Comparative Transcriptomic Analysis on White and Blue Flowers of Platycodon grandiflorus to Elucidate Genes Involved in the Biosynthesis of Anthocyanins.

BACKGROUND

has long been used in Northeast Asia as a food and folk medicine to treat various diseases. The intense blue color of corolla is its characteristic feature.

OBJECTIVES

By comparing deep transcriptomic data of and its white cultivar, we intended to elucidate the molecular mechanisms concerning the biosynthesis of anthocyanins in this plant.

MATERIAL AND METHODS

We sampled blue mature flowers (PgB) and yellow young buds (PgY) of . Meanwhile, mature flowers (PgW) of white cultivar were also collected for RNA extraction and next-generation sequencing. After high-throughput sequencing, Trinity software was applied for de novo assembly and the resultant 49934 unigenes were subjected for expression analysis and annotation against NR, KEGG, UniProt, and Pfam databases.

RESULTS

In all, 32.77 Gb raw data were generated and the gene expression profile for the flowers of was constructed. Pathway enrichment analysis demonstrated that genes involved in flavone and flavonol biosynthesis were differently expressed.

CONCLUSIONS

The extremely low expression of flavonoid-3',5'-hydroxylase in PgY and PgW was regarded as the reason for the formation of its white cultivar. Our findings provided useful information for further studies into the biosynthetic mechanism of anthocyanins.