Supervisors: A/Prof. Shauna Murray, Dr. Gurjeet Kohli (Co-Supervisor)
Marine biotoxins are synthesised by dinoflagellates, a group of marine microalgae, and are associated with Harmful Algal Blooms (HABs) which have significant ecological and human health impacts worldwide. In Australian marine waters, Alexandrium minutum, Alexandrium fundyense, Gymnodinium catenatum and Alexandrium pacificum, are known to produce paralytic shellfish toxins that can cause Paralytic Shellfish Poisoning (PSP) in humans as a result of shellfish consumption.
Regular monitoring is one of the management strategies applied to minimise the damage caused by HABs. For this purpose, a reliable and sensitive assay is crucial. A qPCR-based genetic tool based on the genes involved in the saxitoxin biosynthesis pathway (STX) can detect and quantify STX biosynthesis genes in marine waters. This tool has been successfully used to detect and quantify blooms of Alexandrium spp. from France, Australia, China and the US.
Previous studies of the dinoflagellate genome imply that many genes have multiple copies in their genomes. This also includes the sxtA gene. Understanding the gene copy variation of STX biosynthesis genes are important in order to accurately determine the cell number in environmental samples.
The major aim of this project is to collect information about the inter-species and inter-strain variation of gene copy number in ribosomal and sxtA genes of STX-producing marine phytoplankton. The use of ribosomal and sxtA gene-based assays in environmental samples will also be validated in this study. Furthermore, the project will attempt to identify the link between gene copy number and toxin production.