The genome of the polar eukaryotic microalga Coccomyxa subellipsoidea reveals traits of cold adaptation

Guillaume Blanc, Irina Agarkova, Jane Grimwood, Alan Kuo, Andrew Brueggeman, David D. Dunigan, James Gurnon, Istvan Ladunga, Erika Lindquist, Susan Lucas, Jasmyn Pangilinan, Thomas Pröschold, Asaf Salamov, Jeremy Schmutz, Donald Weeks, Takashi Yamada, Alexandre Lomsadze, Mark Borodovsky, Jean Michel Claverie, Igor V. GrigorievJames L. Van Etten

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Abstract

Background: Little is known about the mechanisms of adaptation of life to the extreme environmental conditions encountered in polar regions. Here we present the genome sequence of a unicellular green alga from the division chlorophyta, Coccomyxa subellipsoidea C-169, which we will hereafter refer to as C-169. This is the first eukaryotic microorganism from a polar environment to have its genome sequenced.Results: The 48.8 Mb genome contained in 20 chromosomes exhibits significant synteny conservation with the chromosomes of its relatives Chlorella variabilis and Chlamydomonas reinhardtii. The order of the genes is highly reshuffled within synteny blocks, suggesting that intra-chromosomal rearrangements were more prevalent than inter-chromosomal rearrangements. Remarkably, Zepp retrotransposons occur in clusters of nested elements with strictly one cluster per chromosome probably residing at the centromere. Several protein families overrepresented in C. subellipsoidae include proteins involved in lipid metabolism, transporters, cellulose synthases and short alcohol dehydrogenases. Conversely, C-169 lacks proteins that exist in all other sequenced chlorophytes, including components of the glycosyl phosphatidyl inositol anchoring system, pyruvate phosphate dikinase and the photosystem 1 reaction center subunit N (PsaN).Conclusions: We suggest that some of these gene losses and gains could have contributed to adaptation to low temperatures. Comparison of these genomic features with the adaptive strategies of psychrophilic microbes suggests that prokaryotes and eukaryotes followed comparable evolutionary routes to adapt to cold environments.

Original languageEnglish (US)
Article numberR39
JournalGenome biology
Volume13
Issue number5
DOIs
StatePublished - May 25 2012

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ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics
  • Cell Biology

Cite this

Blanc, G., Agarkova, I., Grimwood, J., Kuo, A., Brueggeman, A., Dunigan, D. D., Gurnon, J., Ladunga, I., Lindquist, E., Lucas, S., Pangilinan, J., Pröschold, T., Salamov, A., Schmutz, J., Weeks, D., Yamada, T., Lomsadze, A., Borodovsky, M., Claverie, J. M., ... Van Etten, J. L. (2012). The genome of the polar eukaryotic microalga Coccomyxa subellipsoidea reveals traits of cold adaptation. Genome biology, 13(5), [R39]. https://doi.org/10.1186/gb-2012-13-5-r39