Norman Hüner, PhD
Life at the Edge: Photosynthetic Adaptation and Phenotypic Plasticity in Extreme Environments
Surprising to most, the Earth is generally a cold place. Eighty per cent of our biosphere is permanently below 5°C, including most of the oceans and the polar and alpine regions. Antarctica and its surrounding oceans as well as the Arctic, once assumed to be devoid of biodiversity has been shown to be teeming with diverse life forms. Consequently, these organisms represent some of the least studied but are crucial components to one of the most important ecosystems on the planet. Eukaryotic algae and cyanobacteria are the dominant life forms in these cold habitats, many of which are psychrophiles, that is, obligately adapted to low temperature but die at “normal” temperatures. The Antarctic green alga, Chlamydomonas sp. UWO 241 is the primary biological system under study in my laboratory and has become a model system for study of life at the edge.
A photoautotrophic life style requires the integration of photophysical, photochemical and biochemical processes involved in the conversion of light energy into stable storage forms of carbon for growth and metabolism. The photophysical processes of light absorption and energy trapping (energy source) occur on a 10-12 to 10-6s time scale and are temperature insensitive. In contrast, biochemical reactions involved energy conversion and storage (energy sink) are temperature sensitive and occur on time scale that is 10 orders of magnitude slower. These disparate rates can expose photoautotrophs to excess excitation energy (EEE) which result in a potential cellular energy imbalance measured as excitation pressure. Consequently, an essential component in the evolution of photoautotrophic psychrophiles must be the maintenance of cellular energy balance between source and sink.
The long-term goal of my research programme is the complete physiological, biochemical and molecular characterization of Chlamydomonas sp. UWO 241 with respect to the structure and function of its novel photosynthetic apparatus in order to explain how UWO 241 maintains cellular energy balance under its unique and extreme environment as well as to elucidate the molecular basis of psychrophily. This is accomplished by combining physiological, biochemical, biophysical and molecular techniques and approaches.
Degrees and Institutions
- Biology 3660B- Advanced Plant Physiology and Biochemistry
- Biology 4608F- Environmental Plant Physiology
- Biology 4999E- Honours Thesis Projects
- Scholars Elective 3303E- Research Project
- Biology 9610A – Plant Stress Biology
- Morgan, R. M., Ivanov, A. G., Priscu, J. C., Maxwell, D. P., Hüner, N. P. A. (1998) Structure and composition of the photochemical apparatus of Antarctic green alga, Chlamydomonas sp. UWO 241. Photosyn. Res. 56: 303-314.
- Morgan-Kiss R, Ivanov A G, Hüner NPA (2001) The Antarctic psychrophile, Chlamydomonas sp. UWO 241, is deficient in state I-state II transitions. Planta 214: 435-445.
- Hüner, N P A, Oquist G, Melis A (2003) Photostasis in plants, green algae and cyanobacteria: the role of light harvesting antenna complexes. Advances in Photosynthesis and Respiration. Light Harvesting Antennas in Photosynthesis (Green BR, Parson WW, eds). Vol. 13: 401-421. Kluwer Academic Publishers, Dordrecht.
- Gudynaite-Savitch, L, Gretes,M, Morgan-Kiss, R, Savitch, L, Simmonds, J, Kohalmi, S, Hüner, NPA (2006) Cytochrome f from the Antarctic psychrophile, Chlamydomonas sp. UWO 241: structure, sequence, and complementation in the mesophile, Chlamydomonas reinhardtii. Mol. Genet. Genomics 275: 387-398.
- Morgan-Kiss, RM, Priscu, JC, Pocock, T, Gudynaite-Savitch, L, Hüner, NPA (2006) Adaptation and acclimation of photosynthetic microorganisms to permanently cold environments. Microbiol. Mol. Biol. Rev. 70: 222-252.
- Ensminger,I, Busch,F, Hüner,NPA (2006) Photostasis and cold acclimation: sensing low temperature through photosynthesis. Physiol. Plant. 126: 28-44.
- PocockTH. Koziak A, Rosso D, Falk S, Hüner NPA (2007) Chlamydomonas sp.(UWO 241), chlorophyceae, exhibits the capacity for rapid d1 repair in response to chronic photoinhibition at low temperature. J. Phycol. 43: 924-936.
- Szyszka, B., Ivanov, A. G., Hüner, NPA (2007) Psychrophily is associated with differential energy partitioning, photosystem stoichiometry and polypeptide phosphorylation in Chlamydomonas sp. UWO 241. Biochim. Biophys. Acta (Bioenergetics) 1767: 789-800.
- Possmayer, M, Berardi, G, Beall, BFN, Trick, CG, Hüner, NPA, Maxwell DP (2011) Plasticity of the psychrophilic green alga Chlamydomonas sp. (UWO 241) (Chlorophyta) to supraoptimal temperature stress. J. Phycol. 47: 1098-1109.
- Hüner NPA, Grodzinski B (2011) Photosynthesis and photoautotrophy. Comprehensive Biotechnology,Second Edition, In: Murray Moo-Young (ed.), Elsevier.Vol. 1: 315-322.
- Kurepin, L, Dahal, K, Savitch, L, Singh, J, Bode, R, Ivanov, A, Hurry, V, Hüner, NPA (2013) Role of CBFs as integrators of chloroplast redox, phytochrome and plant hormone signaling during cold acclimation. Int. J. Mol. Sci. 14: 12729-12763.
- Hollis L, Hüner NPA (2014) Retrograde operational sensing and signalling pathways maintain photostasis in green algae, cyanobacteria and terrestrial plants. Trends Photochem. Photobiol. 16: 47-61.
- Szyszka-Mroz, B, Pittock, P, Ivanov, AG, Lajoie, G, Hüner, NPA (2015) The Antarctic psychrophile Chlamydomonas sp. UWO 241 preferentially phosphorylates a photosystem I-cytochrome b6/f supercomplex. Plant Physiol. 169: 717-736.
- Bode R, Ivanov AG, Hüner NPA (2016) Global transcriptome analyses provide evidence that chloroplast redox state contributes to intracellular as well as long-distance signalling in response to stress and acclimation in Arabidopsis. Photosyn. Res. 128: 287-312.
- Possmayer, M, Gupta, RK, Szyszka‐Mroz, B, Maxwell, DP, Lachance, M-A, Hüner, NPA, Smith, DR (2016) Resolving the phylogenetic relationship between Chlamydomonas sp. UWO 241 and Chlamydomonas raudensis SAG 49.72 (Chlorophyceae) with nuclear and plastid DNA sequences. J. Phycol. 52: 305-310.