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UTS C3 Climate Change Cluster

Anna Liza Kretzschmar

C3 PhD student Anna Kretzschmer

Title: Molecular genetics of Gambierdiscus, producer of ciguatera fish poisoning

Supervisor: Associate Professor Shauna Murray

Email: Anna.Kretzschmar@uts.edu.au

Background: Gambierdiscus is a genus of benthic dinoflagellates, found worldwide, and forms harmful algal blooms (HABs). Some species produce neurotoxins (maitotoxins (MTX) and ciguatoxins (CTX)) which  bioaccumulate and cause ciguatera fish poisoning (CFP). CFP is endemic to Australia and especially prevalent in coastal areas adjacent to the Great Barrier Reef; as well as in the Pacific Island nations. The habitat range of Gambierdiscus is predicted to extend with the advent of climate change which brings CFP into previously unaffected regions. The disease is incapacitating and poses a serious threat to local populations as well as the seafood industry.

The crux of the problem is that not all members of this genus produce these toxins and which do and which do not is not well established. Whether the production of these toxins is a feature unique to Gambierdiscus or if members of closely related genera produce these toxins is also not well established, and currently difficult to ascertain because the evolutionary history of the clade within which these organisms reside in is unclear. 

Furthermore, there are several unanswered questions the answers to which are essential for establishing a monitoring framework for regions at risk of CFP. For example: what genes are involved in toxin production? And what factors drive the expression of these genes and therefore production of these toxins? 

As CFP is increasing in frequency in the Pacific and in other regions, an understanding of the genetics and toxicology of these organisms is becoming increasingly important.

Project aims: to investigate toxigenic species of Gambierdiscus in CFP endemic regions, which brings us closer to finding and understanding the causative agent of CFP in Australia. This will be done by:

- Elucidating the diversity of Gambierdiscus at selected sites,
- Determining the evolution and phylogenetics of the clade of which Gambierdiscus is a part with a focus on toxigenic members,
- Investigate the genetics of toxin production in species of Gambierdiscus,
- Determine the ecological factors impacting differential expression of toxin related genes in Gambierdiscus.

Publications:
Kretzschmar, Anna Liza, and Manefield, Mike. "The role of lipids in activated sludge floc formation."  AIMS Environmental Science (2015).