Microplastics induce dose-specific transcriptomic disruptions in energy metabolism and immunity of the pearl oyster Pinctada margaritifera
|Author(s)||Gardon Tony1, Morvan Lucie1, Huvet Arnaud2, Quillien Virgile1, 2, Soyez Claude1, Le Moullac Gilles1, Le Luyer Jeremy1|
|Affiliation(s)||1 : Ifremer, Institut Louis‐Malardé, IRD, Univ Polynésie Française, EIO, F-98719, Taravao, Tahiti, Polynésie française, France
2 : Univ Brest, Ifremer, CNRS, IRD, LEMAR, F-29280, Plouzané, France
|Source||Environmental Pollution (0269-7491) (Elsevier BV), 2020-11 , Vol. 266 , N. Part 3 , P. 115180 (9p.)|
|Keyword(s)||Microbeads, Marine bivalve, Differentially expressed genes, Stress response, Energy-limited tolerance|
A combined approach integrating bioenergetics and major biological activities is essential to properly understand the impact of microplastics (MP) on marine organisms. Following experimental exposure of polystyrene microbeads (micro-PS of 6 and 10 μm) at 0.25, 2.5, and 25 μg L−1, which demonstrated a dose-dependent decrease of energy balance in the pearl oyster Pinctada margaritifera, a transcriptomic study was conducted on mantle tissue. Transcriptomic data helped us to decipher the molecular mechanisms involved in P. margaritifera responses to micro-PS and search more broadly for effects on energetically expensive maintenance functions. Genes related to the detoxification process were impacted by long-term micro-PS exposure through a decrease in antioxidant response functioning, most likely leading to oxidative stress and damage, especially at higher micro-PS doses. The immune response was also found to be dose-specific, with a stress-related activity stimulated by the lowest dose present after a 2-month exposure period. This stress response was not observed following exposure to higher doses, reflecting an energy-limited capacity of pearl oysters to cope with prolonged stress and a dramatic shift to adjust to pessimum conditions, mostly limited and hampered by a lowered energetic budget. This preliminary experiment lays the foundation for exploring pathways and gene expression in P. margaritifera, and marine mollusks in general, under MP exposure. We also propose a conceptual framework to properly assess realistic MP effects on organisms and population resilience in future investigations.