International Journal of Aquaculture, 2025, Vol.15, No.4, 197-207 http://www.aquapublisher.com/index.php/ija 197 Review Article Open Access Epigenetic Regulation of Growth and Stress Response in Oysters Guilin Wang, Rudi Mai Tropical Marine Fisheries Research Center, Hainan Institute of Tropical Agricultural Resources, Sanya, 572025, Hainan, China Corresponding author: rudi.mai@hibio.org International Journal of Aquaculture, 2025, Vol.15, No.4 doi: 10.5376/ija.2025.15.0019 Received: 09 Jun., 2025 Accepted: 28 Jul., 2025 Published: 12 Aug., 2025 Copyright © 2025 Wang and Mai, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Wang G.L., and Mai R.D., 2025, Epigenetic regulation of growth and stress response in oysters, International Journal of Aquaculture, 15(4): 197-207 (doi: 10.5376/ija.2025.15.0019) Abstract Epigenetics provides a new perspective to explain how the genome regulates biological phenotype without changing DNA sequences. As an important breeding shellfish, oysters (oysters) have their growth rate and stress resistance directly affect economic benefits and ecological functions. In recent years, research has found that epigenetic mechanisms such as DNA methylation, histone modification and non-coding RNA are widely involved in the growth and development of oysters and the environmental stress response. This study reviews the physiological basis of oyster growth and stress resistance, focusing on the role of DNA methylation in the regulation of key growth gene expression, the effect of histone covalent modification on nutritional metabolism and energy distribution, and the functions of non-coding RNAs such as miRNA, lncRNA, and piRNA in regulatory networks. In addition, we summarize how epigenetic mechanisms affect oyster adaptation to environmental stresses such as temperature, salinity, pathogens, etc., including the possible role of epigenetic memory in transgenerational stress resistance. Epigenetic regulation is an important frontier field for understanding the genetics and environmental adaptation of oyster traits, and has potential guiding significance for cultivating high-yield, stress-resistant oyster varieties. Keywords Oysters; Stress resistance; DNA methylation; Non-coding RNA; Epigeneticss 1 Introduction Oysters occupy an important position in the global aquaculture industry. In China, shellfish (including oysters) farming output accounts for about 70% of the total seawater farming output. Oysters not only have significant economic value, but are also a key species in marine ecosystems, maintaining ecological balance by filtering water bodies and building reefs. The rapid growth and strong stress-resistant oyster varieties are important goals pursued by the breeding industry. The growth rate directly affects the breeding cycle and yield, and stress-resistant determines the survival rate of oysters against environmental fluctuations and disease invasion. However, disease remains one of the biggest threats in oyster farming at present, with annual losses caused by diseases accounting for the first place in economic losses for aquaculture. For example, diseases such as "Pacific Oyster Death Syndrome" have caused large-scale oyster deaths. Therefore, improving the ability of oysters to resist diseases and stress resistance is equally important as promoting their rapid growth, and has become the key direction of aquatic scientific research. Traditional genetic breeding methods play an important role in oyster growth and improvement of stress resistance traits, but relying solely on gene sequence variations is difficult to explain all phenotypic differences. In recent years, epigenetics has attracted attention as another layer of mechanism for genome regulation. Epigenetic regulation does not change DNA base sequences, but can hereditically affect gene expression and phenotype (Zhang et al., 2017). Studies have shown that most aquaculture traits are regulated by genetics and epigenetics, and the two should be studied in combination. For example, phenotypic plasticity caused by environmental factors is often mediated by epigenetic modifications, and its effects can be transmitted to offspring to some extent. The rapid increase in the emphasis on epigenetics in the aquatic field is considered to be a new way to improve traits beyond genetic breeding. Some studies have reviewed new advances in marine environmental epigenetics and pointed out that epigenetics is of great significance in the adaptive evolution of marine invertebrates (Gawra et al., 2023). Therefore, in-depth study of the epigenetic mechanisms of oyster growth and stress resistance will
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