Identification and Characterization of CtUGT3 as the Key Player of Astragalin Biosynthesis in Carthamus tinctorius L.

Safflower (Carthamus tinctorius L.) is a multipurpose economic crop that is distributed worldwide. Flavonoid glycosides are the main bioactive components in safflower, but only a few UDP-glycosyltransferases (UGT) have been identified. Three differentially expressed UGT genes related with the accumulation of 9 flavonoid O-glycosides were screened from metabolomics and transcriptome analysis. Safflower corolla protoplasts were used to confirm the glycosylation ability of UGT candidates in vivo for the first time. The astragalin content was significantly increased only when CtUGT3 was overexpressed. CtUGT3 also showed flavonoid 3-OH and 7-OH glycosylation activities in vitro. Molecular modeling and site-directed mutagenesis revealed that G15, T136, S276, and E384 were critical catalytic residues for the glycosylation ability of CtUGT3. These results demonstrate that CtUGT3 has a flavonoid 3-OH glycosylation function and is involved in the biosynthesis of astragalin in safflower. This study provides a reference for flavonoid biosynthesis genes research in nonmodel plants.

Adsorption Mechanism of Benzene Derivatives by Pagoda[n]arenes.

Despite the widespread use in industrial production, benzene derivatives are harmful to both human beings and the environment. The control of these substances has become an important subject of scientific research. This study introduces a new approach for adsorption and separation of benzene derivatives utilizing pagoda[n]arene based supramolecular materials. Density functional theory calculations were employed to investigate the molecular recognition mechanism of benzene derivatives by pagoda[4]arenes and pagoda[5]arenes (Pa[4]As and Pa[5]As). Results indicate that Pa[4]As and Pa[5]As can effectively accommodate benzene derivatives through non-covalent interactions, leading to the formation of stable host-guest complexes. Additionally, molecular dynamics simulations revealed that both crystalline and non-crystalline supramolecular aggregates of Pa[4]As and Pa[5]As possess the ability to adsorb benzene derivatives and maintain the stability of the adsorption. Moreover, increasing the temperature causes benzene derivatives to desorb from the adsorbing aggregates, and thus the material can be reutilized.

The establishment of transient expression systems and their application for gene function analysis of flavonoid biosynthesis in Carthamus tinctorius L.

BACKGROUND: Safflower (Carthamus tinctorius L.) is an important economic crop and a traditional medicinal material rich in flavonoids, which can alleviate cardiovascular and cerebrovascular pathologies. Thus, many candidate genes involved in safflower flavonoid biosynthesis have been cloned. However, owing to the lack of a homologous gene expression system, research on gene function is limited to model plants. Therefore, a gene function identification protocol for safflower must be established. RESULTS: In the present study, using safflower callus as the experimental material, Agrobacterium and biolistic transient expression systems were established. In the Agrobacterium transient expression system, the highest transformation rate was obtained at the original Agrobacterium concentration of OD600 0.4, infiltration concentration of OD600 0.6, infection for 20 min, co-culture for 3 days, and acetosyringone concentration of 100 µmol·L-1. In the biolistic transient expression system, the highest transformation efficiency was observed at helium pressure of 1,350 psi, vacuum degree of -0.8 bar, flight distance of 6.5 cm, one round of bombardment, plasmid concentration of 3 µg·shot-1, and gold particle concentration of 100 µg·shot-1. Further, these two transient expression systems were used for the functional analysis of CtCHS1 as an example. After overexpression, relative CtCHS1 expression increased, particularly in Agrobacterium-transformed calli. Additionally, the contents of some flavonoids were altered; for instance, naringenin and genistein levels were significantly increased in Agrobacterium-transformed calli, whereas luteolin, luteolin-7-O-rutinoside, and apigenin derivative levels were significantly decreased in biolistic-transformed calli. CONCLUSION: Using safflower callus as the experimental material, highly efficient Agrobacterium and biolistic transient expression systems were successfully established, and the utility of both systems for investigating gene function was demonstrated. The proposed safflower callus transient expression systems will be useful for further functional analyses of flavonoid biosynthetic genes in safflower.

Comprehensive review of two groups of flavonoids in Carthamus tinctorius L.

Safflower (Carthamus tinctorius L.) is cultivated in various countries for the flavonoid compounds it contains. These flavonoids have been used in many industries as drugs and/or dyes. Over 60 flavonoids have been isolated from safflower. These flavonoids can be divided into two groups: special and common, both of which are active pharmaceutical ingredients efficacious in the treatment of cardiovascular and cerebrovascular diseases. Gene functions have been studied to figure out the biosynthesis of flavonoids in safflower. However, there is no comprehensive summary of the flavonoids in safflower. Research was recognised through systematic searches of ScienceDirect, PubMed, Web of Science, and CNKI databases by searching terms of "Carthamus tinctorius L.", "safflower", "flavonoid", "pharmacology", and "gene". More than 200 research reports were included after eligibility checks. This study summarizes the application of flavonoids in medicine and other industries. Comprehensively collects the chemical structure information of the two groups of flavonoids, and organic acids, alkaloids, spermidine, polyacetylene, and polysaccharides. The mechanism of two groups of flavonoids in treatment of cardiovascular and cerebrovascular diseases was describe in detail, and pharmacological mechanisms of protecting liver, lung and bone, and anti-cancer and anti-inflammatory were also summarised. Besides, the study updated the latest information on the molecular biology of safflower flavonoids. It is found that two groups of flavonoids in safflower have obvious differences in application, chemical structure, pharmacological mechanism, and biosynthetic pathway. It is hoped that this summative research will provide a new insight to flavonoids research in safflower.

Integrated metabolomics and transcriptome analysis on flavonoid biosynthesis in flowers of safflower (Carthamus tinctorius L.) during colour-transition.

Background: Safflower (Carthamus tinctorius L.), well known for its flower, is widely used as a dye and traditional Chinese medicine. Flavonoids, especially flavonoid glycosides, are the main pigments and active components. However, their biosynthesis is largely unknown. Interestingly, the colour of flowers in safflower changed from yellow to red during flower development, while much of the gene and chemical bases during colour transition are unclear. Methods: In this research, widely targeted metabolomics and transcriptomics were used to elucidate the changes in flavonoid biosynthesis from the gene and chemical points of view in flowers of safflower during colour transition. The screening of differential metabolites depended on fold change and variable importance in project (VIP) value. Differential expressed genes (DEGs) were screened by DESeq2 method. RT-PCR was used to analyse relative expressions of DEGs. Results: A total of 212 flavonoid metabolites, including hydroxysafflor yellow A, carthamin and anthocyanins, were detected and showed a large difference. The candidate genes of glycosyltransferases and flavonoid hydroxylase that might participate in flavonoid glycoside biosynthesis were screened. Ten candidate genes were screened. Through integrated metabolomics and transcriptome analysis, a uridine diphosphate glucose glycosyltransferase gene, CtUGT9 showed a significant correlation with flavonoid glycosides in safflower. In addition, expression analysis showed that CtUGT9 was mainly expressed in the middle development of flowers and was significantly upregulated under MeJA treatment. Our results indicated that CtUGT9 might play an important role in flavonoid glycoside biosynthesis during colour-transition in safflower.

[Global research hot points on cardiovascular disease--bibliometric analysis based on the ESI hot papers].

With the heavier burden of cardiovascular disease, an abundance of papers emerge every year in the research hotspots, which cover a wide range of types and content. In order to let readers interested in the cardiovascular field quickly understand the research hotspots and research frontier, it is necessary to sort out and summarize the research topic in time. According to the discipline classification, we screened papers in cardiovascular field from the Essential Science Indicators (ESI) hot papers published in 2019. Methods such as bibliometrics, statistical description, hierarchical induction, analysis and interpretation were used a step further to reveal the context and characteristics of research in the field of cardiovascular diseases, summarize the latest progress and development direction in this field, and provide information and hints for the expansion of future research directions. A total of 297 papers were finally included, which were mainly in the field of clinical medicine; The country with the most publications was the United States, while China ranked the fifth in terms of contribution; the research institution with the highest number of published papers was Harvard University; the New England Journal of Medicine (NEJM) has published the most papers, with contribution also from journals such as Circulation, Europe Heart Journal, JAMA, and Lancet. All the papers were categorized into disease burden, disease risk, drug treatment, device treatment and surgical treatment, clinical diagnosis, basic research and others, so as to review and summarize the research front in the field of cardiovascular diseases.