[Triterpenoids in Sorbus pohuashanensis suspension cell treated with yeast extract].

This study induced biological stress in Sorbus pohuashanensis suspension cell(SPSC) with yeast extract(YE) as a bio-tic elicitor and isolated and identified secondary metabolites of triterpenoids produced under stress conditions. Twenty-six triterpenoids, including fifteen ursane-type triterpenoids(1-15), two 18,19-seco-ursane-type triterpenoids(16-17), four lupine-type triterpenoids(18-21), two cycloartane-type triterpenoids(22-23), and three squalene-type triterpenoids(24-26), were isolated and purified from the methanol extract of SPSC by chromatography on silica gel, MCI, Sephadex LH-20, and MPLC. Their structures were elucidated by spectroscopic analyses. All triterpenoids were isolated from SPSC for the first time and 22-O-acetyltripterygic acid A(1) was identified as a new compound. Selected compounds were evaluated for antifungal, antitumor, and anti-inflammatory activities, and compound 1 showed an inhibitory effect on NO production in LPS-induced RAW264.7 cells.

[Effects of propiconazole on physiological and biochemical properties of Panax notoginseng and dietary risk assessment].

To study the residue and dietary risk of propiconazole in Panax notoginseng and the effects on physiological and bioche-mical properties of P. notoginseng, we conducted foliar spraying of propiconazole on P. notoginseng in pot experiments. The physiolo-gical and biochemical properties studied included leaf damage, osmoregulatory substance content, antioxidant enzyme system, non-enzymatic system, and saponin content in the main root. The results showed that at the same application concentration, the residual amount of propiconazole in each part of P. notoginseng increased with the increase in the times of application and decreased with the extension of harvest interval. After one-time application of propiconazole according to the recommended dose(132 g·hm~(-2)) for P. ginseng, the half-life was 11.37-13.67 days. After 1-2 times of application in P. notoginseng, propiconazole had a low risk of dietary intake and safety threat to the population. The propiconazole treatment at the recommended concentration and above significantly increased the malondialdehyde(MDA) content, relative conductivity, and osmoregulatory substances and caused the accumulation of reactive oxygen species in P. notoginseng leaves. The propiconazole treatment at half(66 g·hm~(-2)) of the recommended dose for P. ginseng significantly increased the activities of superoxide dismutase(SOD), peroxidase(POD), and catalase(CAT) in P. notoginseng leaves. The propiconazole treatment at 132 g·hm~(-2) above inhibited the activities of glutathione reductase(GR) and glutathione S-transferase(GST), thereby reducing glutathione(GSH) content. Proconazole treatment changed the proportion of 5 main saponins in the main root of P. notoginseng. The treatment with 66 g·hm~(-2) propiconazole promoted the accumulation of saponins, while that with 132 g·hm~(-2) and above propiconazole significantly inhibited the accumulation of saponins. In summary, using propiconazole at 132 g·hm~(-2) to prevent and treat P. notoginseng diseases will cause stress on P. notoginseng, while propiconazole treatment at 66 g·hm~(-2) will not cause stress on P. notoginseng but promote the accumulation of saponins. The effect of propiconazole on P. notoginseng diseases remains to be studied.

[Physiological and biochemical mechanisms of brassinosteroid in improving anti-cadmium stress ability of Panax notoginseng].

In this study, the effect of brassinosteroid(BR) on the physiological and biochemical conditions of 2-year-old Panax notoginseng under the cadmium stress was investigated by the pot experiments. The results showed that cadmium treatment at 10 mg·kg~(-1) inhibited the root viability of P. notoginseng, significantly increased the content of H_2O_2 and MDA in the leaves and roots of P. noto-ginseng, caused oxidative damage of P. notoginseng, and reduced the activities of SOD and CAT. Cadmium stress reduced the chlorophyll content of P. notoginseng, increased leaf F_o, reduced F_m, F_v/F_m, and PIABS, and damaged the photosynthesis system of P. notoginseng. Cadmium treatment increased the soluble sugar content of P. notoginseng leaves and roots, inhibited the synthesis of soluble proteins, reduced the fresh weight and dry weight, and inhibited the growth of P. notoginseng. External spray application of 0.1 mg·L~(-1) BR reduced the H_2O_2 and MDA content in P. notoginseng leaves and roots under the cadmium stress, alleviated cadmium-induced oxidative damage to P. notoginseng, improved the antioxidant enzyme activity and root activity of P. notoginseng, increased the content of chlorophyll, reduced the F_o of P. notoginseng leaves, increased F_m, F_v/F_m, and PIABS, alleviated the cadmium-induced damage to the photosynthesis system, and improved the synthesis ability of soluble proteins. In summary, BR can enhance the anti-cadmium stress ability of P. notoginseng by regulating the antioxidant enzyme system and photosynthesis system of P. notoginseng under the cadmium stress. In the context of 0.1 mg·L~(-1) BR, P. notoginseng can better absorb and utilize light energy and synthesize more nutrients, which is more suitable for the growth and development of P. notoginseng.

[Effect of sulfur fumigation on quality and safety of Lilii Bulbus].

Lilii Bulbus is a commonly used Chinese herbal medicine with both medicinal and edible values, while the market products usually has the problem of sulfur fumigation. Therefore, the quality and safety of Lilii Bulbus products deserve attention. In this study, ultra-high performance liquid chromatography-time of flight-tandem mass spectrometry(UPLC-Q-TOF-MS/MS) was combined with principal component analysis(PCA) and orthogonal partial least squares discriminant analysis(OPLS-DA) to analyze the differential components of Lilii Bulbus before and after sulfur fumigation. We identified ten markers generated after sulfur fumigation, summarized their mass fragmentation and transformation patterns, and verified the structures of phenylacrylic acid markers of sulfur fumigation. At the same time, the cytotoxicity of the aqueous extracts of Lilii Bulbus before and after sulfur fumigation was evaluated. The results showed that in the concentration range of 0-800 mg·L~(-1), the aqueous extract of Lilii Bulbus after sulfur fumigation had no significant effect on the viability of human liver LO2 cells, human renal proximal tubular HK-2 cells, and rat adrenal pheochromocytoma PC-12 cells. Moreover, the viability of the cells exposed to the aqueous extract of Lilii Bulbus before and after sulfur fumigation showed no significant difference. This study identified phenylacrylic acid and furostanol saponins as markers of sulfur-fumigated Lilii Bulbus for the first time, and made clear that proper sulfur fumigation of Lilii Bulbus would not produce cytotoxicity, providing a theoretical basis for the rapid identification and quality and safety control of sulfur-fumigated Lilii Bulbus.

Structure and Bioactivities of a Novel Polysaccharide Extracted From Dendrobium huoshanense by Subcritical Water.

In this study, the polysaccharide was extracted by subcritical water from Dendrobium huoshanense. A novel polysaccharide (DHPs-1) was obtained through several purification steps and its structure and bioactivity were investigated. Structural analysis indicated that the weight-average molecular weight of DHPs-1 was 5.0 × 104 Da and it was mainly composed of glucose (65.04%), mannose (14.23%), galactose (8.17%), galacturonic acid (6.41%), rhamnose (2.34%), and xylose (1.25%). 1,4-Glcp, and 1,4,6-Galp were existed in the backbone of DHPs-1. The residues of 1,3,4-Galp, 1,4-Manp, 1,4-Galp, and 1,3,4,6-Galp could be in the backbone or the side chains with the non-reducing terminal of α-Manp. Bioactivity tests indicated that DHPs-1 had immunomodulatory activity in that it significantly enhanced transcript levels of cytokines [Tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), Interleukin-1ß (IL-1ß), and Interleukin-10 (IL-10)]. DPPH and hydroxyl radical scavenging tests showed that it had good antioxidant activity. These results reveal that DHPs-1 could be developed as a safe immunomodulatory agent and antioxidant for pharmacological or functional food applications.

[Utilization of used fungus-growing materials of Gastrodia elata].

This study aims to explore the resource utilization of used fungus-growing materials produced in the cultivation of Gastrodia elata. To be specific, based on the production practice, this study investigated the recycling mechanism of used fungus-growing materials of G. elata by Phallus inpudicus. To screen edible fungi with wide adaptability, this study examined the allelopathic effects of Armillaria mellea secretions on P. impudicus and 6 kinds of large edible fungi and the activities of enzymes related to degradation of the used fungus-growing materials of G. elata. The results showed that P. impudicus can effectively degrade cellulose, hemicellulose, and lignin in used fungus-growing materials of G. elata. The cellulase activity of A. mellea was significantly higher than that of P. impudicus, and the activities of lignin peroxidase, polyphenol oxidase, and xylanase of P. impudicus were significantly higher than those of A. mellea, which was the important reason why A. mellea and P. impudicus used different parts and components of the used fungus-growing materials to absorb carbon sources and develop ecological niche differences. The growth of P. impudicus was significantly inhibited on the used fungus-growing materials of G. elata. The secretions of A. mellea had allelopathic effects on P. impudicus and other edible fungi, and the allelopathic effects were related to the concentration of allelopathy substances. The screening result showed that the growth and development of L. edodes and A. auricular were not significantly affected by 30% of A. mellea liquid, indicating that they had high resistance to the allelopathy of A. mellea. The results showed that the activities of extracellular lignin peroxidase, polyphenol oxidase, and xylanase of the two edible fungi were similar to those of P. impudicus, and the cellulase activity was higher than that of P. impudicus. This experiment can be further verified by small-scale production tests.

[Advances in research on chemical composition of Picrorhiza scrophulariiflora and P. kurroa and their biological activities].

At present, 141 compounds have been isolated from Picrorhiza scrophulariiflora and P. kurroa of the Scrophulariaceae plants, including 46 iridoid glycosides, 29 tetracyclic triterpenoids, 25 phenylpropanoids, and 11 phenylethanoid glycosides. Pharmacological studies have demonstrated that they have liver-, heart-, brain-, kidney-, and nerve cells-protecting effects as well as anti-tumor, anti-inflammatory, anti-bacterial, anti-asthma, anti-diabetic, immunomodulatory, and blood lipid-lowering activities. This article reviews the chemical components and pharmacological activities of P. scrophulariiflora and P. kurroa, aiming to provide a basis for the in-depth research, development, and utilization of the two plants.

[Screening of zearalenone-degrading bacteria and analysis of degradation conditions].

Zearalenone(ZEN) is a mycotoxin produced by Fusarium, possessing estrogen-like effects, carcinogenicity, and multiple toxicities. To seek more efficient and practical agents for biological detoxification and broaden their application, this study isolated 194 bacterial strains from the moldy tuberous root of Pseudostellaria heterophylla, which were co-cultured with ZEN. An efficient ZEN-degrading strain H4-3-C1 was screened out by HPLC and identified as Acinetobacter calcoaceticus by morphological observation and molecular identification. The effects of culture medium, inoculation dose, culture time, pH, and temperature on the degradation of ZEN by H4-3-C1 strain were investigated. The mechanism of ZEN degradation and the degrading effect in Coicis Semen were discussed. The degradation rate of 5 µg·mL~(-1) ZEN by H4-3-C1 strain was 85.77% in the LB medium(pH 6) at 28 ℃/180 r·min~(-1) for 24 h with the inoculation dose of 1%. The degradation rate of ZEN in the supernatant of strain culture was higher than that in the intracellular fluid and thalli. The strain was inferred to secret extracellular enzymes to degrade ZEN. In addition, the H4-3-C1 strain could also degrade ZEN in Coicis Semen. If the initial content of ZEN in Coicis Semen was reduced from 90 µg·g~(-1) to 40.68 µg·g~(-1), the degradation rate could reach 54.80%. This study is expected to provide a new strain and application technology for the biological detoxification of ZEN in food processing products and Chinese medicinal materials.

[Analysis and evaluation of volatile oil content in leaves of different Artemisia argyi germplasm resources].

Volatile oil is the main effective component and an important quality indicator of Artemisia argyi leaves. In this study, 100 germplasm resources of A. argyi were collected from all the related habitats in China. The total volatile oils in A. argyi leaves were extracted by steam distillation and the content was determined by GC-MS. The result demonstrated that the content of total volatile oils was in the range of 0.53%-2.55%, with the average of 1.43%. A total of 39 chemical constituents were identified from the volatile oils, including 13 shared by the 100 germplasm resources. Clustering analysis of the 39 constituents showed that the 100 A. argyi samples were categorized into groups Ⅰ(9), Ⅱ(2), Ⅲ(66) and Ⅳ(23), and group Ⅲ had the most volatile medicinal components, with the highest content. Five principal components(PCs) were extracted from 13 shared constituents, which explained 73.454% of the total variance. PC1, PC2, and PC3 mainly reflected the pharmacological activity of volatile oils and the rest two the aroma information. The volatile oils identified in this study lay a foundation for variety breeding of and rational utilization of volatile oils in A. argyi leaves.

[Research progress on chemical compositions and pharmacological action of Drynariae Rhizoma].

Drynariae Rhizoma is warm in nature and bitter in taste, mainly acting on liver and kidney systems. It is a common Chinese herbal medicine for the treatment of fracture and bone injury. The chemical compositions of Drynariae Rhizoma mainly include flavonoids, triterpenoids, phenylpropanoids and lignans. At present, modern pharmacological and clinical studies have shown that Drynariae Rhizoma has the effects of anti osteoporosis, promoting fracture healing, kidney protection, anti-inflammatory, promoting tooth growth, preventing and treating aminoglycoside ototoxicity and lowering blood lipid. In addition, the toxicity evaluation experiment of Drynariae Rhizoma has also shown that it has no obvious toxic and side effects. Naringin is a kind of dihydroflavone in Drynariae Rhizoma. Many studies have shown that naringin and other total flavonoids play an important role in anti-osteoporosis, promoting fracture healing, anti-inflammation, promoting tooth growth and lowering blood lipid. In this study, the research progresses on chemical consti-tuents and pharmacological activities of Drynariae Rhizoma in recent years were reviewed, and some mechanisms of action were summarized, to provide references for the further research and development of Drynariae Rhizoma.

[Extraction and separation, structure analysis and biological activity of polysaccharides from Atractylodis Rhizoma].

Atractylodis Rhizoma(AR) is a traditional Chinese medicinal material for food and medicine, with the functions of eli-minating dampness, strengthening the spleen, expelling wind evil and dispersing cold. AR contains a variety of compounds, including sesquiterpenoids, alkynes, triterpenoids, aromatic glycosides, polysaccharides and so on. At present, the researches on AR mainly focus on volatile components, with relatively fewer researches on non-volatile components. Polysaccharide from Atractylodis Rhizoma(ARP) is an important material basis among non-volatile components for the efficacy. Due to its many biological activities such as immunomodulatory activity, anti-tumors, anti-virus and anti-oxidation, ARP has certain research value and potential. The diversity of the polysaccharide structure is the basis for biological functions, but it also increases the difficulty of carbohydrate research. The research on the extraction, separation, purification, structure and activity of ARP is in the preliminary exploration stage, still with many shortcomings. Herein, recent advancements in the extraction, purification, structural characteristics and biological activities of ARP were summarized in this article to provide scientific reference for the in-depth systematic research of ARP and the development of AR resources.

[Cloning and functional verification of carboxyl CoA ligases(AeCCLs) in Arnebia euchroma].

Carboxyl CoA ligases(CCLs) is an important branch of adenylate synthetase gene family, which mainly has two-step catalytic reactions. Firstly, in the presence of adenosine triphosphate, it can catalyze the pyrophosphorylation of carboxylateswith diffe-rent structures to form corresponding acyl adenosine monophosphate intermediates. Secondly, adenosine monophosphate was replaced by free electrons in the mercaptan group of enzyme A or other acyl receptors by nucleophilic attack to form thioesters. In this study, on the basis of the transcriptome database of Arnebia euchroma, two genes were selected, named AeCCL5(XP_019237476.1) and AeCCL7(XP_019237476.1). Bioinformatics analysis showed that their relative molecular weights were 60.569 kDa and 60.928 kDa, theoretical PI were 8.59 and 8.92, respectively. They both have transmembrane domains but without signal peptide. By multiple sequence alignment and phylogenetic tree analysis, we found that the similarity between AeCCLs and other plant homologous proteins was not high, and the substrate binding sites of AeCCLs were not highly conserved. The reasons might be that the sequence and structure need to adapt to the changes of new substrates in the process of evolution. In this study, the full-length of AeCCL5 and AecCCL7 were cloned into the expression vector pCDFDuet-1. The proteins of AeCCL5 and AeCCL7 with His-tag were expressed in Escherichia coli. The proteins of AeCCL5 and AeCCL7 were purified by nickel column. In vitro enzymatic reactions proved that both AeCCL5 and AeCCL7 can participate in the upstream phenylpropane pathway of shikonin biosynthesisby catalyzing 4-coumaric acid to produce 4-coumarin-CoA, and then to synthesis p-hydroxybenzoic acid, which is an important precursor of shikonin biosynthesis in A. euchroma.

[Cloning and functional analysis of caffeic acid and rosmarinic acid glycosyltransferases from Arnebia euchroma].

Caffeic acid and its oligomers are the main water-soluble active constituents of the traditional Chinese medicine(TCM) Arnebiae Radix. These compounds possess multiple biological activities such as antimicrobial, antioxidant, cardiovascular protective, liver protective, anti-liver fibrosis, antiviral and anticancer activities. The phenylpropanoid pathway in plants is responsible for the biosynthesis of caffeic acid and its oligomers. Glycosylation can change phenylpropanoid solubility, stability and toxic potential, as well as influencing compartmentalization and biological activity. In view of the important role played by de-glycosylation in the regulation of phenylpropanoid homeostasis, the biosynthesis of caffeic acid and its oligomers are supposed to be under the control of relative UDP-glycosyltransferases(UGTs). Through the data mining of Arnebia euchroma transcriptome, we cloned 15 full-length putative UGT genes. After recombinant expression using the prokaryotic system, the crude enzyme solution of the putative UGTs was examined for the glycosylation activities towards caffeic acid and rosmarinic acid in vitro. AeUGT_01, AeUGT_02, AeUGT_03, AeUGT_04 and AeUGT_10 were able to glycosylate caffeic acid and/or rosmarinic acid resulting in different mono-and/or di-glycosylated products in the UPLC-MS analyses. The characterized UGTs were distantly related to each other and divided into different clades of the phylogenetic tree. Based on the observation that each characterized UGT exhibited substrate or catalytic similarity with the members in their own clade, we supposed the glycosylation abilities towards caffeic acid and/or rosmarinic acid were evolved independently in different clades. The identification of caffeic acid and rosmarinic acid UGTs from A. euchroma could lead to deeper understanding of the caffeic acid oligomers biosynthesis and its regulation. Furthermore, these UGTs might be used for regiospecific glycosylation of caffeic acid and rosmarinic acid to produce bioactive compounds for potential therapeutic applications.

Bioactive metabolites from the desert plant-associated endophytic fungus Chaetomium globosum (Chaetomiaceae).

Globosumin, an undescribed chromene-4,7(4aH)-dione-tetramic acid PKS-PKS-NRPS hybrid, and globosumone, an undescribed azaphilone, together with ten known metabolites, were isolated from the desert plant-associated endophytic fungus Chaetomium globosum (Chaetomiaceae). The planar structures and relative configurations of globosumin and globosumone were determined by high-resolution ESI-MS and NMR data, and the absolute configurations of these two metabolites were determined by electronic circular dichroism (ECD) and circular dichroism (CD) combined with time-dependent density functional theory (TDDFT)-based quantum-chemical calculations. Chaetoglobosin A displayed biological effects against the seedling growth of Arabidopsis thaliana (Brassicaceae) in a dose-dependent manner, and this compound also exhibited biological activity against two cancer cell lines, A549 and HepG2, with IC50 values of 6.82 ± 2.34 and 38.62 ± 7.44 µM, respectively.

Structural characterization and discrimination of Ophiopogon japonicas (Liliaceae) from different geographical origins based on metabolite profiling analysis.

The root tuber of Ophiopogon japonicus (Thunb.) Ker-Gawl ("Maidong" in Chinese), with steroidal saponins and homoisoflavonoids as its representative chemical compositions, is a representative medicinal herbs with multiple major producing areas. This study aimed to distinguish the O. japonicas samples from Zhejiang and Sichuan by using an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS)-based metabolome analysis. Firstly, a global chemical constituent identification of O. japonicas was carried out by using both automatic and manual methods. An integrated steroidal saponins structural identification strategy in O. japonicas based on exact mass information, fragmentation characteristics and retention time was developed. Overall, 135 steroidal saponins, 47 homoisoflavonoids and 9 other metabolites were quickly identified or tentatively identified from the MSE continuum data. Furthermore, multivariate statistical analysis revealed that O. japonicas from Zhejiang and Sichuan can clearly be separated and some markers were screened. Moreover, some major active components including total soluble sugar, total soluble polyphenol, total flavonoid, total saponin and 10 specific compounds were analyzed quantitatively. In general, these results showed that there were many differences between the metabolic profile data of O. japonicas from different producing areas, O. japonicas from Sichuan showed higher level steroidal saponins and samples from Zhejiang had higher contents of homoisoflavonoids specifically, and indicated that metabolite profiling by UPLC/Q-TOF MS is an effective approach for the discrimination of medicinal herbs from different geographical origins.

Four new phenolic constituents from the rhizomes of Gastrodia elata Blume.

Four new gastrodin derivatives containing a trans-cinnamoyl unit (1-4) and nine known compounds (5-13) were isolated from the rhizomes of Gastrodia elata Blume. All these compounds were evaluated for their neuroprotective effects against 6-hydroxydopamine-induced cell death, and compounds 7 and 12 showed potent activities with EC50 values of 10.5 and 10.2 µM, respectively.

[Research on periodical changes and metabolism relations of active components in Lonicera japonica leaves].

The study is aimed to explore the metabolism rule of Lonicera japonica by investigating the primary and secondary metabolism process in different growth periods. HPLC and other methods were used to measure metabolism indexes of leaves collected in last ten days of every month. The results suggested that the maximum (78.59%) and minimum (60.83%) of water content were found in March and December. The content of total sugar reached a high level from December to February and the maximum (275.8 mg•g⁻¹) appeared in October, while it reduced significantly at other time. The change of chlorogenic acid, neochlorogenic acid, galuteolin, caffeic acid were basically consistent and the highest content of them synchronously appeared (42.79, 2.01, 7.13, 0.16 mg•g⁻¹) in March. The content of primary and secondary metabolite in L. japonica leaves reached a high level from March to May, and the main related elements with effective components were K, Mg, P, aspartate, threonine, proline, valine, cysteine, isoleucine and phenylalanine.

Structural characterization and discrimination of the Paris polyphylla var. yunnanensis and Paris vietnamensis based on metabolite profiling analysis.

This study aimed to distinguish the rhizomes of Paris polyphylla var. yunnanensis (Franch) Hand Mazz (PPY) and Paris veitnamensis (Takht.) H. Li (PV) using metabolomics-based ultra high-performance liquid chromatography coupled with quadrupole time-of-fligh mass spectrometry (UHPLC/Q-TOF MS). First, the UHPLC/Q-TOF MS approach was optimized for metabolite profiling. Then, the MS data were processed using UNIFI™ combined with an in-house library to automatically characterize the metabolites. Based on the exact mass information, the fragmentation characteristics, and the retention time of compounds, and the fragmentation mechanism and retention behavior of steroidal glycosides in the references, the structures identified by UNIFI were further verified. Overall, 146 metabolites, including 42 potential new compounds, were identified or tentatively identified. Pattern recognition analysis of the PPY and PV MS data revealed that they were clearly separated, and 15 potential biomarkers for differentiating between them were selected. These biomarkers were subsequently used to successfully predict the genus of PPY and PV samples. These results indicated that metabolite profiling by UHPLC/Q-TOF MS is an effective, robust approach for determining the characteristic biomarkers that differentiate between TCM species with multiple botanical origins.

[Mitogen-activated protein kinase genes of Artemisia annua and their expression analysis under Cadmium stress].

In order to study Artemisia annua under cadmium stress, whether there are corresponding MAPK genes involved in transduction of the cadmium signal. 17 AaMAPK genes, named AaMAPK1-AaMAPK17 repectively, were finally obtained by using Trinity method for de novo assembly of transcripts from SRA database and BLAST search against AtMAPK genes and determing conserved domain using a series of bioinformatics tools. There exist 16 MAPK genes contained T[D/E]Y conserved domains among the obtained genes. The expressions of these genes were analyzed by Real-time PCR under cadmium stress. The results showed that the expressions level of AaMAPK3 and AaMAPK10 were down-regulated and MAPK7, MAPK9 and MAPK12 were up-regulated. These indicated that there exist corresponding MAPK genes involved in transduction of the cadmium signal.

[Transcriptome-based gene mining and bioinformatics analysis of p-hydroxybenzoate geranyltransferase genes in Arnebia euchroma].

The p-hydroxybenzoate geranyltransferases(PGT) play an important role in the biosynthesis pathways of shikonin derivatives. Six PGTs were obtained from transcriptome datebase of Arnebia euchroma by using bioinformatics methods and the proteins＇physiochemical properties they encoded were predicted. The result of protein domain prediction showed all of the six protein sequences contained the conserved domain of Ubia prenyltransferase family and possessed the motif NDxxDxxxD for prenyldiphosphate binding and a GX(K/Y)STAL sequence for putative aromatic ring binding. The phylogenetic tree showed that PGT and p-hydroxybenzoate polyprenyltransferase(PPT) belonged to two different clades. The results of gene expression analyses showed that the expression levels in the red shikonin-proficient line and the overground part of A. euchroma that could produce shikonin derivatives was much higher than the white shikonin-deficient line and the underground part, which suggested a positive correlation between the expression levels of PGT genes and shikonin production. This study aims to lay a foudation for further understanding of the function and enzymatic properties of PGT and provide a basis for the biosynthesis pathways and metabolic regulation of shikonin derivatives.