International Journal of Aquaculture, 2025, Vol.15, No.4, 165-174 http://www.aquapublisher.com/index.php/ija 165 Research Insight Open Access Mechanisms of Algal Toxin Production: From Genes to Environmental Triggers Bing Wang, Qikun Huang Tropical Microbial Resources Research Center, Cuixi Academy of Biotechnology, Zhuji, 311800, Zhejiang, China Corresponding author: qikun.huang@cuixi.org International Journal of Aquaculture, 2025, Vol.15, No.4 doi: 10.5376/ija.2025.15.0016 Received: 12 May, 2025 Accepted: 25 Jun., 2025 Published: 10 Jul., 2025 Copyright © 2025 Wang and Huang, 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 B., and Huang Q.K., 2025, Mechanisms of algal toxin production: from genes to environmental triggers, International Journal of Aquaculture, 15(4): 165-174 (doi: 10.5376/ija.2025.15.0016) Abstract Algae toxins are toxic secondary metabolites produced by algae during water blooming, with a variety of chemical structure types and toxicological effects. With the eutrophication of water bodies and the intensification of climate change, harmful algae blooms in freshwater and marine ecosystems around the world occur frequently and releases a large number of toxins, posing a serious threat to ecosystems and human health. In order to reveal the internal mechanism of algatoxin production, researchers started from genetic and environmental factors and carried out multiomic studies such as genome, transcriptome, metabolomic and ecological experiments. This study reviews the classification, chemical structure and mechanism of action of common algae toxins, explores the ecological function of toxins in algae and the food chain migration process; summarizes the discovery and characteristics of genes and gene clusters related to algae toxin biosynthesis; analyzes the impact of environmental factors such as nutrients, light, temperature, hydrodynamics and biological interactions on the production of toxins, as well as the latest progress in toxin monitoring and prediction based on molecular markers, remote sensing and big data. Finally, a prospect is proposed for the insufficient progress of the current research, in order to provide a theoretical basis for algatoxin risk assessment, ecological management and prevention and control strategies. Keywords Algae toxins; Gene clusters; Molecular regulation; Environmental factors; Monitoring and prediction 1 Introduction Algae toxins are toxic secondary metabolites produced by toxin-producing algae (mainly cyanobacteria, dinoflagellate, diatoms, etc.) in water. They can be divided into several major categories such as hepatic toxins (such as microcystins), neurotoxins (such as paralytic shellfish toxin Saxitoxin, anatoxin, amnesia shellfish toxin Domoic acid), and diarrheal toxins (such as oxalic acid, Okadaic acid) and Okadaic toxins. These toxins have complex molecular structures and diverse toxicological mechanisms (such as microcystis toxins can inhibit protein phosphatases, while marine toxins often act on ion channels) (Zhou et al., 2021; Thomas et al., 2024). Harmful Algal Blooms (HABs) are a rapid proliferation phenomenon of algae populations. They often break out under eutrophication conditions. They are accompanied by the release of a large number of algal toxins, resulting in hypoxia, reduced transparency in water, and poisoning events in aquatic organisms and humans through the food chain (Danil et al., 2021). For example, HABs can cause the water to reduce dissolved oxygen, hinder plant photosynthesis, and cause a large number of deaths such as fish and shellfish. At the same time, toxins are enriched through food webs, posing a serious threat to the safety of human drinking water and seafood. According to statistics, there are many food poisoning incidents caused by algatoxins every year around the world, which poses an ongoing challenge to public health. Therefore, in-depth research on the production mechanism of algae toxins, from gene regulation to environmental triggers, is of great significance to understanding the formation rules of harmful algae blooms and formulating pollution control strategies. This study analyzes the ecological function of toxins in algae and the food chain migration process; introduces the impact of horizontal transfer such as transposons on the diffusion of toxin production capacity; elaborates on the molecular regulatory mechanisms at the level of gene regulation and epimodal modification, as well as major signaling pathways and regulatory factors; combines the latest progress in toxin monitoring and prediction of related technologies, aiming to improve the risk assessment and ecological management capabilities of algatoxins.
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