Pavlova sp. CC15 RCC6257 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.

Pavlova sp. CC15 RCC6257

Pavlova sp. CC15 RCC6257 is a tropical isolate of the order Pavlovophyceae collected from the Caribbean Sea (latitude 18.57 °N, longitude -74.57 °E) as part of the CaraCalhis expedition. Preliminary analysis in-lab suggests viability between 12 and 32 °C, although with optimal growth rates between 28 and 32 °C. The 18S rDNA sequence of this strain suggests it belongs to Pavlovophyceae Clade 3 as defined by Bendif et al. [3], with close proximity to the described species P. granifera and P. pinguis.

References

1. Penot, M., et al., Genomic and meta-genomic insights into the functions, diversity and global distribution of haptophyte algae. Appl Phycol, 2022. 3. p. 340-359. https://doi.org/10.1080/26388081.2022.2103732
2. Read, B.A., et al., Pan genome of the phytoplankton Emiliania underpins its global distribution. Nature, 2013. 499(7457): p. 209-13. https://doi.org/10.1038/nature12221
3. Bendif, e.M., et al., Integrative taxonomy of the Pavlovophyceae (Haptophyta): a reassessment. Protist, 2011. 162(5): p. 738-61. https://doi.org/10.1016/j.protis.2011.05.001