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

Abstract

BackgroundLittle 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.ResultsThe 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).ConclusionsWe 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.

Temperature-dependent growth rate and photosynthetic performance of Antarctic symbiotic alga Trebouxia sp. cultivated in a bioreactor

“…During the first 7 day of cultivation Trebouxia sp., similarly to K. antarctica exhibited higher OD in 15°C, while further cultivation led to more rapid growth in 10 then 15°C. Some unicellular algae from Antarctica, however, exhibit higher growth rates in cultivation temperature above 20°C, as reported by Chen et al (2012) for Stichococcus (Trebouxiophyceae) and Blanc et al (2012) for polar alga Coccomyxa subellipsoidea.…”

Algal photoreceptors: in vivo functions and potential applications

“…These phototropins come from Chlorella variabilis (Genbank accession number: EFN51280, Blanc et al 2010), Micromonas pusilla CCMP1545 (Genbank accession number: XM_003063488, Worden et al 2009), Ostreococcus lucimarinus CCE9901 (Genbank accession number: XP_001421797, Palenik et al 2007), Coccomyxa subellipsoidea C-169 (Genbank accession number: EIE23763, Blanc et al 2012) and Ostreococcus tauri (Genbank accession number: CAL58288).…”

“…During evolution, these organisms also developed diverse light-sensitive proteins, so-called photoreceptors, and the corresponding signaling pathways for algal model systems with available genome and transcriptome information are Chlamydomonas reinhardtii (C. reinhardtii) , Volvox carteri (V. carteri) (Prochnik et al 2010), Phaeodactylum tricornutum (Bowler et al 2008), Ostreococcus tauri (Derelle et al 2006), Ostreococcus lucimarinus (Palenik et al 2007), Thalassiosira pseudonana (Armbrust et al 2004), Cyanidioschyzon merolae (Matsuzaki et al 2004), Nannochloropsis (Radakovits et al 2012;Vieler et al 2012), Bathycoccus prasinos (Moreau et al 2012) and Coccomyxa subellipsoidea (Blanc et al 2012). The production of additional genome and transcriptome data of the algae Haematococcus pluvialis, Gonium pectorale, Eudorina elegans and Pleodorina starii ( Fig.…”

Agrigenomics for Microalgal Biofuel Production: An Overview of Various Bioinformatics Resources and Recent Studies to Link OMICS to Bioenergy and Bioeconomy

“…To date, the whole genome sequences of more than ten microalgae have been generated (Guarnieri et al, 2011;Liu and Benning, 2012;) (Table 1). These includes the Cyanidioschyzon merolae 10D (Matsuzaki et al, 2004), Phaeodactylum tricornutum CCP1055/1 , Thalassiosira pseudonana CCMP1335 (Armbrust et al, 2004), Guillardia theta CCMP2712 (Curtis et al, 2012), Chlamydomonas reinhardtii CC-503 (Merchant et al, 2007), Ostreococcus tauri OTH95 (Derelle et al, 2006), Ostreococcus lucimarinus CCE9901 (Palenik et al, 2007), two strains of Micromonas pusilla, RCC299 and CCMP1545 (Worden et al, 2009), Bathycoccus prasinos RCC1105 (Moreau et al, 2012), Volvox carteri UTEX2908 (Prochnik et al, 2010), Chlorella vulgaris NC64A (Blanc et al, 2010), Coccomyxa subellipsoidea C-169 (Blanc et al, 2012), Ectocarpus siliculosus EC32 (Cock et al, 2010), Aureococcus anophagefferens CCMP1984 (Gobler et al, 2011), Nannochloropsis gaditana (Radakovits et al, 2012), and Bigelowiella natans CCMP2755 (Curtis et al, 2012). Other algal genomes in the sequencing pipeline are Ostreococcus sp RCC809, Botryococcus braunii Berkeley strain, Dunaliella salina CCAP19/18, Galdieria sulphuraria, Chondrus crispus, Fragilariopsis cylindrus CCMP1102, Pseudo-nitzchia multiseries CLN-47, Emiliana huxleyi CCMP1516 (Radakovits et al, 2010;Tirichine and Bowler, 2011).…”