Dicrateria rotunda MicroPolar 03 F24PG5 RCC4501 in culture [Image credit: Louis Graf]

CSP Proposal 2022 "The Haptophyte Genome Project" aims to expand the phylogenetic breadth of sequenced Haptophyte genomes, particularly freshwater samples. The Haptophytes are an ancient and complex lineage of eukaryotic algae of immense ecological importance, forming the second most significant contribution to planetary eukaryotic photosynthesis after diatoms [1, 2]. Sequencing genomes and transcriptomes of phylogenetically diverse haptophytes and relevant outgroups will address long-standing questions pertaining to: 1) the phylogenetic framework and genomic diversity of species selected from freshwater, salty continental and marine environments, 2) the transition of haptophytes between marine and freshwater systems, 3) the phylogenetic composition of the haptophyte genome with particular regard to its chloroplast, 4) key components involved in biomineralization, alkenone biosynthesis, and toxin production, 5) cellular machinery associated with mixotrophy, and 6) prevalence of pan-genomes, relevant to a heating ocean.

Dicrateria rotunda MicroPolar 03 F24PG5 RCC4501

Dicrateria rotunda MicroPolar 03 F24PG5 RCC4501 is a boreal/Arctic isolate of the amended genus Dicrateria/Imantonia [3,4] collected from the Greenland Sea (latitude 79.76 °N, longitude 6.20 °E) as part of the MicroPolar cruise [5]. Preliminary analysis in-lab suggests viability between 4 and 19 °C, although with optimal growth rates between 12 and 19 °C. The 18S rDNA sequence of this strain shows close (100%) identity to other sequenced isolates from Alaska (RCC2298), Svalbard (RCC4500, RCC4780), South Africa (RCC704) and Red Sea (RCC4477) waters.

References

1. Penot, M. et al. (2022) Genomic and meta-genomic insights into the functions, diversity and global distribution of haptophyte algae. Appl Phycol. 3. p. 340-359. https://doi.org/10.1080/26388081.2022.2103732
2. Read, B.A. et al. (2013) Pan genome of the phytoplankton Emiliania underpins its global distribution. Nature. 499(7457): p. 209-13. https://doi.org/10.1038/nature12221
3. M.D. Guiry in Guiry, M.D. & Guiry, G.M. 02 April 2025. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org/search/species/detail/?species_id=148690; searched on 28 April 2025.
4. Bendif, El M., Probert, I., Schroeder, D.C. & Vargas, C de. (2014) Erratum to: On the description of Tisochrysis lutea; gen. nov. sp. nov. and Isochrysis nuda sp. nov. in the Isochrysidales, and the transfer of Dicrateria to the Prymnesiales (Haptophyta). Journal of Applied Phycology 26: 1617. https://doi.org/10.1007/s10811-014-0284-8
5. Egge, E. et al. (2021) An 18S V4 rRNA metabarcoding dataset of protist diversity in the Atlantic inflow to the Arctic Ocean, through the year and down to 1000 m depth. Earth System Science Data. 13(10): p. 4913-4928. https://doi.org/10.17882/79823