The snow trout (Schizothorax richardsonii) is endemic to the high altitudinal Himalayan region and thrive well in a wide thermal regime (0-27°C). The species can be used as a model species to study the abiotic and biotic stress response of cold-water fish species. In the present study, we compared the liver transcriptomes of Aeromonas hydrophilla challenged (Ah+) and mock challenged (Ar-) S. richardsonii. The transcriptome database for the species has been developed with a cascade of immune-related differentially expressed genes using RNA sequencing (2×100 bp paired-end) carried out on the Illumina 2000 sequencing platform. Among 50,453 unigenes obtained from de novo assembly, 24,464 unigenes were annotated, among which 82 unigenes were associated with immune responses genes. There were 265 differentially expressed unigenes (189 upregulated, and 75 down-regulated) in Ah+ compared to Ahgroup. The majority of genes involved in immune regulation during bacterial pathogenesis are linked to extracellular region, membrane integrity, ion binding, signal transduction, antigen processing and presentation, MHC class I protein complex, etc. Particularly, 15 unigenes associated with immune response and 9 unigenes related to signal transduction gene ontology terms were significantly dysregulated in the bacterial challenged group. Four immune genes Interleukin 1β1, prostaglandin-endoperoxide synthase 2a & 2b, and ankyrin repeat domain were found to be very active against A. hydrophilla. The present study provides preliminary insight into possible changes at the molecular level of this potential model fish during a pathogenic infestation.
Published Date: 2021-09-13;