Speakers

Biography

Kinga Kania is a PhD student at the University of Warsaw. My main topic of interest is understanding the mechanisms responsible for acclimating the photosynthetic apparatus to cold in psychrotolerant organisms. I focused mainly on the green algae Coccomyxa subellipsoidea C-169.

Abstract

Coccomyxa subellipsoidea C-169 is a unicellular green alga adapted to a challenging Antarctic environment. It is a psychrotolerant (with optimum growth temperature 20°C) characterized by a wide range of temperature tolerances (up to + 30°C) and high lipid content. As the first sequenced eukaryotic microorganism from a polar environment, it can serve as an attractive model for studies of the acclimatization to different temperatures and, finally, adaptation mechanisms to cold.

These results aim to clarify the acclimatization mechanisms that enable the psychrotolerant green alga C-169 to grow in a broad temperature spectrum. The contents of various biochemical compounds in cells, the lipid composition of the entire cells' biological membranes, the thylakoid fraction, the electron transport rate, and PSII efficiency were shown. The results demonstrate an acclimatization mechanism that is specific for C. subellipsoidea and that allows the maintenance of appropriate membrane fluidity, for example, in thylakoid membranes. It is achieved almost exclusively by changes within the unsaturated fatty acid pool, like changes from C18:2 into C18:3 and C16:2 into C16:3 or vice versa. This ensures, for example, an effective transport rate through PSII and, consequently, a maximum quantum yield in cells growing at different temperatures. These findings add substantially to our understanding of the acclimatization of psychrotolerant organisms to a wide range of temperatures and prove that this process could be accomplished in a species-specific manner.

This work was supported by the National Science Centre grant 2021/41/N/NZ3/04319.