Transcriptome Analysis of Soiny Mullet Larvae Challenge with Polystyrene Microplastics

Microplastics (MPs) pollution has become a worldwide environmental problem. The study about the effects of microplastics on fish, especially on the fish immune system is limited. In the present study, the transcriptome of soiny mullet (Liza haematocheila) larvae at 7 d and 14 d post 0.5 mu m MPs exposure were analyzed by DNBSEQ platform. A total number of 96585 unigenes were obtained with average length of 1925 bp. Approximately 72.48% (70004), 76.80% (74176), and 62.94% (60787) unigenes were matched with the annotated sequences for non-redundant (NR), NCBI nucleotide (NT) and Swissprot database, respectively. Compared with control group, 1336 differently expressed genes (DEGs) were identified at 7 d post MPs exposure. As the MPs exposure time extended to 14 d, the number of DEGs in the MPs exposure group reached to 3561. Further, KEGG enrichment analysis revealed that several immune-related pathways, such as interleukin (IL)-17 signaling pathway, tumor necrosis factor (TNF) signaling pathway, were affected by MPs exposure. In addition, apoptosis signaling pathway was also enriched under MPs exposure. These results demonstrated that MPs can alter the expressions of immune-related genes, providing basis for understanding the immune toxicity of MPs on fish and other vertebrates.