Photoacclimation strategies of Chlamydomonas reinhardtii in response to high-light stress in stationary phase
Loading...
Date
2024-09
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of New Brunswick
Abstract
Chlamydomonas reinhardtii can photoacclimate to excess light through short- and long-term mechanisms. During prolonged light stress, cell growth and division help reduce photosynthetic protein concentrations, establishing a new photosynthetic baseline. As nutrients deplete, division rate declines but persists during the declining growth phase (DGP), partially aiding photoacclimation through dilution and quenching mechanisms. This study explored C. reinhardtii’s protection from high-light stress during its stationary phase when cell division is limited. We monitored wildtype strain (CC125) over five days in stationary phase under low-light (LL) and high-light (HL) conditions. Both showed chlorophyll decline, signifying senescence, with HL cells declining faster. HL-exposed cells resumed growth after two days, likely due to metabolite availability from photosynthetic complex turnover. We also found that the npq4 mutant (CC4614), lacking LHCSR3, survived HL without significant NPQ induction, suggesting alternative survival mechanisms. These findings demonstrate how C. reinhardtii manages high light during stationary phases to maximize longevity.