Toxic effects of terpinolene on Microcystis aeruginosa: Physiological, metabolism, gene transcription, and growth effects

Bioherbicide terpinolene is widely employed in the agricultural field because of its unique phytotoxic properties. However, little is known about the toxicity of bioherbicide on harmful algal blooms (HABs) and its mechanisms. Therefore, in this study, the inhibiting effect of bioherbicide terpinolene on the growth and physiological change of Microcystis aeruginosa was determined. Results showed that the cell density and photosynthetic activity of microalgae were significantly inhibited by terpinolene. Activities of nitrate reductase (NR) and glutamine synthetase (GS) were decreased separately by 25.38% and 42.75% after 4 d of exposure to 1.47 mM terpinolene, suggesting the inhibiting effect of terpinolene on algal nitrogen metabolism. However, the transcript abundance of genes related to membrane protein cytochrome c oxidase subunit II (COX…