Identification and In-Silico Characterization of Selected Osmoregulatory and Stress-Tolerance Genes of the Hilsa Shad (Tenualosa ilisha)

Osmoregulatory and stress-signaling genes are critical for fish survival and adaptation in dynamic aquatic environments. The Hilsa shad (Tenualosa ilisha), a migratory species of high economic and ecological importance, requires a thorough understanding of the molecular mechanisms underlying osmoregulation and stress signaling for effective management and sustainable production. In this study, we identified and characterized these genes using the draft genome of Hilsa. The identification process was based on the presence of corresponding functional domains, and gene characteristics such as coding sequence and protein length were calculated. Additionally, parameters like molecular weight (MW), isoelectric point (Ip), gene localization, gene structure, conserved motifs, and secondary/tertiary structures were analyzed, along with Gene Ontology (GO) analysis. The predicted genes were validated through PCR (Polymerase Chain Reaction) using gene-specific primers and sequencing. Sequence data confirmed the predicted genes, and blast analysis revealed high similarity with homologous genes from other fish species in the databases. Compared to other fish species, MW, Ip, gene structure, and conserved motifs exhibited notable diversity. Most of the identified genes were localized and expressed in the plasma membrane, nucleus, and cytoplasm. Secondary and 3D structural analyses showed a predominance of alpha helices with high-quality structure. GO analysis indicated that the majority of the genes are involved in ion transport, while others play roles in signal transduction, protein folding, and osteoclast differentiation. These findings provide valuable insights into the molecular functions of osmoregulatory and stress-signaling genes in Hilsa, which will contribute to a deeper understanding of their roles in osmoregulation