Genome-Wide Identification of the Transient Receptor Potential Channel Family in Nile Tilapia and Expression Analysis in Response to Cold Stress

Transient receptor potential (TRP) channels play critical roles in animals in sensing diverse stimuli, especially environmental temperature. The teleost fish Nile tilapia (<i>Oreochromis niloticus</i>) cannot tolerate cold temperatures. In this study, we identified a total of 32 <i>TRP</i> genes in the tilapia genome. Based on analyses of gene structure and phylogenetic relationship, all tilapia <i>TRP</i> genes could be classified into six subfamilies, namely, TRPA, TRPC, TRPM, TRPV, TRPP, and TRPML. Comparative analysis showed that three <i>TRP</i> subfamilies-TRPC, TRPM, and TRPML-underwent an expansion in tilapia and other teleost fishes following three or four rounds of whole-genome duplication. In addition, expression profiling revealed that a large number of <i>TRP</i> genes were expressed in at least one tissue in adult tilapia. Notably, compared with normal growth temperature (28 °C), cold stress (10 °C) altered the expression of several <i>TRPs</i> in multiple tissues in adult tilapia, especially upregulating <i>TRPC5</i> in the brain and <i>TRPM7</i> in the gill. Collectively, these findings provide new insight into the phylogeny of <i>TRP</i> genes in animals and lay the foundation for further investigation into the roles of TRP channels in cold sensitivity in tilapia.