Transcriptomic and gene-family dynamic analyses reveal gene expression pattern and evolution in toxin-producing tissues of Asiatic toad (Bufo gargarizans)

Comprising a major clade of Anura, toads produce and secrete numerous toxins from both the parotoid glands behind their eyes dorsal skin. These toxins, made various proteins compounds, possess pharmacological potential to be repurposed benefit human health. However, detailed genetic regulation toad toxin production is still poorly understood. A recent publication uncovering genome representative Asiatic ( Bufo gargarizans ) provides good reference resolve this issue. In present study, we sequenced transcriptomes gland, skin liver toad. Combining our data with 35 previously published across eight different tissues same species but locations, constructed comprehensive gene co-expression network assistance assembly. We identified 2,701 co-expressed genes in toxin-producing (including gland skin). By comparative genomic analysis, 599 expanded families 2,720 genes. Through overlapping these tissues, observed that three cytochrome P450 Cyp family members Cyp27a1 , Cyp2c29 Cyp2c39 were significantly enriched pathways related cholesterol metabolism. Cholesterol critical precursor steroids, known main steroidal bufadienolides are considered as bioactive components found 3-hydroxy-methylglutaryl CoA reductase hmgcr ), encoding rate-limiting enzyme for biosynthesis, appears multiple copies common toad, possibly originating tandem duplication event. The five consistently displayed higher transcription levels when compared abdominal skin, suggesting it vital candidate involvement production. Taken together, current study uncovers transcriptomic gene-family dynamic evidence reveal role expression changes toxins.