REVIEW: Cyanidiales as Polyextreme Eukaryotes

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Igor N. Stadnichuk^1,a* and Ivan V. Tropin²

¹Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127726 Moscow, Russia

²Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia

^* To whom correspondence should be addressed.

Received December 29, 2021; Revised March 28, 2022; Accepted April 24, 2022

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Cyanidiales were named enigmatic microalgae due to their unique polyextreme properties, considered for a very long time unattainable for eukaryotes. Cyanidiales mainly inhabit hot sulfuric springs with high acidity (pH 0-4), temperatures up to 56°C, and ability to survive in the presence of dissolved heavy metals. Owing to the minimal for eukaryotes genome size, Cyanidiales have become one of the most important research objects in plant cell physiology, biochemistry, molecular biology, phylogenomics, and evolutionary biology. They play an important role in studying many aspects of oxygenic photosynthesis and chloroplasts origin. The ability to survive in stressful habitats and the corresponding metabolic pathways were acquired by Cyanidiales from archaea and bacteria via horizontal gene transfer (HGT). Thus, the possibility of gene transfer from prokaryotes to eukaryotes was discovered, which was a new step in understanding of the origin of eukaryotic cell.

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KEY WORDS: acido-thermophily, microalgae, Cyanidiales, Cyanidium caldarium, Cyanidioschyzon merolae, Galdieria sulphuraria

DOI: 10.1134/S000629792205008X

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