Study on the Spatio-temporal Expression Pattern and Their Correlation of Monoterpene Glycosides Content and the Biosynthesis-related Gene in Paeonia Lactiflora Pall.

OBJECTIVE To study the expression pattern of monoterpene glycosides contents and their biosynthesis-related genes in different tissues of Paeonia lactiflora Pall. at different developmental stages, investigate the correlation between them.METHODS The content of oxypaeoniflorin, albiflorin, paeoniflorin and benzoylpaeoniflorin in root, leaf, flower, fruit and different tissues(phloem, xylem, fibril and velamen) of the root was determined by HPLC. RT-PCR was used to analyze the candidate genes related to biosynthesis of monoterpene glycosides. The correlation between the contents of four monoterpene glycosides and the expression levels of biosynthesis related genes was comprehensively analyzed by R language. RESULTS Paeoniflorin and benzoylpaeoniflorin were mainly distributed in roots, while oxypaeoniflorin and albiflorin were mainly distributed in flowers. Oxypaeoniflorin, paeoniflorin and benzoylpaeoniflorin were mainly distributed in xylem, while albiflorin was mainly distributed in phloem and fibrous roots. The contents of the four monoterpene glycosides in root were low in flowering and fruit stage, and the highest in withered stage, followed by leaf spreading stage. The correlation analysis between monoterpene glycosides content and the expression level of key enzyme genes showed that HMGR2 and IDI genes were closely positively correlated with the contents of paeoniflorin, benzoylpaeoniflorin and paeoniflorin. CONCLUSION Monoterpene glycosides and their biosynthesis related genes in P. lactflora showed spatio-temporal expression patterns, and mevalonate pathway is the main pathway for biosynthesis of terpenoid skeleton in P. lactiflora.