Single-molecule real-time transcript sequencing facilitates transcriptome research in Pyropia hatainensis

Pyropia haitanensis is a high-yield commercial seaweed in China. P. haitanensis farms often suffer from many problems, such as severe germplasm degeneration, while the mechanisms underlying resistance to abiotic stresses remain unknown. Although many previous studies focused on using next-generation sequencing (NGS) technologies, the short-read sequences generated by NGS generally prevent the assembly of full-length transcripts. In the present study, which was based on hybrid sequencing (NGS and single-molecular real-time sequencing) of the P. haitanensis thallus transcriptome, we obtained high-quality full-length transcripts with a mean length of 2,998 bp and an N50 value of 3,366 bp. A total of 14,773 unigenes (93.52%) were annotated in at least one database, while approximately 60% of all unigenes were assembled by short Illumina reads. Moreover, we herein suggested that the genes involved in the biosynthesis of polyunsaturated fatty acids and heat shock proteins play an important role in the process of development and resistance to abiotic stresses in P. haitanensis. The present study, together with previously published ones, may facilitate seaweed transcriptome research.