Interactive effects of warming and copper toxicity on a tropical freshwater green microalgaChloromonas augustae(Chlorophyceae)

Yong, Wai-Kuan and Sim, Kae Shin and Poong, Sze-Wan and Wei, Dong and Phang, Siew-Moi and Lim, Phaik Eem (2021) Interactive effects of warming and copper toxicity on a tropical freshwater green microalgaChloromonas augustae(Chlorophyceae). Journal of Applied Phycology, 33 (1, SI). pp. 67-77. ISSN 0921-8971, DOI

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Microalgae, the primary producers in aquatic ecosystems, are highly susceptible to heavy metal contamination. In this study, the interactive effects of warming and copper (Cu) toxicity on the physiology (cell density, photosynthetic efficiency, reactive oxygen species (ROS) production, and metal uptake in the biomass) and biochemistry (metabolite) of a freshwater green microalga,Chloromonas augustae(UMACC246), were elucidated. The microalgae were exposed to culture media supplemented with copper (II) sulfate pentahydrate (CuSO4 center dot 5H(2)O) at different concentrations (50, 150, 250 mu M) at two temperatures, 25 degrees C (control) and 30 degrees C (sub-optimal), for 24 h. The results indicated thatC.augustaeexhibited a concentration- and temperature-dependent decrease in the cell density. Copper greatly affected the photosynthetic efficiency ofC.augustaeby reducing the maximum rate of relative electron transport (rETR(m)), light harvesting efficiency (alpha), and saturation irradiance (E-k). Warming increased ROS production remarkably in the microalga. Untargeted metabolomics indicated that temperature contributed to the most significant variations in the cultures (p < 0.05) in comparison with Cu toxicity or both factors combined. Compounds such as amino acids and amines were significantly dysregulated in response to warming and Cu toxicity. Pathway analyses showed that the glutathione metabolism, sulfur metabolism, and mechanisms in the amino acid metabolism were regulated, suggesting that the microalga underwent primary metabolism restructuring for survival and adaptation. Overall, the data showed that warming enhanced Cu toxicity in the cultures. This implied that increasing water temperature and metal toxicity due to global warming and anthropogenic activities will probably exacerbate existing threats to the primary producers.

Item Type: Article
Funders: Ministry of Education's HICOE grant (IOES-2014H), University of Malaya Research University Grant (TU001C-2018), Fundamental Research Grant Scheme (FP048-2016), University of Malaya PPP Grant (PG267-2016A), UMTop 100 University (TOP100PDIOES) fund by the University of Malaya
Uncontrolled Keywords: Chloromonas; Chlorophyceae; Copper toxicity; Metabolomics; Microalgae; Photosynthesis; Temperature stress
Subjects: Q Science > QH Natural history > QH301 Biology
Q Science > QR Microbiology
T Technology > T Technology (General)
Divisions: Faculty of Science > Institute of Biological Sciences
Institute of Advanced Studies
Deputy Vice Chancellor (Research & Innovation) Office > Institute of Ocean and Earth Sciences
Depositing User: Ms Zaharah Ramly
Date Deposited: 11 Aug 2022 01:19
Last Modified: 11 Aug 2022 01:19

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