Kohli, GS and John, U and Figueroa, RI and Rhodes, LL and Harwood, DT and Groth, M and Bolch, CJS and Murray, SA, Polyketide synthesis genes associated with toxin production in two species of Gambierdiscus (Dinophyceae), BMC Genomics, 16, (1) Article 410. ISSN 1471-2164 (2015) [Refereed Article]
© 2015 Kohli et al. Licensed under Creative Commons Attribution 4.0 International (CC BY 4) http://creativecommons.org/licenses/by/4.0/
Marine microbial protists, in particular, dinoflagellates, produce polyketide toxins with ecosystem-wide and human health impacts. Species of Gambierdiscus produce the polyether ladder compounds ciguatoxins and maitotoxins, which can lead to ciguatera fish poisoning, a serious human illness associated with reef fish consumption. Genes associated with the biosynthesis of polyether ladder compounds are yet to be elucidated, however, stable isotope feeding studies of such compounds consistently support their polyketide origin indicating that polyketide synthases are involved in their biosynthesis.
Here, we report the toxicity, genome size, gene content and transcriptome of Gambierdiscus australes and G. belizeanus. G. australes produced maitotoxin-1 and maitotoxin-3, while G. belizeanus produced maitotoxin-3, for which cell extracts were toxic to mice by IP injection (LD50 = 3.8 mg kg-1). The gene catalogues comprised 83,353 and 84,870 unique contigs, with genome sizes of 32.5 ± 3.7 Gbp and 35 ± 0.88 Gbp, respectively, and are amongst the most comprehensive yet reported from a dinoflagellate. We found three hundred and six genes involved in polyketide biosynthesis, including one hundred and ninty-two ketoacyl synthase transcripts, which formed five unique phylogenetic clusters.
Two clusters were unique to these maitotoxin-producing dinoflagellate species, suggesting that they may be associated with maitotoxin biosynthesis. This work represents a significant step forward in our understanding of the genetic basis of polyketide production in dinoflagellates, in particular, species responsible for ciguatera fish poisoning.
|Item Type:||Refereed Article|
|Keywords:||Gambierdiscus, ciguatera, ciguatoxin, maitotoxin, polyketide, synthesis gene|
|Research Division:||Biological Sciences|
|Research Group:||Plant Biology|
|Research Field:||Phycology (incl. Marine Grasses)|
|Objective Division:||Animal Production and Animal Primary Products|
|Objective Group:||Fisheries - Wild Caught|
|Objective Field:||Fisheries - Wild Caught not elsewhere classified|
|UTAS Author:||Bolch, CJS (Associate Professor Christopher Bolch)|
|Funding Support:||Australian Research Council (DP0880264)|
|Web of Science® Times Cited:||18|
|Deposited By:||IMAS Research and Education Centre|
|Downloads:||93 View Download Statistics|
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