Constitutive and inducible nonphotochemical quenching (NPQ) underpin survival of Chlamydomonas sp. ICE-MDV within its native habitat (Lake Bonney, Antarctica)
Year: 2025
Type: preprint
Abstract: Photosynthetic organisms possess diverse strategies to maintain photosynthetic efficiency under environmental stress across vast timescales. In the McMurdo Dry Valleys (MDVs), Antarctica, phytoplankton perform photosynthesis under permanent environmental extremes. The MDV water columns are chemically stratified, creating a vertical gradient in which algal populations experience severe nutrient deprivation in surface waters and hypersalinity at the bottom of the photic zone. How MDV phytoplankton maintain efficient photobiology while avoiding photooxidative damage under prolonged stress and spatially variable conditions remains poorly understood. We deployed dialysis chambers to assess the physiological responses of a model MDV algal isolate, Chlamydomonas sp. ICE-MDV, across the stratified photic zone of the MDV Lake Bonney. C. sp. ICE-MDV showed robust ability to photoacclimate across the stratified photic zone. Nonphotochemical quenching (NPQ) was sensitive to light intensity, while NPQ capacity responded to salinity. Elevated NPQ was associated with the activation of photosystem I (PSI)-linked cyclic electron flow. NPQ and light were associated with expression of the light stress gene, LHCSR2 , while expression other cellular stress genes were associated with salinity stress. These findings suggest that the ability to modulate photochemical efficiency and cellular stress responses are crucial adaptations that enable chlorophytes to thrive in Antarctic lakes.
Authors: Wei Li, Sedlacek C.J., Teufel A., Krzysiak B., Kalra, Powell T., Hahn M.M., Popson D., Rachael Morgan-Kiss
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: gold
OpenAlex ID: W4413434943