Effects of different Zn 2+ levels on antioxidant activity, fatty acid compositions, and related gene expressions in Phaeodactylum tricornutum

Ning Ma ^*

• Ludong University, Yantai, China

The present study was undertaken to examine the impact of varying concentrations of Zn 2+ on the growth, antioxidant levels, fatty acid composition, and related gene expression in a pennate diatom, Phaeodactylum tricornutum. As a prevalent environment contaminant, zinc is introduced into aquatic ecosystems via agricultural and industrial processes, exerting toxic effects on aquatic biota. This study determined that appropriate concentrations of Zn 2+ were essential for the growth of P.tricornutum, but high concentrations of Zn 2+ (1000.23 μM) significantly inhibited its growth. Zinc stress also led to the production of reactive oxygen species (ROS), which in turn triggered oxidative stress, as evidenced by changes in antioxidant enzyme activities and lipid peroxidation levels.Furthermore, zinc stress affected the fatty acid composition of P. tricornutum, particularly in the group exposed to high concentrations of Zn 2+ . There was a notable reduction in the levels of polyunsaturated fatty acids (PUFAs) and highly unsaturated fatty acids (HUFAs), while the levels of saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) increased. Gene expression analyses indicated alterations in the expression of zinc transporter proteins and antioxidant-related genes, suggesting that P. tricornutum adapts to zinc stress through the regulation of gene expression.These findings provide new insights into the understanding of the physiological and molecular responses of microalgae to zinc pollution and a scientific basis for evaluating the potential impacts of zinc pollution on aquatic ecosystems and developing bioremediation strategies.