Metabolite profiling of symbiont and host during thermal stress and bleaching in a model cnidarian-dinoflagellate symbiosis

Hillyer, K. E., Tumanov, S., Villas-Boas, S. and Davy, S. K. (2016) Metabolite profiling of symbiont and host during thermal stress and bleaching in a model cnidarian-dinoflagellate symbiosis. Journal of Experimental Biology, 219(4), pp. 516-527. (doi: 10.1242/jeb.128660) (PMID:26685173)

Abstract

Bleaching (dinoflagellate symbiont loss) is one of the greatest threats facing coral reefs. The functional cnidarian–dinoflagellate symbiosis, which forms coral reefs, is based on the bi-directional exchange of nutrients. During thermal stress this exchange breaks down; however, major gaps remain in our understanding of the roles of free metabolite pools in symbiosis and homeostasis. In this study we applied gas chromatography–mass spectrometry (GC-MS) to explore thermally induced changes in intracellular pools of amino and non-amino organic acids in each partner of the model sea anemone Aiptasia sp. and its dinoflagellate symbiont. Elevated temperatures (32°C for 6 days) resulted in symbiont photoinhibition and bleaching. Thermal stress induced distinct changes in the metabolite profiles of both partners, associated with alterations to central metabolism, oxidative state, cell structure, biosynthesis and signalling. Principally, we detected elevated pools of polyunsaturated fatty acids (PUFAs) in the symbiont, indicative of modifications to lipogenesis/lysis, membrane structure and nitrogen assimilation. In contrast, reductions of multiple PUFAs were detected in host pools, indicative of increased metabolism, peroxidation and/or reduced translocation of these groups. Accumulations of glycolysis intermediates were also observed in both partners, associated with photoinhibition and downstream reductions in carbohydrate metabolism. Correspondingly, we detected accumulations of amino acids and intermediate groups in both partners, with roles in gluconeogenesis and acclimation responses to oxidative stress. These data further our understanding of cellular responses to thermal stress in the symbiosis and generate hypotheses relating to the secondary roles of a number of compounds in homeostasis and heat-stress resistance.

• Item Type: Articles
• Additional Information: This research was supported by a Marsden Fund grant (contract number VUW0902) awarded to S.K.D. This work fulfils part of the requirements for a PhD funded by a Victoria PhD Scholarship awarded to K.E.H.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Tumanov, Dr Sergey
• Authors: Hillyer, K. E., Tumanov, S., Villas-Boas, S., and Davy, S. K.
• College/School: College of Medical Veterinary and Life Sciences > School of Cancer Sciences
• Journal Name: Journal of Experimental Biology
• Publisher: Company of Biologists
• ISSN: 0022-0949
• ISSN (Online): 1477-9145