RRC ID 74846
Author Decelle J, Probert I, Bittner L, Desdevises Y, Colin S, de Vargas C, Galí M, Simó R, Not F.
Title An original mode of symbiosis in open ocean plankton.
Journal Proc Natl Acad Sci U S A
Abstract Symbiotic relationships are widespread in nature and are fundamental for ecosystem functioning and the evolution of biodiversity. In marine environments, photosymbiosis with microalgae is best known for sustaining benthic coral reef ecosystems. Despite the importance of oceanic microbiota in global ecology and biogeochemical cycles, symbioses are poorly characterized in open ocean plankton. Here, we describe a widespread symbiotic association between Acantharia biomineralizing microorganisms that are abundant grazers in plankton communities, and members of the haptophyte genus Phaeocystis that are cosmopolitan bloom-forming microalgae. Cophylogenetic analyses demonstrate that symbiont biogeography, rather than host taxonomy, is the main determinant of the association. Molecular dating places the origin of this photosymbiosis in the Jurassic (ca. 175 Mya), a period of accentuated marine oligotrophy. Measurements of intracellular dimethylated sulfur indicate that the host likely profits from antioxidant protection provided by the symbionts as an adaptation to life in transparent oligotrophic surface waters. In contrast to terrestrial and marine symbioses characterized to date, the symbiont reported in this association is extremely abundant and ecologically active in its free-living phase. In the vast and barren open ocean, partnership with photosymbionts that have extensive free-living populations is likely an advantageous strategy for hosts that rely on such interactions. Discovery of the Acantharia-Phaeocystis association contrasts with the widely held view that symbionts are specialized organisms that are rare and ecologically passive outside the host.
Volume 109(44)
Pages 18000-5
Published 2012-10-30
DOI 10.1073/pnas.1212303109
PII 1212303109
PMID 23071304
PMC PMC3497740
MeSH Biodiversity Molecular Sequence Data Oceans and Seas Plankton / classification Plankton / physiology* Symbiosis*
IF 9.412
Algae NIES-388 NIES-1396