Symbiosis-dependent gene expression in coral–dinoflagellate association: cloning and characterization of a P-type H⁺-ATPase gene

Abstract

We report the molecular cloning of a H þ -ATPase in the symbiotic dinoflagellate, Symbiodinium sp. previously suggested by pharmacological studies to be involved in carbon-concentrating mechanism used by zooxanthellae when they are in symbiosis with corals. This gene encodes a protein of 975 amino acids with a calculated mass of about 105 kDa. The structure of the protein shows a typical Ptype H þ -ATPase structure (type IIIa plasma membrane H þ -ATPases) and phylogenetic analyses show that this new proton pump groups with diatoms in the Chromoalveolates group. This Symbiodinium H þ -ATPase is specifically expressed when zooxanthellae are engaged in a symbiotic relationship with the coral partner but not in free-living dinoflagellates. This proton pump, therefore, could be involved in the acidification of the perisymbiotic space leading to bicarbonate dehydration by carbonic anhydrase activity in order to supply inorganic carbon for photosynthesis as suggested by earlier studies. To our knowledge, this work provides the first example of a symbiosis-dependent gene in zooxanthellae and confirms the importance of H þ -ATPase in coral-dinoflagellate symbiosis.

Coral host cells acidify symbiotic algal microenvironment to promote photosynthesis

“…2), suggesting that the regions with the brighter LSG signal are due to increased VHA activity. The pH of the symbiosome lumen did not neutralize in the presence of bafilomycin after 30 min, indicating that either more time was required to reach neutral pH or an additional mechanism(s), such as the symbiosis-dependent Symbiodinium P-type H + -ATPase (25), may contribute to acidification of the algal microenvironment.…”

Identification of uterine ion transporters for mineralisation precursors of the avian eggshell

“…This VAT is present in many membranes of organelles and also frequently in the plasma membranes of renal cells or osteoclasts [70]. VAT is therefore a good candidate for transferring protons to plasma in the hen uterine glandular cell, especially as this VAT was revealed in other species producing CaCO 3 biominerals and shown to export H + during mineralisation [71,72]. This proton ATPase extrudes H + across the basolateral membrane of pancreatic duct epithelium [57] which is secreting high amounts of HCO 3 - using mechanisms quite similar to uterine glandular cells.…”

Marine Invertebrate Larvae Associated with Symbiodinium: A Mutualism from the Start?

“…While yet to be applied for larval studies, symbiosis-specific genes have been identified recently in Aiptasia anemones (Bucher et al, 2016;Wolfowicz et al, 2016). From the symbiont perspective, apart from the identification of protein kinases that may be involved in the establishment of symbiosis (Rosic et al, 2014), a symbiosisspecific gene was identified in Symbiodinium clade A, an H + -ATPase (Bertucci et al, 2010). This gene is the only symbiosisspecific gene that had its expression verified in Symbiodinium associated with invertebrate larvae (Mies et al, 2017b,c).…”