Plasticity in gene expression and fatty acid profiles of Acropora tenuis reciprocally transplanted between two water quality regimes in the central Great Barrier Reef, Australia

Abstract

To investigate plasticity in biochemical and physiological health attributes of corals, identical colony fragments of the coral Acropora tenuis, from two inshore populations, were exposed to native and novel environmental regimes. Variation in global gene expression (GE) and lipid and fatty acid (FA) composition of surviving colony fragments were quantified after four months. Major FA classes, with the exception of short-chain (C18) polyunsaturated fatty acids (PUFA), decreased in concentration when coral fragments were exposed to lower water quality regardless of their source population. In contrast, a strong effect of source population was detected in the GE profiles of all coral fragments and was enriched with genes associated with translation, ribosome biogenesis and ribosome cellular components. One cluster of co-expressed genes positively correlated with multiple individual FA and included genes involved in developmental processes and cellular pathways. This study demonstrates the strong influence of a source effect defining gene expression relating to basic biological functions, including biosynthetic processing, translation and ribosome biogenesis. However, there is plasticity in FA composition and specific genes relating to elevated health and immunity, which can respond to changes in environmental conditions. These findings suggest hope for future corals, if we can reduce anthropogenic water quality stressors.