Molecular mechanisms of benzophenone-induced toxicity in marine diatoms: Insights from Chaetoceros neogracilis

Benzophenones (BPs) are extensively utilized as ultraviolet filters in personal care products, and their increasing detection in aquatic environments has raised concerns regarding their role as environmental pollutants. Diatoms, a major group of phytoplankton, are frequently exposed to BPs through wastewater discharge and coastal recreational activities. Different BPs exhibit varying toxicities to marine phytoplankton, yet comparative studies examining their effects on the diatom at both physiological and molecular levels remain limited. This study investigated the molecular mechanisms by the 72 h acute toxicity test of marine diatom Chaetoceros neogracilis to three BPs—benzophenone-3 (BP-3), benzophenone-1 (BP-1), and benzophenone-8 (BP-8). The results demonstrated that BP-3 was the most toxic compound, followed by BP-8 and BP-1, with differentially expressed genes (DEGs) at EC₅₀ (0.36 ± 0.02 mg/L, 0.78 ± 0.05 mg/L and 4.03 ± 0.19 mg/L) concentrations being 2271, 734 and 1400, respectively. The primary pathways affected by BPs involved ribosomal pathways, photosynthesis, and photosynthetic antenna protein pathways. Notably, BP-3 uniquely disrupted the carbon fixation, plant hormone signaling and protein processing pathway, while BP-1 influenced amino acid metabolism and DNA mismatch repair. These findings provide novel insights into the ecotoxicity of BPs in marine microalgae, clarify the molecular mechanisms of detoxification, and offer potential strategies for environmental remediation.