Gill and liver transcriptomic responses of Achirus lineatus (Neopterygii:Achiridae) exposed to water accommodated fraction (WAF) of light crude oil reveal an onset of hypoxia-like condition

Crude oil spills in aquatic ecosystems have long term impact on native biota. The objective of this study was to compare the transcriptomic changes in liver and gill of a marine fish species exposed to a sublethal acute concentration of water accommodated fraction (WAF) of light crude oil. Adult lined sole fish (Achirus lineatus) were exposed to WAF for 48 h. RNA-Seq was performed to assess the transcriptional changes in both organs. A total of 1073 differentially expressed genes (DEGs) were detected in gills; 662 (61.69%) were up-regulated and 411 (38.30%) were down-regulated whereas in liver, 515 DGEs; 306 (59.42%) were up-regulated, and 209 (40.58%) were down-regulated. Xenobiotic and redox metabolism along with DNA repair mechanisms were activated. The induction of hypoxia-regulated genes and generalized regulation of multiple signaling pathways support the hypothesis that WAF exposition causes a hypoxia-like condition. Our data provide insights into the mechanisms of WAF-induced toxicity in fish that would be useful to develop biomarkers for crude oil biomonitoring.