Single-cell RNA sequencing of zebrafish olfactory epithelium reveals cellular heterogeneity and responses to a conspecific alarm substance

Olfaction, the sense of smell, is vital for the survival of many species and serves as an excellent system for investigating the molecular basis of behavior. Fishes possess a well-developed olfactory system that governs various behaviors related to feeding, reproduction, and fear. However, the cellular diversity and heterogeneity of the fish olfactory epithelium remains largely unexplored. This study presents a single-cell atlas of the zebrafish olfactory epithelium using single-cell RNA sequencing (scRNA-seq). Through scRNA-seq analysis of approximately 10,587 ​cells, we identified nine distinct cell types with unique transcriptional profiles, including immature and mature olfactory sensory neurons (OSNs), horizontal basal cells, globose basal cells, and sustentacular cells, as well as lymphocyte and myeloid cells expressing immune signals. Further subcluster analysis revealed selective and combinatorial expression of key components in odorant-mediated signal transduction by distinct OSN populations. Additionally, we discovered transcriptional changes specific to certain OSN populations following exposure to a conspecific alarm substance. The single-cell transcriptional atlas of the zebrafish olfactory epithelium provided in this study serves as a valuable tool for exploring cell diversity and assessing genetic profiles from functional and behavioral perspectives in fish.