Transcriptome analysis of zebra fish (Danio rerio) eggs following treatment with malachite green

Abstract

Malachite green is widely used in aquaculture as a parasiticide and in food, textile, and other industries for other purposes. Most previous studies have reported harmful effects as phenotypes; however, few studies have explored the mechanism of malachite green's toxicity. In the present study, the effect of malachite green on the eggs of the model fish zebra fish (Danio rerio) eggs were analyzed at the transcriptome level to study the toxicity mechanism of malachite green on aquatic organisms. Six normalized cDNA libraries were constructed using RNA from the control group and the malachite green treatment group. A total of 257,730,582 clean reads were obtained. In comparison with the reference genome, statistical analysis of the reads, unmapped reads, multimap reads, and the multimap read rate showed no significant differences (p > 0.05). However, the mapped read rate and unmapped read rate showed significant differences (p < 0.05) between the control and malachite green treatment groups, suggesting no difference in sample sequencing between the two groups, and that malachite green induced genetic toxicity in fish eggs. Further analysis identified 2436 significantly differentially expressed genes (DEGs) (including 1376 upregulated genes and 1060 downregulated genes) in zebra fish eggs following malachite green treatment. Gene ontology (GO) analysis revealed 103 terms belonging to biological processes, 12 terms belonging to cellular component, and 43 terms belonging to molecular function that were significantly enriched among the DEGs. Regulation of G-protein activated inward rectifier potassium channel activity and regulation of inward rectifier potassium channel activity were the most remarkably enriched biological processes. In Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis, DEGs were annotated to 322 known KEGG pathways. However, only one KEGG pathway, aminoacyl-tRNA biosynthesis, was enriched, and only significantly upregulated DEGs (tRNA ligase) was annotated in this pathway.