Publication Date:
2019-12-28
Description:
Background: Kelps (Laminariales, Phaeophyceae) are brown macroalgae of utmost ecological, and increasingly
economic, importance on temperate to polar rocky shores. Omics approaches in brown algae are still scarce and
knowledge of their acclimation mechanisms to the changing conditions experienced in coastal environments can
benefit from the application of RNA-sequencing.
Despite evidence of ecotypic differentiation, transcriptomic responses from distinct geographical locations have, to
our knowledge, never been studied in the sugar kelp Saccharina latissima so far.
Results: In this study we investigated gene expression responses using RNA-sequencing of S. latissima from
environments with contrasting temperature and salinity conditions – Roscoff, in temperate eastern Atlantic, and
Spitsbergen in the Arctic. Juvenile sporophytes derived from uniparental stock cultures from both locations were
pre-cultivated at 8 °C and SA 30. Sporophytes acclimated to 0 °C, 8 °C and 15 °C were exposed to a low salinity
treatment (SA 20) for 24 h. Hyposalinity had a greater impact at the transcriptomic level than the temperature alone,
and its effects were modulated by temperature. Namely, photosynthesis and pigment synthesis were extensively
repressed by low salinity at low temperatures. Although some responses were shared among sporophytes from the
different sites, marked differences were revealed by principal component analysis, differential expression and GO
enrichment. The interaction between low temperature and low salinity drove the largest changes in gene
expression in sporophytes from Roscoff while specimens from Spitsbergen required more metabolic adjustment at
higher temperatures. Moreover, genes related to cell wall adjustment were differentially expressed between
Spitsbergen and Roscoff control samples.
Conclusions: Our study reveals interactive effects of temperature and salinity on transcriptomic profiles in S.
latissima. Moreover, our data suggest that under identical culture conditions sporophytes from different locations
diverge in their transcriptomic responses. This is probably connected to variations in temperature and salinity in
their respective environment of origin. The current transcriptomic results support the plastic response pattern in
sugar kelp which is a species with several reported ecotypes. Our data provide the baseline for a better
understanding of the underlying processes of physiological plasticity and may help in the future to identify strains
adapted to specific environments and its genetic control.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf
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