Efecto de la translocación de glucosa sobre el metabolismo de STYLOPHORA PISTILLATA en la relación mutualista Cnidaria-microalga, empleando modelos estequiométricos.

Abstract

Stylophora pistillata coral is a branching coral species distributed in the Indian and Pacific Oceans. Like other corals, it establishes a symbiotic relationship with dinoflagellates from the Symbiodiniaceae family, allowing them to survive in oligotrophic tropical and subtropical waters and contributing to the formation of coral reef ecosystems, one of the most diverse on the planet. However, this species faces several threats, such as climate change, increasing water temperature, eutrophication pollution, and fishing, which can lead to coral mortality and population decline, affecting the coral reef ecosystem. To better understand its metabolism and study how the availability of carbon sources affects energydemanding processes like calcification, this research evaluated the entry of the photosynthetic product glucose into the metabolism of Stylophora pistillata coral. The investigation was carried out using a stoichiometric constraint-based model, integrating the genome with its functional annotation that reconstructed its metabolic network, obtaining both a symbiotic and an aposymbiotic scenario. The model demonstrated differences in metabolic flux distributions between each scenario, as blocking the entry of glucose and ammonium resulted in reduced production of amino acid biomass and calcium. These results demonstrate the impact of mutualistic symbiosis on processes such as calcification, as symbiosis in equilibrium exhibits a favorable calcification rate to ultimately form the 3D skeletal structure that supports coral reef formation. However, in the aposymbiotic state, symbiosis is completely disrupted as the host cannot recycle ammonium through pathways like GS/GOGAT, which are precursors for non-essential amino acids required for the organic matrix of the skeleton and skeletal formation. It is evident that a very low amount of biomass metabolites is produced in this state, as the host obtains the amino acid choline from its diet.