A Chromosome-level genome assembly of the striped catfish (Pangasianodon hypophthalmus) reveals molecular mechanisms for its high-fat trait

Striped catfish (Pangasianodon hypophthalmus), belonging to the Pangasiidae family, has become an economically important fish with wide cultivation in Southeast Asia. Owing to the high-fat trait, it is always considered as an oily fish. In our present study, a high-quality genome assembly of the striped catfish was generated by integration of short reads from an Illumina Hiseq Xten platform, long reads from a Nanopore platform, and Hi-C sequencing data. This assembled genome is 731.7 Mb in length, with a scaffold N50 of 29.5 Mb and anchoring on 30 chromosomes. A total 18,895 protein-coding genes were predicted, among them 98.46% were functionally annotated. Interestingly, we identified a tandem triplication of fatty acid binding protein 1 gene (fabp1; thereby named as fabp1-1, fabp1-2 and fabp1-3 respectively), which may be critical for molecular regulation of the high-fat trait in the striped catfish. Compared with Fabp1-1 (similar to the conserved Fabp1 in various vertebrate species), the R126T mutation may potentially affect the fatty acid binding capacity of the Fabp1 isotypes 2 and 3. In summary, we report a high-quality chromosome-level genome assembly of the striped catfish, which provides a valuable genetic resource for biomedical studies on the high-fat trait, and laying a foundation for practical aquaculture and molecular breeding of this international teleost species.