microorganisms Review The Genetic Basis of Toxin Biosynthesis in Dinoflagellates Arjun Verma 1,* , Abanti Barua 1,2, Rendy Ruvindy 1, Henna Savela 3, Penelope A. Ajani 1 and Shauna A. Murray 1 1 Climate Change Cluster, University of Technology Sydney, Sydney 2007, Australia 2 Department of Microbiology, Noakhali Science and Technology University, Chittagong 3814, Bangladesh 3 Finnish Environment Institute, Marine Research Centre, 00790 Helsinki, Finland * Correspondence:
[email protected] Received: 22 June 2019; Accepted: 27 July 2019; Published: 29 July 2019 Abstract: In marine ecosystems, dinoflagellates can become highly abundant and even dominant at times, despite their comparatively slow growth rates. One factor that may play a role in their ecological success is the production of complex secondary metabolite compounds that can have anti-predator, allelopathic, or other toxic effects on marine organisms, and also cause seafood poisoning in humans. Our knowledge about the genes involved in toxin biosynthesis in dinoflagellates is currently limited due to the complex genomic features of these organisms. Most recently, the sequencing of dinoflagellate transcriptomes has provided us with valuable insights into the biosynthesis of polyketide and alkaloid-based toxin molecules in dinoflagellate species. This review synthesizes the recent progress that has been made in understanding the evolution, biosynthetic pathways, and gene regulation in dinoflagellates with the aid of transcriptomic and other molecular genetic tools, and provides a pathway for future studies of dinoflagellates in this exciting omics era. Keywords: dinoflagellates; toxins; transcriptomics; polyketides; alkaloids 1. Introduction Marine microbial eukaryotes are a diverse group of organisms comprising lineages that differ widely in their evolutionary histories, ecological niches, growth requirements, and nutritional strategies [1–5].