Ginsenosides in Panax genus and their biosynthesis

Abstract

Ginsenosides are a series of glycosylated triterpenoids which belong to protopanaxadiol (PPD)-, protopanaxatriol (PPT)-, ocotillol (OCT)- and oleanane (OA)-type saponins known as active compounds of Panax genus. They are accumulated in plant roots, stems, leaves, and flowers. The content and composition of ginsenosides are varied in different ginseng species, and in different parts of a certain plant. In this review, we summarized the representative saponins structures, their distributions and the contents in nearly 20 Panax species, and updated the biosynthetic pathways of ginsenosides focusing on enzymes responsible for structural diversified ginsenoside biosynthesis. We also emphasized the transcription factors in ginsenoside biosynthesis and non-coding RNAs in the growth of Panax genus plants, and highlighted the current three major biotechnological applications for ginsenosides production. This review covered advances in the past four decades, providing more clues for chemical discrimination and assessment on certain ginseng plants, new perspectives for rational evaluation and utilization of ginseng resource, and potential strategies for production of specific ginsenosides.

Keywords: ABA, abscisic acid; ADP, adenosine diphosphate; AtCPR (ATR), Arabidopsis thaliana cytochrome P450 reductase; BARS, baruol synthase; Biosynthetic pathway; Biotechnological approach; CAS, cycloartenol synthase; CDP, cytidine diphosphate; CPQ, cucurbitadienol synthase; CYP, cytochrome P450; DDS, dammarenediol synthase; DM, dammarenediol-II; DMAPP, dimethylallyl diphosphate; FPP, farnesyl pyrophosphate; FPPS (FPS), farnesyl diphosphate synthase; GDP, guanosine diphosphate; Ginsenoside; HEJA, 2-hydroxyethyl jasmonate; HMGR, HMG-CoA reductase; IPP, isopentenyl diphosphate; ITS, internal transcribed spacer; JA, jasmonic acid; JA-Ile, (+)-7-iso-jasmonoyl-l-isoleucine; JAR, JA-amino acid synthetase; JAZ, jasmonate ZIM-domain; KcMS, Kandelia candel multifunctional triterpene synthases; LAS, lanosterol synthase; LUP, lupeol synthase; MEP, methylerythritol phosphate; MVA, mevalonate; MVD, mevalonate diphosphate decarboxylase; MeJA, methyl jasmonate; NDP, nucleotide diphosphate; Non-coding RNAs; OA, oleanane or oleanic acid; OAS, oleanolic acid synthase; OCT, ocotillol; OSC, oxidosqualene cyclase; PPD, protopanaxadiol; PPDS, PPD synthase; PPT, protopanaxatriol; PPTS, PPT synthase; Panax species; RNAi, RNA interference; SA, salicylic acid; SE (SQE), squalene epoxidase; SPL, squamosa promoter-binding protein-like; SS (SQS), squalene synthase; SUS, sucrose synthase; TDP, thymine diphosphate; Transcription factors; UDP, uridine diphosphate; UGPase, UDP-glucose pyrophosphosphprylase; UGT, UDP-dependent glycosyltransferase; WGD, whole genome duplication; α-AS, α-amyrin synthase; β-AS, β-amyrin synthase.