Barbel regeneration and function divergence in red-tail catfish (Hemibagrus wyckioides) based on the chromosome-level genomes and comparative transcriptomes.

Catfish (Siluriformes) are one of the most diverse vertebrate orders and are characterized by whisker-like barbels, which are important sensory organs in most of teleosts. However, their specific biological functions are still unclear. Red-tail catfish (Hemibagrus wyckioides) is well-known catfish species with four pairs of barbels, of which the maxillary barbels reach two-thirds of the body length. In this study, a 776.58 Mb high-quality chromosome-level genome was assembled into 29 chromosomes. Comparative genome data indicated that the barbeled regeneration gene ccl33 has expanded into 11 tandemly duplicated copies. Transcriptome data revealed the functional differentiation of different barbels and suggested that the maxillary barbel might be necessary for water temperature perception. Taste receptor genes were also characterized in teleosts with different food habits. Selection pressures were revealed to affect the sugar-based solute transport domain of the sweet taste receptor gene t1r2 in carnivorous fishes. In addition, the bitter taste receptor gene t2r200 was found to be lost from the genomes of four catfish species. Therefore, our study provides a genomic foundation for understanding the regeneration and functional differentiation of barbels in red-tail catfish and also reveals novel insights into the feeding evolution of fish species with different feeding habits. • A high-quality reference genome sequence with complete annotation in red-tail catfish was assembled in this study. • Genome evolution among the different catfish genomes was explored. • Barbeled regeneration gene ccl33 was found to be tandemly duplicated in red-tail catfish genome. • This research revealed functional differentiation of four pairs of barbels. • Two taste receptor genes t1r2 and t2r were characterized in different food habit teleosts. [ABSTRACT FROM AUTHOR]