First Report of Pectobacterium aroidearum Causing Soft Rot of Pinellia ternata in China.

Pinelliae rhizoma is the dried tuber of Pinellia ternata (Thunb.) Breit., and has been used for thousand of years in traditional Chinese medicine as an antivomit, anticough, and analgesic (Ying et al. 2007). In September 2022, P. ternata planted in Bijie, Guizhou Province, showed severe soft rot symptoms with incidence of about 50%. The diseased plants showed water-soaked symptoms and produced a foul soft rot smell, and finally the whole plant collapsed. Lesions were first observed at the tip of a leaf or wound, and symptoms of the disease spread rapidly, with the entire plant collapsing and dying within a week. The tissue sections of six plants with typical symptoms from the diseased field were disinfected with 75% ethanol for 30 seconds and 0.3% NaClO for 3 minutes. The tissue sections were then washed with sterile water for three times. A small piece of tissue (5x5mm) was removed from the edge of the lesion and mashed in a 1.5 ml centrifuge tube containing 20 µl of sterile water. The tissue liquid was then diluted 100 times with prepared sterile water. The bacteria were streaked on LB (tryptone/yeast extract/NaCl) AGAR medium and cultured at 37°C for 48 h (Kravitz, 1962). Isolated colonies were streaked on Luria-Bertani (LB) AGAR medium to obtain single colonies for further identification. A total of 13 representative isolates were selected for PCR amplification using primers targeting the conserved region of the 16S rDNA gene, which were in turn analyzed via the BLASTn search engine on the NCBI website. The results of the analysis revealed that seven of the isolates were similar to P. aroidearum strain SCRI 109 (GenBank accession no. NR_159926), with strain BX13 exhibiting the highest similarity to P. aroidearum (99.93% similarity), and therefore, this strain was selected for further investigation. The strain BX13 was incubated on LB solid medium for 24 h at 37 °C, and the single colonies were creamy white, translucent and round, slightly elevated in the center, with smooth surfaces and neat edges (Figure S1 B1). Then,the Scanning Electron Microscope revealed that the thalli of strain BX13 were short rod-shaped and somewhat blunt round at both ends (Figure S1 B2). The steward genes (icdA, gapA, proA) of BX13 were amplified and sequenced for further identification. The sequences of the amplified fragments were all deposited in GenBank 16S rDNA (OQ874505,) icdA (OQ954122)，gapA (OQ954123), proA (OQ954124). Sequence analysis using the BLASTn program at the NCBI revealed gene icdA, gapA, and proA had 100% identity to P. aroidearum strain QJ002 (GenBank accession no. CP090597).. Meanwhile, a maximum likelihood phylogenetic tree was constructed based on multigene sequence analysis of BX13 16S rDNA and steward genes (gapA, icdA, proA) by MEGA X (Liang et al. 2022). Phylogenetic results also showed that BX13 and P. aroidearum strain QJ002 gathered in the same clade(Figure S2). Accordingly, the morphological and molecular characteristics of strain BX13 indicate that it is P. aroidearum. (Nabhan S., et al.2013,Xu et al. 2020). In order to confirm the pathogenicity of strain BX13, a bacterial suspension containing 107 CFU/ml (10 ml/ inoculation point) was injected into the base of a one-week-old P. ternata stems, control seedlings were inoculated with sterile water, inoculated and control seedlings (each of six plants) were kept in a growth chamber maintained at 26°C with a relative humidity range of 70% to 80%. Plants were watered as needed. After 3 days, the stem base of the plants inoculated with bacteria solution showed water-soaked necrosis and stems began to rot, while the plants inoculated with water did not show this symptom. The strains were then successfully re-isolated from the symptomatic P. ternata. Then the strain re-isolated was identified using the BLASTn program at the NCBI and found that it has the same 16S rDNA, icdA, gapA, and proA sequences as strain BX13, thus completing the Koch's postulates. To our knowledge, this is the first report of P. aroidearum causing P. ternata soft rot in China, which expands its known host range. Accordingly, this study provides essential information for the breeding of P. ternata resistant to bacterial soft rot and the development of control measures in China.

Characterization of Arnebia euchroma PGT homologs involved in the biosynthesis of shikonin.

Shikonin is a red naphthoquinone natural product from plants with high economical and medical values. The para-hydroxybenzoic acid geranyltransferase (PGT) catalyzes the key regulatory step of shikonin biosynthesis. PGTs from Lithospermum erythrorhizon have been well-characterized and used in industrial shikonin production. However, its perennial medicinal plant Arnebia euchroma accumulates much more pigment and the underlying mechanism remains obscure. Here, we discovered and characterized the different isoforms of AePGTs. Phylogenetic study and structure modeling suggested that the N-terminal of AePGT6 contributed to its highest activity among 7 AePGTs. Indeed, AePGT2 and AePGT3 fused with 60 amino acids from the N-terminal of AePGT6 showed even higher activity than AePGT6, while native AePGT2 and AePGT3 don't have catalytic activity. Our result not only provided a mechanistic explanation of high shikonin contents in Arnebia euchroma but also engineered a best-performing PGT to achieve the highest-to-date production of 3-geranyl-4-hydroxybenzoate acid, an intermedium of shikonin.

Catalytic promiscuity of O-methyltransferases from Corydalis yanhusuo leading to the structural diversity of benzylisoquinoline alkaloids.

O-methyltransferases play essential roles in producing structural diversity and improving the biological properties of benzylisoquinoline alkaloids (BIAs) in plants. In this study, Corydalis yanhusuo, a plant used in traditional Chinese medicine due to the analgesic effects of its BIA-active compounds, was employed to analyze the catalytic characteristics of O-methyltransferases in the formation of BIA diversity. Seven genes encoding O-methyltransferases were cloned, and functionally characterized using seven potential BIA substrates. Specifically, an O-methyltransferase (CyOMT2) with highly efficient catalytic activity of both 4'- and 6-O-methylations of 1-BIAs was found. CyOMT6 was found to perform two sequential methylations at both 9- and 2-positions of the essential intermediate of tetrahydroprotoberberines, (S)-scoulerine. Two O-methyltransferases (CyOMT5 and CyOMT7) with wide substrate promiscuity were found, with the 2-position of tetrahydroprotoberberines as the preferential catalytic site for CyOMT5 (named scoulerine 2-O-methyltransferase) and the 6-position of 1-BIAs as the preferential site for CyOMT7. In addition, results of integrated phylogenetic molecular docking analysis and site-directed mutation suggested that residues at sites 172, 306, 313, and 314 in CyOMT5 are important for enzyme promiscuity related to O-methylations at the 6- and 7-positions of isoquinoline. Cys at site 253 in CyOMT2 was proved to promote the methylation activity of the 6-position and to expand substrate scopes. This work provides insight into O-methyltransferases in producing BIA diversity in C. yanhusuo and genetic elements for producing BIAs by metabolic engineering and synthetic biology.

Phylogenomics and Genetic Diversity of Arnebiae Radix and Its Allies (Arnebia, Boraginaceae) in China.

Arnebiae Radix is a traditional medicine with pleiotropic properties that has been used for several 100 years. There are five species of Arnebia in China, and the two species Arnebia euchroma and Arnebia guttata are the source plants of Arnebiae Radix according to the Chinese Pharmacopoeia. Molecular markers that permit species identification and facilitate studies of the genetic diversity and divergence of the wild populations of these two source plants have not yet been developed. Here, we sequenced the chloroplast genomes of 56 samples of five Arnebia species using genome skimming methods. The Arnebia chloroplast genomes exhibited quadripartite structures with lengths from 149,539 and 152,040 bp. Three variable markers (rps16-trnQ, ndhF-rpl32, and ycf1b) were identified, and these markers exhibited more variable sites than universal chloroplast markers. The phylogenetic relationships among the five Arnebia species were completely resolved using the whole chloroplast genome sequences. Arnebia arose during the Oligocene and diversified in the middle Miocene; this coincided with two geological events during the late Oligocene and early Miocene: warming and the progressive uplift of Tianshan and the Himalayas. Our analyses revealed that A. euchroma and A. guttata have high levels of genetic diversity and comprise two and three subclades, respectively. The two clades of A. euchroma exhibited significant genetic differences and diverged at 10.18 Ma in the middle Miocene. Three clades of A. guttata diverged in the Pleistocene. The results provided new insight into evolutionary history of Arnebia species and promoted the conservation and exploitation of A. euchroma and A. guttata.

[Problems and strategy of further development of Chinese medicinal materials with edible values].

"Medicine and food homology" is a precious health care concept rooted in the culture of Chinese medicine and plays an important role in the development of the national health industry. It is consistent with the current global trend that food and medicine are mutually penetrating. Accordingly, the Chinese medicinal materials with edible values have an increasing production scale. Especially, in the context that the development of Chinese medicinal materials is switching from pursuing quantity to quality, the food field has become the main market for the new production capacity of Chinese medicinal materials, which has presented a broad prospect. However, the quality standards of raw materials, production methods, and administration ways vary between the materials for edible and medicinal purposes. Specifically, the food for medicinal use on the market cannot meet the quality standards of medicinal mate-rials, while the medicinal materials fail to meet the taste requirements as food. As a result, these problems cause difficulties in market circulation and supervision. In this paper, we analyzed the formation of Chinese medicinal materials with edible values, compared the food with medicinal value, common food, and functional food, and analyzed the different quality requirements of Chinese medicinal materials used in different scenarios. Further, we advised the differential development of Chinese medicinal materials in different directions(edible or medicinal use) from production to supervision. Including:(1) In the variety registration of Chinese medicinal materials with edible values, the variety breeding direction should be announced according to the requirements that medicinal materials care more about the content of active ingredients and food use materials preferentially need to meet the requirements of edible palatability.(2) Differentiation can be reflected in the selection of cultivation mode and planting and processing technology of medicinal materials, The differential production technical specification of medicinal materials with edible values should be developed. Such as the "simulated cultivation" mode is encouraged in the plant of medicinal materials to ensure its quality and the strict management of inputs and sufficient cultivation years should be guaranteed. While for edible medicinal materials, more kinds of cultivation techniques can be selected according to their processing methods.(3) The market supervision of medicinal materials with edible values should be guided by the purpose of their sales and use, which depends on the accurately recognize of the relationship between the properties of medicinal materials with edible values and the situation of pharmacopeia collection.(4) During publicity, when used as ordinary food and health food medi-cinal materials, it should be noticed that the publicity of the product's efficacy must meet the requirements of corresponding regulations.

[Analysis of economic benefits of Chinese medicine eco-agriculture based on multiple stakeholders].

As the most advanced environment-friendly production model in the international society, ecological agriculture of Chinese materia medica(CMM) is the only way for the development of modern agriculture. With the proposal of the declaration on ecolo-gical agriculture of CMM, "Don't grab land from farmland, don't be enemies of grass and insects, don't be afraid of barren slopes and forests, and live up to the green and green mountains", the ecological planting of CMM has blossomed all over the country, and formed a scientific theory, technology and model. Based on the theory and method of economics, this paper expounds the comprehensive benefits and development advantages of ecological agriculture of CMM from the perspectives of farmers(producers), patients(consumers) and the country. From the perspective of medicinal farmers, the input and output income of conventional agriculture and ecological agriculture of CMM such as Panax ginseng, Astragalus propinquus, Atractylodes lancea, and Bupleurum chinense were compared, and it was found that ecological agriculture of CMM had obvious advantages in net income, average annual income and input-output ratio, which could better promote farmers' income. From the perspective of patients, according to the same dose, the content of active ingredients in ecologically planted CMMs is significantly higher than that in conventionally-planted herbs, and the amount of effective substances taken by patients is also higher, so as to achieve better therapeutic effect. At the national level, ecological planting of CMM is the key to ensuring the high-quality development of CMM industry, increasing farmers' income, ensuring the safety of people's drug use and promoting the sustainable development of agriculture. It is also an important part of realizing the harmonious development of economy, society and environment and promoting ecological civilization. In general, the declaration on ecological agriculture of CMM embo-dies the core characteristics and goals of ecological agriculture, and also points of the path and vision of ecological agriculture of CMM in the future. The declaration will guide production practice, promote the benefit of farmers, and lay the foundation for the sustainable development of CMM industry.

[Effect of combined application of inorganic and organic fertilizers on growth and quality of Salvia miltiorrhiza].

The study is aimed through field experiments to study the effect of combined application of organic and chemical fertilizers on the growth and quality of Salvia miltiorrhiza, provide ideas for reducing fertilization while increasing the efficiency as well as improving the quality of produces. The experiment included 6 treatments viz., no fertilization(CK), full application of chemical fertilizer(F), 25% orga-nic fertilizer with 75% chemical fertilizer(M25), 50% organic fertilizer with 50% chemical fertilizer(M50), 75% organic fertilizer with 25% chemical fertilizer(M75), and fully apply organic fertilizer(M100). The results showed that:(1)from the perspective of yield and economic benefits, M75 was the best and M100 second;(2)for effective components, the combined application of organic and chemical fertilizers increased the content of main water-soluble components and the total content of effective components, among which M25 and M50 were better.

[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.

Expansion within the CYP71D subfamily drives the heterocyclization of tanshinones synthesis in Salvia miltiorrhiza.

Tanshinones are the bioactive nor-diterpenoid constituents of the Chinese medicinal herb Danshen (Salvia miltiorrhiza). These groups of chemicals have the characteristic furan D-ring, which differentiates them from the phenolic abietane-type diterpenoids frequently found in the Lamiaceae family. However, how the 14,16-epoxy is formed has not been elucidated. Here, we report an improved genome assembly of Danshen using a highly homozygous genotype. We identify a cytochrome P450 (CYP71D) tandem gene array through gene expansion analysis. We show that CYP71D373 and CYP71D375 catalyze hydroxylation at carbon-16 (C16) and 14,16-ether (hetero)cyclization to form the D-ring, whereas CYP71D411 catalyzes upstream hydroxylation at C20. In addition, we discover a large biosynthetic gene cluster associated with tanshinone production. Collinearity analysis indicates a more specific origin of tanshinones in Salvia genus. It illustrates the evolutionary origin of abietane-type diterpenoids and those with a furan D-ring in Lamiaceae.

[Establishment of RNA interfered hairy root system of two CYP450 genes in Arnebia euchroma and its influence].

In this study, based on the transcriptome database of suspension cells of Arnebia euchroma, we explored two candidate cytochrome P450 enzyme genes that might relate to the shikonin biosynthesis downstream pathway when CYP76B74 sequence was referenced. We constructed interference-type hairy roots of candidate genes and cultured them. We measured the fresh weight, dry weight, total naphthoquinone content, shikonin and its derivatives content and expression levels of key enzyme genes involved in shikonin biosynthesis pathway. The effects of candidate genes on the growth and shikonin production of A. euchroma hairy roots were discussed, and the possible regulatory mechanisms that candidate genes affected shikonin synthesis were discussed. Through local Blast and phylogenetic analysis, two candidate CYP450 genes(CYP76B75 and CYP76B100) with high homology to CYP76B74 in A. euchroma were screened, and corresponding interference hairy roots were constructed. Compared with the control(RNAi-control), the fresh weight of CYP76B75 interfered hairy root(RNAi-CYP76B75) and CYP76B100 interfered hairy root(RNAi-CYP76B100) were significantly reduced, while dry weight were not affected, so the dry rate increased significantly. Except for ß-acetoxyisovalerylalkannin, which is high in three groups of hairy roots, the contents of shikonin, deoxyshikonin, acetylshikonin, ß,ß'-dimethacrylicalkannin, ß-hydroxyisovalerylshikonin,ß-hydroxyisovalerylshikonin, isobutyrylshikonin and total naphthoquinones showed a consistent pattern: RNAi-CYP76B75>RNAi-CYP76B100>RNAi-control. Among them, the synthesis of ß-hydroxyisovalerylshikonin was most significantly promoted by interfering with the expression of CYP76B75. The content of ß-hydroxyisovalerylshikonin in RNAi-CYP76B75 was 11.7 times that of RNAi-control. RESULTS:: of real-time qPCR analysis showed that compared to RNAi-control, the expression levels of AePGT gene in RNAi-CYP76B75 and RNAi-CYP76B100 were not changed significantly, and the expression levels of CYP76B74 and AeHMGR were up-regulated. In addition, the expression level of CYP76B100 in RNAi-CYP76B75 was down-regulated, whereas in RNAi-CYP76B100, the expression of CYP76B75 was significantly up-regulated. Therefore, this study confirmed that when the expression of CYP76B75 and CYP76B100 were interrupted, the growth of hairy roots were suppressed, but the synthesis of shikonin were promoted. They might increase the shikonin biosynthesis by up-regulating the expression of CYP76B74 in the hairy roots of A. euchroma.

[Strategies for medicinal plants adapting environmental stress and "simulative habitat cultivation" of Dao-di herbs].

This paper analyzed life form, habitats and environmental stresses of medicinal plants and algal fungi collected in Chinese Pharmacopoeia(2015). ①It was found that only 0.94% of the medicinal plants mainly cultivated in field. The most common habitats of medicinal plants are divided into two types: those whose natural habitats are forest margins/undergrowth(about 42.53%) and those whose natural habitats are roadside, hillside, wasteland/sand(about 43.78%). The former mainly faces environmental stresses such as weak light, pests and diseases; the latter often faces the main environmental stresses of drought, strong light, ultraviolet radiation, high temperature, low temperature(day and night or annual temperature difference is large), nutrient deficiency, pests and so on. ②Based on analyzing the strategies of medicinal plants to adapt to environmental stresses, it is pointed out that the synthesis and accumulation of secondary metabolites are the most important strategies of medicinal plants to protect against environmental stresses. In the process of long-term adaptation to specific stress, the accumulation of relevant genetic variation and epigenetic inheritance has become an important condition for the formation of quality of medicinal plants. ③It is proposed that "simulative habitat cultivation" has obvious advantages in balancing growth and secondary metabolism and guaranting the quality of traditional Chinese medicinal materials.

[Pattern and matching technology of ecological planting for Chinese materia medica based on system level].

The ecological agriculture of Chinese materia medica(CMM) has become the most dynamic and promising new field in the global ecological agriculture. The development of ecological planting of CMM has become the national strategy of Chinese traditional medicine agriculture. It has been highly valued and has flourished throughout the country, and has formed some more mature ecological planting models of CMM. Based on the system level, this paper sorts out the common ecological cultivation patterns of CMM, and obtains five basic patterns: landscape pattern at the ecological landscape level, circulation pattern at the ecosystem level, stereo model at the bio-community level, biodiversity patterns at the level of biological populations and well-established models at the level of biological individuals. On this basis, eight common ecological planting techniques of CMM were obtained, includingwild tending techniques, fine agricultural farming techniques, directional cultivation techniques, soil improvement techniques, soil testing and fertilization techniques, mycorrhizal cultivation techniques, green control technology for pests and diseases and facility cultivation techniques.This paper aims to provide theoretical basis for scientific research and popularization and application of CMM ecological planting.

[Pattern of ecological planting for Chinese materia medica based on regional distribution].

As an environment-friendly agriculture, ecological agriculture of Chinese materia medica(CMM) is being implemented in all parts of the country. Due to the stronger dependence on natural environmental conditions, ecological agriculture of CMM shows obvious regional differences in production practice. More mature CMM ecological planting patterns representative of each region were collected. It was found that common types of patterns in various regions of the country mainly included intercropping,intercropping,rotation planting mode, undergrowth planting mode, wild tending planting mode and landscape ecological planting mode. Based on the Construction Plan of National Dao-di Herbs Production Base(2018-2025) and Chinese Medicine Division, this paper systematically sorts out the pattern of ecological planting of CMM in the 8-avenue medicinal materials production areas according to the varieties and regions. The specific pattern of ecological planting of CMM included the ginseng undergrowth planting pattern in northeastern China, the bionics wild ecological planting of the Forsythia suspensa in northern China, the Fritillaria thunbergii-rice rotation in eastern China, the imitation wild planting pattern under the Polygonatum cyrtonema in central China, the planting pattern of the Fructus amomi under forest in southern China, the Ligusticum chuanxiong-rice rotation pattern in the Southwest, wild tending of Glycyrrhiza uralensis in the Northwest, and rhubarb imitation wild planting pattern in Qinghai-Tibet area. Finally, it is expected to provide reference for the screening and popularization of ecological planting patterns of other CMMs in various distribution areas.

[Cultivation strategy on cluster brand of ecological agriculture of Dao-di herbs].

The cluster brand is the embodiment of the core competitiveness of an industry. Developing and cultivating cluster brand of ecological agriculture of Dao-di herbs not only helps to optimize the value chain of the Chinese medicinal materials(CMMs) industry cluster, realize the value-added of the CMMs industry cluster, but also enhance the visibility and influence of the industrial cluster, enhance the core competitiveness of the industrial cluster. This has important practical significance for promoting the "orderly" "safe" and "effective" development of the Dao-di herbs. Based on the industry development status of CMMs, this article introduces several concepts related to cluster brands and their relationships, and focuses on the cultivation models and strategies of cluster brand in the CMMs industry. Based on the current status of the development of the CMMs industry, this article introduces several concepts related to cluster brands and their interrelationships. It discusses the cultivation models and strategies of cluster brands in the CMMs industry, industry associations, Chinese medicine companies and individual growers as the support, insists on the ecological cultivation of authentic medicinal materials and the cultivation of cluster brands. Finally, it points out the direction for the high-quality development of the ecological agriculture of CMMs.

[Core position of secondary metabolism of medicinal plants in ecological planting of Chinese materia medica and its utilization].

This paper summarized the effects of ecological planting on secondary metabolism firstly and pointed out that ecological planting can increase the content of secondary metabolites in plants, especially the content of defensive secondary metabolites. The possible mechanism was analyzed subsequently. Then, we reviewed the induction and utilization of secondary metabolism in the ecological planting of Chinese materia medica from the perspectives of biological control of pests and diseases, promotion of beneficial microorganism accumulation, optimization of mixed planting, regulation of no-tillage and straw cover. In this article, we pointed out that paying close attention to secondary metabolism is the most important feature of ecological planting of Chinese materia medica. Ecological planting can promote the accumulation of secondary metabolites of Chinese materia medica which means can improve the quality of Chinese materia medica, beneficial to the prevention and control of diseases, insects and weeds. Furthermore, lacking of systemic researches,the extensive verifications and systematic in-depth researches on the ecological planting of Chinese materia medica should be carry out urgently.

Functional characterization of three flavonoid glycosyltransferases from Andrographis paniculata.

Andrographis paniculata is an important traditional medicinal herb in South and Southeast Asian countries with diverse pharmacological activities that contains various flavonoids and flavonoid glycosides. Glycosylation can transform aglycones into more stable, biologically active and structurally diverse glycosides. Here, we report three glycosyltransferases from the leaves of A. paniculata (ApUFGTs) that presented wide substrate spectra for flavonoid glycosylation and exhibited multi-site glycosylation on the substrate molecules. They acted on the 7-OH position of the A ring and were able to glycosylate several other different types of compounds. The biochemical properties and phylogenetic analysis of these glycosyltransferases were also investigated. This study provides a basis for further research on the cloning of genes involved in glycosylation from A. paniculata and offers opportunities for enhancing flavonoid glycoside production in heterologous hosts. These enzymes are expected to become effective tools for drug discovery and for the biosynthesis of derivatives via flavonoid glycosylation.

Production of 3-geranyl-4-hydroxybenzoate acid in yeast, an important intermediate of shikonin biosynthesis pathway.

Shikonin and its derivatives are the main active components in the medicinal plant Arnebia euchroma and possess extensive pharmaceutical properties. In this study, we developed an optimized yeast system to obtain high-level production of 3-geranyl-4-hydroxybenzoate acid (GBA), an important intermediate involved in shikonin biosynthesis pathway. For host selection, recombinant expression of p-hydroxybenzoate:geranyltransferase (PGT) derived from A. euchroma was performed in Saccharomyces cerevisiae WAT11U strain and high yield monoterpene strain. In shake flask culture with 1 mM p-hydroxybenzoate acid (PHBA), they could yield GBA at 0.1567 and 20.8624 mg L-1, respectively. Additionally, AePGT6 showed higher enzymatic activity than its homologs. Moreover, by combining improvement in the homologous mevalonate pathway with reconstruction in the heterologous shikimic pathway, a de novo GBA synthesis pathway was constructed in StHP6tHC with co-overexpressed SctHMG1, optimized EcUbiC and AePGT6. A high titer of 179.29 mg L-1 GBA was achieved in StHP6tHC under shake flask fermentation with 1 mM PHBA. These results suggest that yeast could be engineered systematically to enable an efficient monoterpene-quinone or naphthoquinone production.

Exploring the catalytic promiscuity of a new glycosyltransferase from Carthamus tinctorius.

The catalytic promiscuity of a new glycosyltransferase (UGT73AE1) from Carthamus tinctorius was explored. UGT73AE1 showed the capability to glucosylate a total of 19 structurally diverse types of acceptors and to generate O-, S-, and N-glycosides, making it the first reported trifunctional plant glycosyltransferase. The catalytic reversibility and regioselectivity were observed and modeled in a one-pot reaction transferring a glucose moiety from icariin to emodin. These findings demonstrate the potential versatility of UGT73AE1 in the glycosylation of bioactive natural products.

[Chemical constituents from cell suspension cultures of Cudrania tricuspidata].

Ten compounds were isolated and purified from cell suspension cultures of Cudrania tricuspidata with silica-gel column chromatography, semi-preparative HPLC and Sephadex LH-20. On the base of their physicochemical properties and spectral data, their structures were identified as 1, 3, 5-trihydroxy4-(3, 3-dimethylallyl) xanthone (1), wighteone (2), 6-prenylapigenin (3), licoflavone C(4), cudraflavanone C(5), erythrivarone A (6), derrone (7), carthamidin (8), genistein (9) and aromadendrin (10). Among them, compounds 2-10 were flavonoids, and compound 1 was a xanthone which was isolated from the plant for the first time.