Cold-induced [Ca2+]cyt elevations function to support osmoregulation in marine diatoms
Friedrich H Kleiner1,2, Katherine E Helliwell1,3, Abdul Chrachri1
1The Marine Biological Association of the United Kingdom, The Laboratory, Plymouth PL1 2PB, UK.
Plant Physiology
|July 27, 2022
Summary
Diatoms sense rapid cooling via cytosolic calcium ([Ca2+]cyt) increases, not warming. This calcium signaling aids survival during simultaneous cold and osmotic stress in intertidal zones.
Area of Science:
- Marine biology
- Microalgal physiology
- Environmental sensing
Background:
- Diatoms are crucial primary producers in diverse aquatic environments.
- Intertidal diatoms face significant temperature fluctuations due to tidal cycles.
- Understanding diatom temperature response mechanisms is key to their ecological success.
Purpose of the Study:
- Investigate how diatoms perceive and respond to rapid temperature changes.
- Elucidate the role of calcium signaling in diatom temperature perception.
- Determine the functional significance of cold-induced signaling in intertidal diatoms.
Main Methods:
- Utilized Phaeodactylum tricornutum and Thalassiosira pseudonana for experiments.
- Measured cytosolic calcium ([Ca2+]cyt) levels in response to thermal shocks.
- Assessed potassium (K+) efflux and mortality under combined cold and hypo-osmotic stress.
Main Results:
- Rapid cooling induced transient cytosolic calcium ([Ca2+]cyt) elevations in diatoms.
- No significant [Ca2+]cyt elevation was observed upon rapid warming.
- Cold shock triggered a calcium-dependent potassium efflux, reducing mortality during hypo-osmotic shock.
Conclusions:
- Diatoms possess a cold-sensing mechanism involving cytosolic calcium ([Ca2+]cyt) transients.
- Cold-induced calcium signaling is not directly linked to enhanced cold tolerance.
- Cross-talk between cold and osmotic signaling pathways likely regulates cell volume and survival in intertidal diatoms.
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