Circular RNA profiling uncovers regulators of early body color transition in juvenile leopard coral grouper (Plectropomus leopardus)

BACKGROUND: The leopard coral grouper is a valued aquaculture species whose market value is influenced by its body color. Current research on its coloration focuses on adults, leaving early developmental mechanisms unclear. Circular RNAs are important regulators in various processes, including pigmentation. This study aimed to explore the role of circRNAs in early color formation of leopard coral grouper. RESULTS: Using skin tissues from transparent (26 dph) and newly pigmented red (30 dph) juveniles, we identified 42 differentially expressed circRNAs. Their source genes were enriched in pathways like Hedgehog signaling, cAMP signaling, and carotenoid metabolism. Four key circRNAs were identified, and a circRNA-miRNA network analysis suggested their involvement in melanin synthesis, pigment cell development, and carotenoid metabolism. The qPCR verification results were consistent with the trends in the sequencing results. CONCLUSIONS: This study provides the first circRNA profile during early color transition in leopard coral grouper, revealing a potential post-transcriptional regulatory network. The findings offer new insights into pigmentation mechanisms and provide valuable candidates for molecular-assisted breeding of color traits.