Impact of ocean acidification on the metabolome of the brown macroalgae Lobophora rosacea from New Caledonia

• Published in: Algal Research
• Main Authors: Gaubert, Julie, Rodolfo-Metalpa, Riccardo, Greff, Stephane, Thomas, Olivier P., Payri, Claude
• Other Authors: Ecologie marine tropicale des océans Pacifique et Indien (ENTROPIE Nouvelle-Calédonie ), Institut de Recherche pour le Développement (IRD Nouvelle-Calédonie )-Délégation Ifremer de Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Nouvelle-Calédonie (UNC)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU), Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement IRD : UMR237-Centre National de la Recherche Scientifique (CNRS), Natl Univ Ireland Galway, Sch Chem, Marine Biodiscovery, Galway, Ireland, National University of Ireland Galway (NUI Galway), ANR-17-ERC2-0009,PNG-Vents,Acclimatation des coraux à l'acidification et réchauffement des océans autour de résurgences sous-marines de CO2(2017)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: brown macroalgae; LC-MS; metabolomics; ocean acidification; specialized metabolites; [SDE.MCG]Environmental Sciences/Global Changes; Ocean acidification
• Online Access: https://amu.hal.science/hal-02436395; https://amu.hal.science/hal-02436395/document; https://amu.hal.science/hal-02436395/file/Gaubert%20et%20al%202020%20Algal%20research_postprint.pdf; https://doi.org/10.1016/j.algal.2019.101783

International audience Macroalgae are critical components of coral reef ecosystems. Yet, they compete for space with corals, and in case of environmental disturbances, they are increasingly involved in phase-shifts from coral-dominated to macroalgae-dominated reefs. As regard to climate change, ocean acidification (OA) has been shown to be detrimental to corals and could favor macroalgal proliferations. However, little is known about the effects of OA on macroalgal phenotypes. Comparative metabolomic studies are particularly relevant to assess phenotypic responses of macroalgae to stress as some seaweed are known to produce a large diversity of specialized metabolites involved in various ecological functions. The main aim of our study was to explore the impact of OA on the metabolome of brown macroalgae using Lobophora rosacea as a model species. This species is widespread in New Caledonian lagoons where it is a key component of coral-algal interactions. Metabolomic changes were analyzed using Liquid Chromatography-Mass Spectrometry (UPLC-HRMS) applied to three different OA scenarii: low and variable pH over a long-term timescale (in situ at Bouraké), low and constant pH over a short-term timescale (ex situ experiment), and current pH (control). Different metabotypes were defined in diverse pH conditions, and a significant decrease in some specialized metabolites concentrations was noticed at low pH including lobophorenols B and C as well as other oxylipin derivatives. We suggest a down-regulation of metabolic pathways involving lobophorenols, in low pH conditions, or their transformation, which is in accordance with the optimal defense theory. In addition, we used Microtox ® bioassays as a proxy for macroalgal toxicity and found no significant differences between low pH and control samples. This study details the first metabolomic-based study on a fleshy macroalgae in response to OA and provides new insights for this important functional group producing a large number of metabolites in response to their close ...