Dataset Information

A specialized flavone biosynthetic pathway has evolved in the medicinal plant, Scutellaria baicalensis.

ABSTRACT: Wogonin and baicalein are bioactive flavones in the popular Chinese herbal remedy Huang-Qin (Scutellaria baicalensis Georgi). These specialized flavones lack a 4'-hydroxyl group on the B ring (4'-deoxyflavones) and induce apoptosis in a wide spectrum of human tumor cells in vitro and inhibit tumor growth in vivo in different mouse tumor models. Root-specific flavones (RSFs) from Scutellaria have a variety of reported additional beneficial effects including antioxidant and antiviral properties. We describe the characterization of a new pathway for the synthesis of these compounds, in which pinocembrin (a 4'-deoxyflavanone) serves as a key intermediate. Although two genes encoding flavone synthase II (FNSII) are expressed in the roots of S. baicalensis, FNSII-1 has broad specificity for flavanones as substrates, whereas FNSII-2 is specific for pinocembrin. FNSII-2 is responsible for the synthesis of 4'-deoxyRSFs, such as chrysin and wogonin, wogonoside, baicalein, and baicalin, which are synthesized from chrysin. A gene encoding a cinnamic acid-specific coenzyme A ligase (SbCLL-7), which is highly expressed in roots, is required for the synthesis of RSFs by FNSII-2, as demonstrated by gene silencing. A specific isoform of chalcone synthase (SbCHS-2) that is highly expressed in roots producing RSFs is also required for the synthesis of chrysin. Our studies reveal a recently evolved pathway for biosynthesis of specific, bioactive 4'-deoxyflavones in the roots of S. baicalensis.

SUBMITTER: Zhao Q

PROVIDER: S-EPMC4846459 | biostudies-literature | 2016 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A specialized flavone biosynthetic pathway has evolved in the medicinal plant, Scutellaria baicalensis.

Zhao Qing Q Zhang Yang Y Wang Gang G Hill Lionel L Weng Jing-Ke JK Chen Xiao-Ya XY Xue Hongwei H Martin Cathie C

Science advances 20160408 4

Wogonin and baicalein are bioactive flavones in the popular Chinese herbal remedy Huang-Qin (Scutellaria baicalensis Georgi). These specialized flavones lack a 4'-hydroxyl group on the B ring (4'-deoxyflavones) and induce apoptosis in a wide spectrum of human tumor cells in vitro and inhibit tumor growth in vivo in different mouse tumor models. Root-specific flavones (RSFs) from Scutellaria have a variety of reported additional beneficial effects including antioxidant and antiviral properties. W ...[more]

PMID: 27152350

Similar Datasets

Project description:BackgroundCultivation of medicinal plants is not only a means for meeting current and future demands for large volume production of plant-based drug and herbal remedies, but also a means of relieving harvest pressure on wild populations. Scutellaria baicalensis Georgi (Huang-qin or Chinese skullcap) is a very important medicinal plant in China. Over the past several decades, wild resource of this species has suffered rapid declines and large-scale cultivation was initiated to meet the increasing demand for its root. However, the genetic impacts of recent cultivation on S. baicalensis have never been evaluated. In this study, the genetic diversity and genetic structure of 28 wild and 22 cultivated populations were estimated using three polymorphic chloroplast fragments. The objectives of this study are to provide baseline data for preserving genetic resource of S. baicalensis and to evaluate the genetic impacts of recent cultivation on medicinal plants, which may be instructive to future cultivation projects of traditional Chinese medicinal plants.ResultsThirty-two haplotypes of S. baicalensis (HapA-Y and Hap1-7) were identified when three chloroplast spacers were combined. These haplotypes constituted a shallow gene tree without obvious clusters for cultivated populations, suggesting multiple origins of cultivated S. baicalensis. Cultivated populations (hT = 0.832) maintained comparable genetic variation with wild populations (hT = 0.888), indicating a slight genetic bottleneck due to multiple origins of cultivation. However, a substantial amount of rare alleles (10 out of 25 haplotypes within wild populations) lost during the course of S. baicalensis cultivation. The genetic differentiation for cultivated group (GST = 0.220) was significantly lower than that of wild group (GST = 0.701). Isolation by distance analysis showed that the effect of geographical isolation on genetic structure was significant in wild populations (r = 0.4346, P < 0.0010), but not in cultivated populations (r = 0.0599, P = 0.2710). These genetic distribution patterns suggest that a transient cultivation history and the extensive seed change among different geographical areas during the course of S. baicalensis cultivation.ConclusionsAlthough cultivated S. baicalensis maintains comparable genetic diversity relative to wild populations, recent cultivation has still imposed profound impacts on genetic diversity patterns of the cultivated S. baicalensis populations, i.e., the loss of rare alleles and homogenization of cultivated populations. This study suggests that conservation-by-cultivation is an effective means for protecting genetic resources of S. baicalensis, however, the wild resources still need to be protected in situ and the evolutionary consequences of extensive seed exchange mediated by human being should be monitored carefully.

Project description:BackgroundScutellaria baicalensis Georgi has been extensively used as a medicinal herb in China for over 2000 years. They may be intentionally or inadvertently substituted or blended with comparable species in the local market, threatening clinical medication safety. Molecular markers are effective tools to prevent misidentification and eliminate doping and falsification among Scutellaria plants. This study screened four highly variable regions to identify Scutellaria and its adulterants. In addition, a phylogenetic analysis was performed using the complete cp genome combined with published Scutellaria species samples. Moreover, a comparative analysis of the cp genomes was conducted to investigate the cp genome evolution of S. baicalensis.ResultsThe complete cp genome of five species of Scutellaria was sequenced for the first time, and four previously published Scutellaria species were re-sequenced. They all exhibited a conserved quadripartite structure in their cp genomes, including two distinct regions, namely a small and large single copy region, respectively, and two inverted repeats encompassing the majority of ribosomal RNA genes. Furthermore, the nine species exhibited high conservation from aspects of the genome structure, codon usage, repeat sequences, and gene content. Four highly variable regions (matK-rps16, ndhC-trnV-UAC, psbE-petL, and rps16-trnQ-UUG) may function as potential molecular markers for differentiating S. baicalensis from its adulterants. Additionally, the monophyly of Scutellaria was ascertained and could be reclassified into two subgenera, subgenus Anaspis and subgenus Scutellaria, as evidenced by the phylogenetic analyses on sequences of cp genome and shared protein-coding sequences. According to the molecular clock analysis, it has been inferred that the divergence of Scutellaria occurred at approximately 4.0 Mya during the Pliocene Epoch.ConclusionOur study provides an invaluable theoretical basis for further Scutellaria species identification, phylogenetics, and evolution analysis.

Dataset Information

A specialized flavone biosynthetic pathway has evolved in the medicinal plant, Scutellaria baicalensis.

Publications

A specialized flavone biosynthetic pathway has evolved in the medicinal plant, Scutellaria baicalensis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets