A combined proteomics and metabolomics analysis reveals the invisible regulation of plant root responses to oxybenzone (benzophenone-3) stress

Oxybenzone, an environmental pollutant affecting both agriculture and aquatic ecological integrity, has been demonstrated to act as a physiological and metabolic inhibitor on plants, animals, and microorganisms. Research on oxybenzone in higher plants has focused on the above-ground anatomy (leaves), while research on the under-ground parts (roots) has been neglected. In this study, the changes in plant root protein expression and metabolic pathways under oxybenzone treatment were explored through a combined proteomics and metabolomics analysis. A total of 506 differential proteins and 96 differential metabolites were identified, which were mainly distributed in critical pathways such as those for carbon (C) and nitrogen (N) metabolism, lipid metabolism, and antioxidation. Bioinformatics analysis shows that oxybenzone toxicity is predominantly reflected in alterations to root respiratory homeostasis and the manifestation of damaging reactive oxygen species (ROS) and membrane lipid peroxidation, changes to disease resistance-associated proteins, changes to normal C-flow distribution, and the inhibition of cell absorption and utilization of N sources. Plants respond to oxybenzone stress mainly by reconfiguring the mitochondrial electron-transport-chain to bypass oxidative-damage components; improving the efficiency of the antioxidant system to remove excessively accumulated ROS; promoting the detoxification of harmful membrane lipid peroxides; increasing osmotic adjustment substance (such as proline and raffinose) accumulation; adjusting C flow distribution to produce more nicotinamide adenine dinucleotide phosphate (NADPH) for the glutathione cycle; and accumulating free amino acids to increase plant stress tolerant. Our results are the first to map the changes in the physiological and metabolic regulatory network of higher plant roots under oxybenzone stress.