽  
Parasitic Nematodes ◽  
Second Stage ◽  
Root Segments ◽  
Low Genetic Diversity

AbstractBackgroundPlant parasitic nematodes such as Meloidogyne incognita have a complex life cycle, occurring sequentially in various niches of the root and rhizosphere. They are known to form a range of interactions with bacteria and other microorganisms, that can affect their densities and virulence. High throughput sequencing can reveal these interactions in high temporal, and geographic resolutions, although thus far we have only scratched the surface. We have carried out a longitudinal sampling scheme, repeatedly collecting rhizosphere soil, roots, galls and second stage juveniles from 20 plants to provide a high resolution view of bacterial succession in these niches, using 16S rRNA metabarcoding.ResultsWe find that a structured community develops in the root, in which gall communities diverge from root segments lacking a gall, and that this structure is maintained throughout the crop season. We detail the successional process leading toward this structure, which is driven by interactions with the nematode and later by an increase in bacteria often found in hypoxic and anaerobic environments. We show evidence that this structure may play a role in the nematode’s chemotaxis towards uninfected root segments. Finally, we describe the J2 epibiotic microenvironment as ecologically deterministic, in part, due to active bacterial attraction of second stage juveniles.ConclusionsHigh density sampling, both temporally and across adjacent microniches, coupled with the power and relative low cost of metabarcoding, has provided us with a high resolution description of our study system. Such an approach can advance our understanding of holobiont ecology. Meloidogyne spp., with their relatively low genetic diversity, large geographic range and the simplified agricultural ecosystems they occupy, can serve as a model organism. Additionally, the perspective this approach provides could promote the efforts toward biological control efficacy.

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