Genome-wide comparative analysis between Cranoglanis bouderius and Pangasianodon hypophthalmus: Reveal the genes related to resistance to low-temperature stress

Previous studies have indicated that Cranoglanis bouderius and Pangasianodon hypophthalmus clustered into a sister group. However, there was a significant difference in their minimum tolerated temperatures. To reveal the temperature adaptation-related genes, a genome-wide comparative analysis was performed. First, a chromosome-level draft genome of C. bouderius was constructed in this study. The genome assembly was 999.18 Mb in size with a contig N50 of 20.47 Mb. Then, an additional 118.98 Gb of Hi-C data was applied to assemble contigs into scaffolds and 910.59 Mb was anchored and orientated onto 38 chromosomes of C. bouderius. A total of 24,165 protein-coding genes were predicted from the genome with 22,920 (94.84%) genes functionally annotated. Genome-wide comparative analysis revealed that the genes related to resistance to low-temperature stress were mainly enriched into the gene ontology (GO) terms associated with mitochondrial fusion and calcium ion transport. Further, the low-temperature stress test on the C. bouderius and P. hypophthalmus also revealed that the C. bouderius can better control the homeostasis of calcium ions in cells than P. hypophthalmus, and then better maintain the dynamic changes of mitochondrial fusion and fission in cells, thereby resisting cell damage caused by low-temperature stress.