Time- and temperature-dependent molecular responses to UV-filter 2-ethylhexyl salicylate revealed by dose-dependent...

2-Ethylhexyl salicylate (EHS) is a widely used UV filter detected in multiple environmental compartments, yet its toxicological mechanisms remain poorly understood, particularly under varying environmental conditions. Here, we applied a dose-dependent yeast functional genomics approach (DYFGA) using a library of approximately 6000 Saccharomyces cerevisiae knockout strains to assess EHS toxicity across seven concentrations (0.02-20,000 μg/L) at three temperatures (23°C, 30°C, 37°C, representing low, optimal, and high-temperature stress, respectively) and two exposure durations (8 h, 24 h). We derived gene-level and pathway-level points of departure (PODs) to identify early molecular responses. EHS showed the strongest biological potency at 24 h, 30°C, followed by 8 h, 37°C. DNA replication and repair pathways ranked among the most sensitive pathways across most conditions, while lipid metabolism predominated at 30°C. YKL045W (involved in DNA replication and repair) and YPL028W (involved in lipid metabolism) exhibited the lowest average EC₅₀ values among genes in corresponding pathways. Cytotoxicity validation in single-gene knockout strains confirmed that YKL045W deletion significantly increased EHS sensitivity compared to wild-type (WT) yeast, whereas YPL028W deletion showed modest effects only at 8 h, 30°C. No significant differences occurred at 8 h, 23°C, indicating that low temperature reduces EHS toxicity. These findings indicate that DNA replication and repair pathway represents the primary early response involved in EHS toxicity, whereas lipid metabolism acts as a secondary pathway under optimal growth conditions. These findings interpret the early molecular responses induced by EHS toxicity under varying conditions, informing risk assessment in the context of climate warming, and provide a reference strategy for studying other chemical contaminants. It should be noted, however, that this study primarily serves to elucidate temperature-dependent molecular responses in the yeast model, and caution is required when extrapolating these results to natural ecosystems.