Diversity and distribution of harmful microalgae in the Gulf of Thailand assessed by DNA metabarcoding

Fu, Zhengxu and Piumsomboon, Ajcharaporn and Punnarak, Porntep and Uttayarnmanee, Praderm and Leaw, Chui Pin and Lim, Po Teen and Wang, Aijun and Gu, Haifeng (2021) Diversity and distribution of harmful microalgae in the Gulf of Thailand assessed by DNA metabarcoding. Harmful Algae, 106. ISSN 1568-9883, DOI https://doi.org/10.1016/j.hal.2021.102063.

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Information on the diversity and distribution of harmful microalgae in the Gulf of Thailand is very limited and mainly based on microscopic observations. Here, we collected 44 water samples from the Gulf of Thailand and its adjacent water (Perhentian Island, Malaysia) for comparison in 2018. DNA metabarcoding was performed targeting the partial large subunit ribosomal RNA gene (LSU rDNA D1-D3) and the internal transcribed spacers (ITS1 and ITS2). A total of 50 dinoflagellate genera (made up of 72 species) were identified based on the LSU rDNA dataset, while the results of ITS1 and ITS2 datasets revealed 33 and 32 dinoflagellate genera comprising 69 and 64 species, respectively. Five potentially toxic Pseudo-nitzschia (Bacillariophyceae) species were detected, with four as newly recorded species in the water (Pseudo-nitzschia americana/brasilliana, Pseudo-nitzschia simulans/delicatissima, P. galaxiae and P. multistriata). The highest relative abundances of P. galaxiae and P. multistriata were found in Trat Bay and Chumphon (accounting for 0.20% and 0.06% of total ASVs abundance, respectively). Three paralytic shellfish toxin producing dinoflagellate species were detected: Alexandrium tamiyavanichii, Alexandrium fragae, and Gymnodinium catenatum. The highest abundance of A. tamiyavanichii was found in the surface sample of Chumphon (CHO7 station), accounting for 1.95% of total ASVs abundance. Two azaspiracid producing dinoflagellate species, Azadinium poporum ribotype B, Azadinium spinosum ribotype A, and a pinnatoxin producing dinoflagellate species Vulcanodinium rugosum, with two ribotypes B and C, were revealed from the datasets although with very low abundances. Six fish killing dinoflagellate species, including Margalefidinium polykrikoides group IV, Margalefidinium fulvescens, Karenia mikimotoi, Karenia selliformis ribotype B, Karlodinium australe, and Karlodinium digitatum were detected and all representing new records in this area. The findings of numerous harmful microalgal species in the Gulf of Thailand highlight the potential risk of human intoxication and fish killing events.

Item Type: Article
Funders: National Natural Science Foundation of China (NSFC) [Grant No: 42030404 & 41961144022], China-ASEAN Maritime Cooperation Fund Project
Uncontrolled Keywords: Alexandrium fragae; Azadinium spinosum; High-throughput sequencing; Fish killing; Paralytic shellfish poisoning
Subjects: G Geography. Anthropology. Recreation > GC Oceanography
G Geography. Anthropology. Recreation > GE Environmental Sciences
Divisions: Deputy Vice Chancellor (Research & Innovation) Office > Institute of Ocean and Earth Sciences
Depositing User: Ms Zaharah Ramly
Date Deposited: 13 Jul 2022 03:15
Last Modified: 13 Jul 2022 03:15
URI: http://eprints.um.edu.my/id/eprint/33919

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