Comparative Transcripto me Analysis Depicts Candidate Genes Involved in Skin Color Differentiation in Red Tilapia

Abstract

Background This study aimed to investigate the genetic molecular mechanism of body color differentiation and variation of red tilapia, selecting the main genes related to the variation and cultivating the pure and stable red tilapia variety. Results The effects of different temperature treatments on body color and survival of Guam red tilapia, pearl white red tilapia and Florida red tilapia were compared. Besides, comparative transcriptome analysis was used to screen the candidate genes linked to the skin color differentiation of pearl white red tilapia. Among them, the body color of Guam red tilapia changed when the water temperature dropped to 16 − 14 °C, and continued to drop to about 11 °C, it was discolored in a large area reaching above 90%. According to the differential analysis: Tyrosine Kinase STYK1, HSP70, HSP30 and Transcription factor Sp6 expressions were significantly increased in the low temperature group, while MC1R, Transcription factor (MafB, jun-D, AP-1, E2F5, ETV6, Sp9, Sp7, E2F1, Sp4) expressions were notably decreased. Conclusions In this study, the expressive quantity of tyrosine protein kinase in the low temperature group HLF7 was significantly higher than that in the normal temperature group HLF3, which indicated that the melanin synthesis ability was enhanced in the low temperature group HLF7. The result was consistent with the tendency of red tilapia to become darker as the temperature gradient decreased.