Publications

Genome-resolved biogeography of Phaeocystales, cosmopolitan bloom-forming algae

Füssy Z, Lampe RH, Arrigo KR, Barry K, Brisbin MM, Brussaard CPD, Decelle J, de Vargas C, Ditullio GR, Elbourne LDH, Frischer ME, Goodstein DM, Grigoriev IV, Hayes RD, Healey AL, James CC, Jenkins JW, Juery C, Kumar M, Kustka AB, Maumus F, Novák Vanclová AMG, Oborník M, Paulsen IT, Probert I, Saito MA, Schmutz J, Skalický T, Tec-Campos D, Tomelka H, Věchtová P, Venepally P, Wilson-Mortier B, Zengler K, Zheng H, Allen AE

PMID: 41022706

Abstract

Phaeocystales, comprising the genus Phaeocystis and an uncharacterized sister lineage, are nanoplanktonic haptophytes widespread in the global ocean. Several species form mucilaginous colonies and influence key biogeochemical cycles, yet their underlying diversity and ecological strategies remain underexplored. Here, we present new genomic data from 13 strains, including three high-quality reference genomes (N50 > 30 kbp), and integrate previous metagenome-assembled genomes to resolve a robust phylogeny. Divergence timing of P. antarctica aligns with Miocene cooling and Southern Ocean isolation. Genomic traits reveal metabolic flexibility, including mixotrophic nitrogen acquisition in temperate waters and gene expansions linked to polar nutrient adaptation. Concordantly, transcriptomic comparisons between temperate and polar Phaeocystis suggest Southern Ocean populations experience iron and B limitation. We also identify signatures of horizontal gene transfer and endogenous giant virus/virophage insertions. Together, these findings highlight Phaeocystales as an ecologically versatile and geographically widespread lineage shaped by evolutionary innovation and adaptation to contrasting environmental stressors.