Full-length transcriptome annotation of a pyrosome, Pyrosoma atlanticum (Chordata, Thaliacea)

Abstract Pyrosomes represent a group of marine holozooplankton. They do not exist as individual entities but as intricate colonies comprising numerous zooids, well-known for their bioluminescent properties. Pyrosomes inhabit most oceanic waters spanning tropical to temperate regions. They serve as significant consumers of phytoplankton, playing a crucial role in transport of organic carbon and sedimentation of organic matter debris. Nonetheless, the knowledge about this group remains limited, particularly concerning genomic and gene aspects. To further investigate the pyrosome at the molecular level, we used Pyrosoma atlanticum, which is the best known of pyrosome, for investigation in this study. We performed PacBio Iso-Seq and Illumina RNA-seq to generate high-quality and full-length transcript data from P. atlanticum. The systematic gene functional annotation was performed by integrated data. The full-length transcriptome produced in this study represents the inaugural dataset of transcriptome within the class Thaliacea, serving as a reference for future investigations. Additionally, as a stem group for chordates, the information of pyrosomes can provide a valuable research foundation for the evolution of vertebrates.