Full-Length Transcriptome Characterization and Comparative Analysis of Chosenia arbutifolia

As a unique tree species in the Salicaceae family, Chosenia arbutifolia is used primarily for construction materials and landscape planting in China. Compared with other Salicaceae species members, the genomic resources of C. arbutifolia are extremely scarce. Thus, in the present study, the full-length transcriptome of C. arbutifolia was sequenced by single-molecular real-time sequencing (SMRT) technology based on the PacBio platform. Then, it was compared against those of other Salicaceae species. We generated 17,397,064 subreads and 95,940 polished reads with an average length of 1812 bp, which were acquired through calibration, clustering, and polishing. In total, 50,073 genes were reconstructed, of which 48,174 open reading frames, 4281 long non-coding RNAs, and 3121 transcription factors were discovered. Functional annotation revealed that 47,717 genes had a hit in at least one of five reference databases. Moreover, a set of 12,332 putative SSR markers were screened among the reconstructed genes. Single-copy and special orthogroups, and divergent and conserved genes, were identified and analyzed to find divergence among C. arbutifolia and the five Salicaceae species. To reveal genes involved in a specific function and pathway, enrichment analyses for GO and KEGG were also performed. In conclusion, the present study empirically confirmed that SMRT sequencing realistically depicted the C. arbutifolia transcriptome and provided a comprehensive reference for functional genomic research on Salicaceae species.