Full-Length Hybrid Transcriptome of the Olfactory Rosette in Senegalese Sole (Solea senegalensis): An Essential Genomic Resource for Improving Reproduction on Farms.

Senegalese sole is a promising European aquaculture species whose main challenge is that captive-born males (F1) are unable to reproduce in farms, hindering breeding programs. Chemical communication through the olfactory system is hypothesized to stem this issue. Although significant advancement in genomic resources has been made recently, scarce information exists on the genomic basis of olfaction, a special sensory system for demersal species like flatfish, which could play a prominent role in reproduction, social and environmental interactions. A full-length transcriptome of the olfactory rosettes including females, males, juveniles and adults, of both F1 and wild origins, was generated at the isoform-level by combining Oxford Nanopore long-read and Illumina short-read sequencing. A total of 20,670 transcripts actively expressed were identified: 13,941 known transcripts, 5,758 novel transcripts from known genes, and 971 from novel genes. Given the important role of olfaction in reproductive behaviour, we comparatively examined the expression and functional enrichment of the olfactory receptor gene families (OlfC, OR, ORA and TAAR). Our comprehensive olfactory transcriptome of Senegalese sole provides a foundation for delving into the functional basis of this complex organ in teleost and flatfish. Furthermore, it provides a valuable resource for addressing reproductive management challenges in Senegalese sole aquaculture.