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Hüner NPA, Smith DR, Cvetkovska M, Zhang X, Ivanov AG, Szyszka-Mroz B, Kalra I, Morgan-Kiss R. Photosynthetic adaptation to polar life: Energy balance, photoprotection and genetic redundancy. JOURNAL OF PLANT PHYSIOLOGY 2022; 268:153557. [PMID: 34922115 DOI: 10.1016/j.jplph.2021.153557] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 09/27/2021] [Accepted: 10/24/2021] [Indexed: 06/14/2023]
Abstract
The persistent low temperature that characterize polar habitats combined with the requirement for light for all photoautotrophs creates a conundrum. The absorption of too much light at low temperature can cause an energy imbalance that decreases photosynthetic performance that has a negative impact on growth and can affect long-term survival. The goal of this review is to survey the mechanism(s) by which polar photoautotrophs maintain cellular energy balance, that is, photostasis to overcome the potential for cellular energy imbalance in their low temperature environments. Photopsychrophiles are photosynthetic organisms that are obligately adapted to low temperature (0⁰- 15 °C) but usually die at higher temperatures (≥20 °C). In contrast, photopsychrotolerant species can usually tolerate and survive a broad range of temperatures (5⁰- 40 °C). First, we summarize the basic concepts of excess excitation energy, energy balance, photoprotection and photostasis and their importance to survival in polar habitats. Second, we compare the photoprotective mechanisms that underlie photostasis and survival in aquatic cyanobacteria and green algae as well as terrestrial Antarctic and Arctic plants. We show that polar photopsychrophilic and photopsychrotolerant organisms attain energy balance at low temperature either through a regulated reduction in the efficiency of light absorption or through enhanced capacity to consume photosynthetic electrons by the induction of O2 as an alternative electron acceptor. Finally, we compare the published genomes of three photopsychrophilic and one photopsychrotolerant alga with five mesophilic green algae including the model green alga, Chlamydomonas reinhardtii. We relate our genomic analyses to photoprotective mechanisms that contribute to the potential attainment of photostasis. Finally, we discuss how the observed genomic redundancy in photopsychrophilic genomes may confer energy balance, photoprotection and resilience to their harsh polar environment. Primary production in aquatic, Antarctic and Arctic environments is dependent on diverse algal and cyanobacterial communities. Although mosses and lichens dominate the Antarctic terrestrial landscape, only two extant angiosperms exist in the Antarctic. The identification of a single 'molecular key' to unravel adaptation of photopsychrophily and photopsychrotolerance remains elusive. Since these photoautotrophs represent excellent biomarkers to assess the impact of global warming on polar ecosystems, increased study of these polar photoautotrophs remains essential.
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Affiliation(s)
- Norman P A Hüner
- Dept. of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, N6A 5B7, Canada.
| | - David R Smith
- Dept. of Biology, University of Western Ontario, London, N6A 5B7, Canada.
| | | | - Xi Zhang
- Dept. of Biology, University of Western Ontario, London, N6A 5B7, Canada.
| | - Alexander G Ivanov
- Dept. of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, N6A 5B7, Canada; Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, 1113, Bulgaria.
| | - Beth Szyszka-Mroz
- Dept. of Biology and the Biotron Centre for Experimental Climate Change Research, University of Western Ontario, London, N6A 5B7, Canada.
| | - Isha Kalra
- Dept. of Microbiology, Miami University of Ohio, Oxford, OH, 45056, USA.
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Takizawa K, Takahashi S, Hüner NPA, Minagawa J. Salinity affects the photoacclimation of Chlamydomonas raudensis Ettl UWO241. PHOTOSYNTHESIS RESEARCH 2009; 99:195-203. [PMID: 19137412 DOI: 10.1007/s11120-008-9397-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 12/23/2008] [Indexed: 05/09/2023]
Abstract
Chlamydomonas raudensis Ettl UWO241, a natural variant of C. raudensis, is deficient in state transitions. Its habitat, the deepest layer of Lake Bonney in Antarctica, features low irradiance, low temperature, and high salinity. Although psychrophily and low-light acclimation of this green alga has been described, very little information is available on the effect of salinity. Here, we demonstrate that this psychrophile is halotolerant, not halophilic, and it shows energy redistribution between photosystem I and II based on energy spillover under low-salt conditions. Furthermore, we revealed that C. raudensis exhibits higher non-photochemical quenching in comparison with the mesophile Chlamydomonas reinhardtii, when grown with low-salt, which is due to the lower proton conductivity across the thylakoid membrane. Significance of the C. raudensis UWO241 traits found in the low salinity culture are implicated with their natural habitats, including the high salinity and extremely stable light environments.
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Affiliation(s)
- Kenji Takizawa
- Institute of Low Temperature Science, Hokkaido University, Sapporo, 060-0819, Japan
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