Glass catfish (Kryptopterus vitreolus) is commonly distributed in several Asian countries, such as Thailand, Malaysia, and Indonesia. It is renowned for its near-transparent appearance, which has drawn considerable attention for biomedical research and the tropical ornamental fish industry. Here, we successfully constructed the first telomere-to-telomere (T2T) chromosome-scale genome assembly for glass catfish, by integration of PacBio HiFi, Nanopore ONT ultra-long, and Hi-C sequencing technologies. The haplotypic assembly covers approximately 687.7 Mb in length, featuring a high contig N50 of 21.3 Mb. This assembly was then anchored into 32 chromosomes, presenting a complete set of 64 telomeres and 32 centromeres. It was predicted with 252.4 Mb of repetitive sequences and annotated with a total of 24,696 protein-coding genes. Subsequent BUSCO analysis revealed high genome completeness (up to 96.4%). This high-quality T2T genome assembly not only provides a valuable genetic resource for investigating the molecular mechanisms underlying transparency, but also supports in-depth studies on functional genomics, genetic diversity, and selective breeding for this economically important fish species.
Infectious bronchitis virus (IBV), an ongoing emergence enveloped virus with a single-stranded positive-sense RNA genome, belongs to the Gammacoronavirus genus in the Coronaviridae family. IBV-associated tracheitis, nephritis, salpingitis, proventriculitis and egg drop have caused devastating economic losses to poultry industry worldwide. Since the end of 2018, a remarkably increasing number of commercial broilers and layers, vaccinated or not, were infected with IBV in China. Here, we described two IB outbreaks with severe respiratory system or kidney injury in IBV-vaccinated commercial poultry farms in central China. Other possible causative viral pathogens, including avian influenza virus (AIV), Newcastle disease virus (NDV) and Kedah fatal kidney syndrome virus (KFKSV), were excluded by reverse transcription-polymerase chain reaction (RT-PCR), and three virulent IBV strains, HeN-1/China/2019, HeN-2/China/2019 and HeN-101/China/2019, were identified. Although the gross pathologic appearance of these two IB outbreaks was different, the newly identified IBV strains were all closely related to the ck/China/I0529/17 strain and grouped into GI-19 genotype clade based on the sequencing and phylogenetic analysis of the complete S1 genes. Moreover, there are still some evolutionary distance between the newly identified IBV strains, HeN-101/China/2019 in particular, and other GI-19 strains, suggesting that Chinese IBV strains constantly emerge and evolve towards different directions. In conclusion, this study provided an insight of the recently emerging IBV outbreaks in IBV-vaccinated commercial poultry farms and identified the genetic characteristics of three virulent GI-19 IBV strains, which shows the need to carry out proper preventive measures and control strategies.