Publication Date:
2019-07-16
Description:
Ocean acidification is considered a major threat to marine ecosystems and may particularly
affect primary producers. Here we investigated the impact of elevated pCO2 on paralytic
shellfish poisoning toxin (PST) content and composition in two strains of Alexandrium
tamarense, Alex5 and Alex2. Experiments were carried out as dilute batch to keep carbonate
chemistry unaltered over time. We observed only minor changes with respect to
growth and elemental composition in response to elevated pCO2. For both strains, the
cellular PST content, and in particular the associated cellular toxicity, was lower in the high
CO2 treatments. In addition, Alex5 showed a shift in its PST composition from a nonsulfated
analogue towards less toxic sulfated analogues with increasing pCO2. Transcriptomic
analyses suggest that the ability of A. tamarense to maintain cellular homeostasis
is predominantly regulated on the post-translational level rather than on the
transcriptomic level. Furthermore, genes associated to secondary metabolite and amino
acid metabolism in Alex5 were down-regulated in the high CO2 treatment, which may
explain the lower PST content. Elevated pCO2 also induced up-regulation of a putative
sulfotransferase sxtN homologue and a substantial down-regulation of several sulfatases.
Such changes in sulfur metabolism may explain the shift in PST composition towards more
sulfated analogues. All in all, our results indicate that elevated pCO2 will have minor
consequences for growth and elemental composition, but may potentially reduce the
cellular toxicity of A. tamarense.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf
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