Cristin-prosjekt-ID: 2512209
Sist endret: 15. juni 2021, 14:09

Cristin-prosjekt-ID: 2512209
Sist endret: 15. juni 2021, 14:09
Prosjekt

ViralICE: Viral diversity and Interactions in a Changing Environment on Kelp.

prosjektleder

Ingunn Alne Hoell
ved Institutt for sikkerhet, kjemi- og bioingeniørfag ved Høgskulen på Vestlandet

prosjekteier / koordinerende forskningsansvarlig enhet

  • Høgskulen på Vestlandet

Finansiering

  • TotalbudsjettNOK 8.700.000
  • Norges forskningsråd
    Prosjektkode: 314108

Klassifisering

Vitenskapsdisipliner

Marinbiologi • Økologi • Akvakultur • Molekylærbiologi

Emneord

Akvakultur • Makroalger • Akvatisk miljø • Marine økosystemfunkjoner • Molekylær virologi • Marin mikrobiologi • Virologi

Kategorier

Prosjektkategori

  • Grunnforskning

Kontaktinformasjon

Telefon
94241858
Sted
Eliana Ruiz Martínez

Tidsramme

Aktivt
Start: 1. mars 2021 Slutt: 1. mars 2024

Beskrivelse Beskrivelse

Tittel

ViralICE: Viral diversity and Interactions in a Changing Environment on Kelp.

Populærvitenskapelig sammendrag

Kelps are brown algae from the order Laminariales that predominate along rocky coastal areas with cold and relatively shallow waters around the world. Like other marine photosynthetic organisms, kelps fuel secondary production via macroalgal detritus; thereby supporting complex food webs in coastal zones. Since they grow in dense groupings, like underwater forests, they also provide physical habitat, nursery ground and food for organisms, such as marine mammals, fishes, crabs, sea urchins, molluscs, other algae and epibiota. Kelp forest is capable of altering local oceanography and ecology by dampening wave surge, which influence water flow, coastal erosion, sedimentation, benthic productivity (primary and secondary) and recruitment. It can also influence interspecific competition among algae, since their canopy shades the seafloor, allowing low-light intensity species to grow. Kelp is not just a key species for the marine environment, but also for us. Their multiple industrial applications have led to an increase in the economic importance of seaweed aquaculture.

 

 

However, 38% of the world’s kelp forests have been in decline over the past five decades possibly due to coastal eutrophication and rising sea temperatures, among others. Norwegian Kelp populations have been fluctuating without an obvious reason and, the recent discovery of Phaeoviruses infecting Kelp species opens a new door for studying viral infection as a possible vector for this regime shift. Domesticated seaweed are more susceptible to abiotic stressors, disease and parasites. If they are a reservoir for disease, besides the economic burden, they can impact natural populations. ViralICE project therefore aims to find out whether and how kelp viruses affect the natural kelp forest in Norway (structure and functioning) and kelp aquaculture (management of marine coastal resources) under the current climate change situation. And make it viral!

Vitenskapelig sammendrag

Being the most abundant and diverse entities in planet Earth, marine viruses have been proved to control their host populations, acting as driving force for the inter- and intra-species competition and succession. Their outstanding roles in food webs, competitive interactions, biodiversity patterns, and the regulation of keystone species, manifest therefore, their contribution structuring ecological communities and impacting ecosystem functioning. However, we still do not completely understand how viruses interact with their hosts.

 

Kelp forest (brown algae from the order Laminariales) impacts local oceanography and ecology, and constitute enormous energy sources for coastal benthic secondary production supporting fisheries worldwide; from temperate, to polar rocky ecosystems. Kelp deforestation has been reported globally and, after the recent discovery of Phaeoviruses on kelp, viral diseases should be taken into consideration. Evidence posses that host-pathogen interactions will become more frequent and intense in the future, leading to higher virus multiplication rates, increased transmission and host species jumps. Wild seaweed domestication is making crops more susceptible to abiotic stressors, disease and parasites, and these may act as a disease reservoir which could impact natural populations. Therefore, viral infection could not only affect natural kelp forest, but also impact the Norwegian blue bioeconomy.

 

ViralICE has been designed to throw some light into viral diseases that could potentially affect kelp communities and relevant species to the Norwegian industry. This project intends to contribute with Phaeoviral infection knowledge in brown algae, and we will: 1) study Phaeoviral diversity, 2) study the Phaeoviral host-range, 3) study the potential ecological consequences of climate change on algal-pathogen interactions, and 4) build relevant networks between research communities, industry and government.

 

Metode

The project is divided in 2 working packages (WP):

  • WP1: Phaeoviral diversity and phylogeny on relevant kelp species:

We will work with natural and cultured samples provided by UIB and our industry collaborators, Ocean Forest and DuPont Health & Nutrition.  

All samples will be screened for viral detection through DNA extraction following Maeda et al. 2013 and Mckeown et al. 2018, and targeting the phaeovirus-encoded major capsid protein (MCP). PCRs, Real-Time PCR (qPCR) and High Resolution Melt (HRM) analysis will be performed following to McKeown and colleagues. The raw melting temperatures will be calibrated by applying the correction factor from reference clones and genomic DNA. Each corrected melting temperature will be assigned to a viral subgroup using posterior group probabilities. All PCR products will be sequenced by Sanger sequencing.

Different parts from the samples will be analysed, meaning reproductive (sporophytes and gametophytes) and vegetative tissue.. This will enable us to test the hypothesis that phaeoviruses on kelp are expressed in gametophytes and vegetative cells, in contrast to in ectocarpoids, where viral expression occurs in both reproductive structures, but not in vegetative cells. Note that gametophyte cultures will be obtained from sporophyte spore release in the laboratory (methodology described under WP2). DAPI staining, along with light and epifluorescence microscopy, will be used to support the results obtained by molecular techniques, and further characterize the nature of viral infections on these species in cases a new viral line has been found.

For the phylogeny study, we will work with the obtained phaeoviral positive samples. BLAST research will be performed to investigate the homology between our MCP sequences and the so far described sequences in the GenBank database.

Distance analysis will be performed using the software MEGA7, bayesian inference analysis will be performed using MrBayes v3.2, and trees will be visualized using Inkscape 0.92 and Dendroscope 3. Host-virus infection analysis will be performed using the BiMat package for Matlab. 

Virus-host Phylogenetic affiliation of the phaeoviruses in our samples, along with the infection network analysis will tell us if these are similar or different from the described cultured or uncultured phaeoviruses, potentially providing general information about their evolutionary history and life strategies.

  • WP2: Potential ecological consequences of climate change on algal-pathogen interactions.

During the first year of sampling, diverse physicochemical parameters of the water will be measured (e.g. temperature, salinity and hydrodynamics) at the same time the samples are collected. Correlations between these variables and the presence of viruses in the samples from all locations will be done in order to determinate if temperature gradients, in this case, increase or decrease viral presence.

Experimental tests will be also done with reproductive kelp, previously scanned for viruses.

 

In order to integrate WP1 and WP2, statistical analyses will be performed in the R statistical computing environment using different community ecology and graphic packages such as vegan v2.4.5, ggplot2 v3.0.0, and gplots v3.0.1. In this way, we will look after significance of our data and possible variable correlations (using ordination methods like PCA analysis), to properly explain and interpret our results.

Utstyr

  • WP1: Phaeoviral diversity and phylogeny on relevant kelp species:

Ocean Forest AS will provide S. latissima cultivated in Austevoll  (Hordaland) and DuPont Health & Nutrition L. hyperborea harvested in two different locations (Rogaland and Sør Trøndelag), in order to correlate viral presence with climatic parameters in the natural environment (WP2).

30-40 sporophytes/sampling location will be sampled four times during the first year, once per season. Epiphyte-free, clean meristematic tissue will be cut from kelp sporophytes (diploid) and stored in silica gel. 10–20 mg dry weight of sporophyte material will be frozen in liquid nitrogen and homogenized with pestle and mortar. UIB has already frozen DNA samples from kelp sporophytes from around 20 stations along the Norwegian coast, kept from a previous microsatellite study. The locations of these stations range from enclosed fjord areas to open coastal areas, and are characterised by different temperatures and salinities.

  • WP2: Potential ecological consequences of climate change on algal-pathogen interactions.

After spore release the gametophyte survival and growth will be compared between infected ones versus non-infected individuals, for each species. Lamina carrying sporangia (sori) will be cut away from the central lamina, previously blotted dry with paper towels. 27 mm diameter discs of tissue will be punched from each central lamina with a PVC corer, starting at the distal end of the thallus, until achieving a total amount of 100 g. Meiospore induction from the discs will be carried out according to Mohring and colleagues, using 18×18 mm coverslips and 50 mm diameter Petri dishes with 20 ml Provasoli-Enriched seawater (PES) and GeO2 solution will be added to prevent diatom growth. Provasoli solution contains increased levels of nitrate and phosphate, a TRIS base buffer, trace metals and vitamins meaning that the seawater for algae culture is not nutrient limiting. This will also ensure any temporal changes in growth and survival would not be confounded by seasonal shifts in water quality. After the 18h settlement period, 2 slides will be randomly selected and placed at the bottom of each Petri dish; having 20 Petri dishes per treatment – infected versus healthy (control)- and a total number of 40 per kelp species, therefore a total number of 80 for both species. Samples will be cultured under different temperatures: 10, 15, 20, 22°C (with 5 sub-replicates per temperature value). These treatments were selected to encompass all temperatures that both kelp species are subjected to throughout their distribution in Norway and under future climate change previsions, and taking into account the optimal temperature for vegetative growth of gametophytes in north Atlantic cold-temperate species; which ranges between 10 and 17°. All samples will be cultured using blue light (400-512nm) and with quantum doses of 50 to 870 μmol cm-2; photoperiod 12 h light∶12 h dark. One coverslip will be harvested at days 1, 3 and 6. Slides will be examined under a compound microscope and six random photographs (0.17×0.13 mm) will be taken from each slide. Gametophyte densities will be collected from each photo, and the area of one individual per photo will be measured using ImageJ software. Effects on survival and growth will be inferred from differences in relative density and size after six days.

prosjektdeltakere

prosjektleder

Ingunn Alne Hoell

  • Tilknyttet:
    Prosjektleder
    ved Institutt for sikkerhet, kjemi- og bioingeniørfag ved Høgskulen på Vestlandet

Declan C. Schroeder

  • Tilknyttet:
    Prosjektdeltaker
    ved University of Minnesota

Aud Larsen

  • Tilknyttet:
    Prosjektdeltaker
    ved NORCE Miljø ved NORCE Norwegian Research Centre AS

Inga Kjersti Sjøtun

  • Tilknyttet:
    Prosjektdeltaker
    ved Institutt for biovitenskap ved Universitetet i Bergen

Ruth-Anne Sandaa

  • Tilknyttet:
    Prosjektdeltaker
    ved Institutt for biovitenskap ved Universitetet i Bergen
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