Transcriptome analysis of 1- and 3-year-old Panax notoginseng roots and functional characterization of saponin biosynthetic genes DS and CYP716A47-like
Transcriptome analysis revealed high expression of saponin biosynthetic genes may account for highly accumulated saponins in 3-year-old Panax notoginseng roots and DS and CYP716A47 - like were functionally verified by transgenic tobacco.
Panax notoginseng is a well-known traditional medical herb that contains bioactive compounds known as saponins. Three major dammarene-type triterpene saponins including R1, Rb1, and Rg1 were found to be highly accumulated in the roots of 3-year-old plants when compared to those of 1-year-old plants. However, the underlying cellular mechanism is poorly understood. In this study, transcriptome analysis revealed that most genes involved in saponin biosynthesis in P. notoginseng roots augmented during their growth periods. The analysis of the KEGG pathway indicated that the primary metabolism, cell growth, and differentiation were less active in the roots of 3-year-old plant; however, secondary metabolisms were enhanced, thus providing molecular evidence for the harvesting of P. notoginseng roots in the 3rd year of growth. Furthermore, the functional role of DS and CYP716A47-like, two of the candidate genes involved in saponin biosynthesis isolated from P. notoginseng, were verified via overexpression in cultivated tobacco. Approximately, 0.325 µg g−1 of dammarenediol-II and 0.320 µg g−1 of protopanaxadiol were recorded in the dry leaves of transgenic tobacco overexpressed with DS and both DS and CYP716A47-like, respectively. This study provides insights into the molecular mechanisms for saponin accumulation in P. notoginseng roots during its growth period and paves a promising way to produce dammarenediol-II and protopanaxadiol via transgenic techniques.
Keywords1- and 3-year-old Panax notoginseng Dammarene-type triterpene saponins RNA-seq Transgenic tobacco
High-performance liquid chromatography
3-Hydroxy-3-methylglutaryl coenzyme-A synthase
Mevalonate diphosphate decarboxylase
Isopentenyl diphosphate isomerase
Geranylgeranyl pyrophosphate synthase
Farnesyl diphosphate synthase
Differentially expressed genes
We thank Biological Technology Open Platform of Kunming Institute of Botany, the Chinese Academy of Sciences for greenhouse services. This project is supported by the Major Science and Technique Programs in Yunnan Province (No. 2016ZF001), and 100-Oversea-Top-Talents Recruitment plan of Yunnan.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Chun JH, Adhikari PB, Park SB, Han JY, Choi YE (2015) Production of the dammarene sapogenin (protopanaxadiol) in transgenic tobacco plants and cultured cells by heterologous expression of PgDDS and CYP716A47. Plant Cell Rep 34(9):1551–1560. https://doi.org/10.1007/s00299-015-1806-9 CrossRefGoogle Scholar
- Haralampidis K, Trojanowska M, Osbourn AE (2002) Biosynthesis of triterpenoid saponins in plants. Adv Biochem Eng Biotechnol 75:31–49Google Scholar
- Jia XH, Wang CQ, Liu JH, Li XW, Wang X, Shang MY, Cai SQ, Zhu S, Komatsu K (2013) Comparative studies of saponins in 1-3-year-old main roots, fibrous roots, and rhizomes of Panax notoginseng, and identification of different parts and growth-year samples. J Nat Med 67(2):339–349. https://doi.org/10.1007/s11418-012-0691-6 CrossRefGoogle Scholar
- Li J, Wang J, Wu X, Liu D, Li J, Li J, Liu S, Gao W (2017) Jasmonic acid and methyl dihydrojasmonate enhance saponin biosynthesis as well as expression of functional genes in adventitious roots of Panax notoginseng F. H. Chen. Biotechnol Appl Biochem 64(2):225–238. https://doi.org/10.1002/bab.1477 CrossRefGoogle Scholar
- Liu MH, Yang BR, Cheung WF, Yang KY, Zhou HF, Kwok JS, Liu GC, Li XF, Zhong S, Lee SM, Tsui SK (2015) Transcriptome analysis of leaves, roots and flowers of Panax notoginseng identifies genes involved in ginsenoside and alkaloid biosynthesis. BMC Genom 16:265. https://doi.org/10.1186/s12864-015-1477-5 CrossRefGoogle Scholar
- Zhou J, Huang W, Wu M, Yang C, Feng G, Wu Z (1975) Triterpenoids from Panax Linn. and their relationship with taxonomy and geographical distribution. Acta Phytotaxon Sin 13(2):41Google Scholar