Molecular detection and distribution of the genera Amphidoma and Azadinium (Amphidomataceae, Dinophyceae) in the coastal waters of Aotearoa/New Zealand

ABSTRACT

Molecular-based approaches for harmful algal bloom species, which can be difficult to identify by light microscopy, are important tools for detecting and predicting the blooms. In this study, 84 samples from Aotearoa/New Zealand coastal waters that contained Azadinium-like cells were analysed using an Amphidomataceae real-time PCR assay. Nineteen samples were positive, and 24 Azadinium-like clonal isolates were established from these samples. Subsequently, only five isolates from one sampling point were positive using the real-time PCR assay. Four of the five isolates were genetically identified as Amphidoma languida and one as Azadinium dalianense. The field samples were analysed retrospectively using the species-specific real-time PCR assays; Am. languida was detected from the temperate areas, while Az. poporum and Az. spinosum were detected at one site. Two representative strains of each species were analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), including Am. languida, which is known as toxic in the previous studies, but neither produced the currently monitored azaspiracids (AZAs). These two newly recorded species for New Zealand are important findings. The results highlight the need for more information on the spatio-temporal variations of potentially toxic Amphidomataceae species and the risk of AZAs in New Zealand coastal waters.

KEYWORDS:

• Azaspiracids
• azaspiracid shellfish poisoning
• dinoflagellates
• amphidomataceae
• harmful algae

Acknowledgements

We are grateful to the New Zealand Ministry of Primary Industries for allowing the use of samples for research purposes.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The research was funded by the New Zealand Ministry for Business, Innovation and Employment (Seafood Safety Platform, Contract No. CAWX1801; National Databases Contract No. CAWX0902). M. Balci was supported by the Scientific and Technological Research Council of Turkey (Turkey), International Postdoctoral Research Fellowship (Grant no: 1059B191800400) during the present study at the Cawthron Institute. T. Nishimura was supported by the Japan Society for the Promotion of Science Overseas Research Fellowship.