Transcriptome sequencing and analysis of sweet osmanthus (Osmanthus fragrans Lour.)

Abstract

Osmanthus fragrans is a woody, evergreen species of shrubs and small trees that is extensively planted in sub-tropical and temperate climates as an ornamental plant in gardens and for its health benefits. The flower color ranges from ivory to orange to pink among different varieties and even color difference during the whole blossom in the sweet osmanthus. Sweet osmanthus is widely cultivated throughout China and other countries due to its prominent fragrance, colorful flowers, and medicinal properties. However, the scanty genomic resources in the Olea family have greatly hindered further exploration of its genetic mechanism on these economically important traits. In this study, transcriptome sequencing of O. fragrans was performed using the Illumina HighSeqTM2000 sequencing platform. Next generation sequencing (NGS) of the transcriptome of O. fragrans produced 31.7G of clean bases (211,266,818 clean reads) that were assembled into 256,774 transcripts and 117,595 unigenes. Of them, 197 and 237 candidate genes involved in fragrance and pigment biosynthesis respectively were identified based on function annotation. Meanwhile, 1 unnamed protein and 468 functional unknown genes were also identified. Furthermore, mRNA sequencing expression profiling of O. fragrans were compared to previous genes’. In summary, this comprehensive transcriptome dataset allows the identification of genes associated with several major metabolic pathways and provides a useful public information platform for further functional genomic studiesin O. fragrans Lour.