V-type H+-ATPase in the symbiosome membrane is a conserved mechanism for host control of photosynthesis in anthozoan photosymbioses

Katie L Barott; Angus B Thies; Martin Tresguerres

doi:10.1098/rsos.211449

V-type H⁺-ATPase in the symbiosome membrane is a conserved mechanism for host control of photosynthesis in anthozoan photosymbioses

R Soc Open Sci. 2022 Jan 26;9(1):211449. doi: 10.1098/rsos.211449. eCollection 2022 Jan.

Authors

Katie L Barott¹, Angus B Thies², Martin Tresguerres²

Affiliations

¹ Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
² Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.

Abstract

In reef-building corals (order Scleractinia) and giant clams (phylum Molluca), V-type H⁺-ATPase (VHA) in host cells is part of a carbon concentrating mechanism (CCM) that regulates photosynthetic rates of their symbiotic algae. Here, we show that VHA plays a similar role in the sea anemone Anemonia majano, a member of the order Actinaria and sister group to the Scleractinia, which in contrast to their colonial calcifying coral relatives is a solitary, soft-bodied taxa. Western blotting and immunofluorescence revealed that VHA was abundantly present in the host-derived symbiosome membrane surrounding the photosymbionts. Pharmacological inhibition of VHA activity in individual anemones resulted in an approximately 80% decrease of photosynthetic O₂ production. These results extend the presence of a host-controlled VHA-dependent CCM to non-calcifying cnidarians of the order Actiniaria, suggesting it is widespread among photosymbiosis between aquatic invertebrates and Symbiodiniaceae algae.

Keywords: Symbiodiniaceae; carbon concentrating mechanism; sea anemone.