Effects of temperature and salinity stress on DNA methylation in a highly invasive marine invertebrate, the colonial ascidian Didemnum vexillum

• Published in: PeerJ (San Francisco, CA) CA), 2018-06, Vol.6, p.e5003-e5003, Article e5003
• Main Authors: Hawes, Nicola A, Tremblay, Louis A, Pochon, Xavier, Dunphy, Brendon, Fidler, Andrew E, Smith, Kirsty F
• Format: Article
• Language: English
• Subjects: Adaptation; Ascidiacea; Climate change; Climate Change Biology; Colonies; Deoxyribonucleic acid; Didemnum; DNA; DNA methylation; Ecology; Environmental change; Environmental stress; Epigenetics; Gene expression; Genetic diversity; Genomes; High temperature; Introduced species; Invasive species; Invertebrates; Marine Biology; Marine invertebrate; Molecular Biology; Nonnative species; Phenotypic plasticity; Physiology; Rapid adaptation; Salinity; Salinity effects; Success; Survival; Temperature effects; Zoology
• ISSN: 2167-8359; 2167-8359
• DOI: 10.7717/peerj.5003

Environmentally induced epigenetic changes may contribute to phenotypic plasticity, increase adaptive potential in changing environments, and play a key role in the establishment and spread of invasive species in new habitats. In this study, we used methylation-sensitive amplified polymorphism (MSAP) to assess environmentally induced DNA methylation changes in a globally invasive clonal ascidian, . We tested the effect of increasing temperature (19, 25 and 27 °C) and decreasing salinity (34, 32, 30, 28 and 26 practical salinity units (PSU)) on global DNA methylation, growth and survival rates. Exposure to 27 °C resulted in significant changes in DNA methylation over time. Growth also decreased in colonies exposed to high temperatures, suggesting they were under thermal stress. In contrast, no differences in growth nor DNA methylation patterns were observed in colonies exposed to a decreasing salinity gradient, potentially due to prior adaptation. The results of this study show that environmental stress can induce significant global DNA methylation changes in an invasive marine invertebrate on very rapid timescales, and that this response varies depending on the type, magnitude, and duration of the stressor. Changes in genomic DNA methylation and the rate of growth may act to 'buy survival time' under stressful conditions, expanding the distribution limits of this globally invasive species.