Whole-genome, transcriptome, and methylome analyses provide insights into the evolution of platycoside biosynthesis in Platycodon grandiflorus, a medicinal plant

Abstract

Triterpenoid saponins (TSs) are common plant defense phytochemicals with potential pharmaceutical properties. Platycodon grandiflorus (Campanulaceae) has been traditionally used to treat bronchitis and asthma in East Asia. The oleanane-type TSs, platycosides, are a major component of the P. grandiflorus root extract. Recent studies show that platycosides exhibit anti-inflammatory, antiobesity, anticancer, antiviral, and antiallergy properties. However, the evolutionary history of platycoside biosynthesis genes remains unknown. In this study, we sequenced the genome of P. grandiflorus and investigated the genes involved in platycoside biosynthesis. The draft genome of P. grandiflorus is 680.1 Mb long and contains 40,017 protein-coding genes. Genomic analysis revealed that the CYP716 family genes play a major role in platycoside oxidation. The CYP716 gene family of P. grandiflorus was much larger than that of other Asterid species. Orthologous gene annotation also revealed the expansion of β-amyrin synthases (bASs) in P. grandiflorus, which was confirmed by tissue-specific gene expression. In these expanded gene families, we identified key genes showing preferential expression in roots and association with platycoside biosynthesis. In addition, wholegenome bisulfite sequencing showed that CYP716 and bAS genes are hypomethylated in P. grandiflorus, suggesting that epigenetic modification of these two gene families affects platycoside biosynthesis. Thus whole-genome, transcriptome, and methylome data of P. grandiflorus provide novel insights into the regulation of platycoside biosynthesis by CYP716 and bAS gene families.

Identification and Functional Characterization of FLOWERING LOCUS T in Platycodon grandiflorus

“…grandiflorus , an FT-like gene was identified in the P . grandiflorus genome data [ 24 ] using the sequences of FTs from various species and was cloned for functional characterization. The PlgFT gene was found to have an open reading frame of 555 bp with a stop codon, encoding a protein of 184 amino acids ( Figure 1 ).…”

Developmental Methylome of the Medicinal Plant Catharanthus roseus Unravels the Tissue-Specific Control of the Monoterpene Indole Alkaloid Pathway by DNA Methylation

“…In comparison with the hypomethylated state of flavonoid biosynthetic genes increasing both their expression and anthocyanin accumulation in apple fruit skin [ 33 ], methylation of MIA genes may appear as limited. A recent study has reported an inverse correlation between a P450 encoding gene methylation level and its expression [ 67 ]. Expression was induced upon Jasmonic Acid elicitation in seedlings of Platycodon grandiflorus and related to a higher accumulation of the triterpenoid saponin platycoside.…”

Machine learning, transcriptome, and genotyping chip analyses provide insights into SNP markers identifying flower color in Platycodon grandiflorus

“…The reference genome for P. grandifloras was obtained from the P. grandiflorus genome project 1 ( http://platycodon.theragenetex.com/ ). The gene model and other functional annotations were also obtained from the respective site.…”

“…The bellflower ( Platycodon grandiflorus ) is a popular plant used as food, medicine, and ornamental plant in Asia 1 . P. grandiflorus is a monotypic species of the bellflower family (Campanulaceae).…”