Cold-induced [Ca2+]cyt elevations function to support osmoregulation in marine diatoms

Kleiner, Friedrich H., Helliwell, Katherine E., Chrachri, Abdul, Hopes, Amanda, Parry-Wilson, Hannah, Gaikwad, Trupti, Mieszkowska, Nova, Mock, Thomas ORCID:, Wheeler, Glen L. and Brownlee, Colin (2022) Cold-induced [Ca2+]cyt elevations function to support osmoregulation in marine diatoms. Plant Physiology, 190 (2). pp. 1384-1399. ISSN 0032-0889

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Diatoms are a group of microalgae that are important primary producers in a range of open ocean, freshwater, and intertidal environments. The latter can experience substantial long- and short-term variability in temperature, from seasonal variations to rapid temperature shifts caused by tidal immersion and emersion. As temperature is a major determinant in the distribution of diatom species, their temperature sensory and response mechanisms likely have important roles in their ecological success. We examined the mechanisms diatoms use to sense rapid changes in temperature, such as those experienced in the intertidal zone. We found that the diatoms Phaeodactylum tricornutum and Thalassiosira pseudonana exhibit a transient cytosolic Ca2+ ([Ca2+]cyt) elevation in response to rapid cooling, similar to those observed in plant and animal cells. However, [Ca2+]cyt elevations were not observed in response to rapid warming. The kinetics and magnitude of cold-induced [Ca2+]cyt elevations corresponded with the rate of temperature decrease. We did not find a role for the [Ca2+]cyt elevations in enhancing cold tolerance but showed that cold shock induces a Ca2+-dependent K+ efflux and reduces mortality of P. tricornutum during a simultaneous hypo-osmotic shock. As intertidal diatom species may routinely encounter simultaneous cold and hypo-osmotic shocks during tidal cycles, we propose that cold-induced Ca2+ signaling interacts with osmotic signaling pathways to aid in the regulation of cell volume. Our findings provide insight into the nature of temperature perception in diatoms and highlight that cross-talk between signaling pathways may play an important role in their cellular responses to multiple simultaneous stressors.

Item Type: Article
Additional Information: Funding: The work was supported by a European Research Council Advanced Grant to CB (ERC‐ADG‐670390) and a Natural Environment Research Council award to GLW (NE/V013343/1).
Uncontrolled Keywords: sdg 14 - life below water ,/dk/atira/pure/sustainabledevelopmentgoals/life_below_water
Faculty \ School: Faculty of Science > School of Environmental Sciences
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Depositing User: LivePure Connector
Date Deposited: 20 Oct 2022 14:30
Last Modified: 24 Oct 2022 06:54
DOI: 10.1093/plphys/kiac324

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