Contamination status and exposure risk of mycotoxins in Coicis Semen / 中国中药杂志

By investigating the contamination status and predicting the exposure risk of mycotoxin in Coicis Semen, we aim to provide guidance for the safety supervision of Chinese medicinal materials and the formulation(revision) of mycotoxin limit standards. The content of 14 mycotoxins in the 100 Coicis Semen samples collected from five major markets of Chinese medicinal materials in China was determined by UPLC-MS/MS. The probability evaluation model based on Monte Carlo simulation method was established after Chi-square test and One-way ANOVA of the sample contamination data. Health risk assessment was performed on the basis of margin of exposure(MOE) and margin of safety(MOS). The results showed that zearalenone(ZEN), aflatoxin B_1(AFB_1), deoxynivalenol(DON), sterigmatocystin(ST), and aflatoxin B_2(AFB_2) in the Coicis Semen samples had the detection rates of 84%, 75%, 36%, 19%, and 18%, and the mean contamination levels of 117.42, 4.78, 61.16, 6.61, and 2.13 μg·kg~(-1), respectively. According to the limit standards in the Chinese Pharmacopoeia(2020 edition), AFB_1, AFs and ZEN exceeded the standards to certain extents, with the over-standard rates of 12.0%, 9.0%, and 6.0%, respectively. The exposure risks of Coicis Semen to AFB_1, AFB2, ST, DON, and ZEN were low, while 86% of the samples were contaminated with two or more toxins, which needs more attention. It is suggested that the research on the combined toxicity of different mycotoxins should be strengthened to accelerate the cumulative exposure assessment of mixed contaminations and the formulation(revision) of toxin limit standards.

Methods for synchronous detection of 14 mycotoxins in Pseudostellariae Radix and investigation on its contamination / 中国中药杂志

This study aimed to establish a method for synchronous detection of 14 mycotoxins in Pseudostellariae Radix and investigate its contamination with mycotoxins, so as to provide technical guidance for monitoring the quality of Chinese medicinal materials and medication safety. The sample was extracted with 80% acetonitrile in an oscillator for 1 h, purified using the modified QuEChERS purifying agent(0.1 g PSA + 0.3 g C_(18) + 0.3 g MgSO_4), and separated on a Waters HSS T3 chromatographic column(2.1 mm×100 mm, 1.8 μm). The gradient elution was carried out with 0.1% formic acid in water and acetonitrile, followed by the scanning in the multi-reaction monitoring(MRM) mode and the analysis of mycotoxin contamination in 26 Pseudostellariae Radix samples. The recovery rates of the established method were within the range of 82.17%-113.6%, with the RSD values less than 7% and the limits of quantification(LOQ) being 0.019-0.976 μg·kg~(-1). The detection rate of 14 mycotoxins in 26 batches of medicinal materials was 53.85%. The detection rate of sterigmatocystin(ST) was the highest, followed by those of zearalenone(ZEN), aflatoxin G_2(AFG_2), fumonisin B_1(FB_1), HT-2 toxin, and nivalenol(NIV). Their respective detection rates were 38.46%, 26.92%, 23.08%, 11.54%, 11.54%, and 7.69%, with the pollution ranges being 1.48-69.65, 0.11-31.05, 0.11-0.66, 0.28-0.83, 20.86-42.56, and 0.46-1.84 μg·kg~(-1), respectively. The established method for the detection of 14 mycotoxins is accurate, fast and reliable. The research results have very important practical significance for guiding the monitoring and prevention and control of exogenous fungal contamination of Chinese medicinal materials.

Thoughts and suggestions on ecological cultivation of Gastrodia elata / 中国中药杂志

Due to the special biological characteristics, Gastrodia elata suffers from high resource consumption and low utilization rate in modern agricultural production, which significantly block the green and healthy development of this industry. Based on the theory and technology in ecological cultivation of Chinese medicinal materials, this study analyzed the challenges in ecological cultivation of G. elata, such as waste of fungus material, a few cultivation modes available, continuous cropping obstacles, frequent occurrence of diseases, and poor stability of ecological structure. According to the production practice, the following suggestions were proposed for ecological cultivation of G. elata: following the principle of environmental protection and no pollution, selecting suitable habitats to yield high-quality medicinal materials, committing to green control of diseases and pests, upgrading industrial structure to maximize the benefits, establishing a sound mechanism for protecting the genetic diversity of wild G. elata, carrying out simulative habitat cultivation to improve medicinal material quality, adopting science-based planning of fungus resources to relieve forestry pressure, enhancing the recycling and utilization of fungus materials, and applying diversified cultivation modes to improve the stability of ecological structure. The result is expected to provide a reference for the quality development of G. elata industry.

Resistance of different ecotypes of Gastrodia elata to tuber rot / 中国中药杂志

Tuber rot has become a serious problem in the large-scale cultivation of Gastrodia elata. In this study, we compared the resistance of different ecotypes of G. elata to tuber rot by field experiments on the basis of the investigation of G. elata diseases. The histological observation and transcriptome analysis were conducted to reveal the resistance differences and the underlying mechanisms among different ecotypes. In the field, G. elata f. glauca had the highest incidence of tuber rot, followed by G. elata f. viridis, and G. elata f. elata and G. elata f. glauca×G. elata f. elata showed the lowest incidence. Tuber rot showcased obvious plant source specificity and mainly occurred in the buds and bottom of G. elata plants. After infection, the pathogen spread hyphae in host cortex cells, which can change the endophytic fungal community structure in the cortex and parenchyma of G. elata. G. elata f. glauca had thinner lytic layer and more sugar lumps in the parenchyma than G. elata f. elata. The transcription of genes involved in immune defense, enzyme synthesis, polysaccharide synthesis, carbohydrate transport and metabolism, hydroxylase activity, and aromatic compound synthesis had significant differences between G. elata f. glauca and G. elata f. elata. These findings suggested that the differences in resis-tance to tuber rot among different ecotypes of G. elata may be related to the varied gene expression patterns and secondary metabolites. This study provides basic data for the prevention and control of tuber rot and the improvement of planting technology for G. elata.

Isolation, identification, and pathogenicity research of brown rot pathogens from Gastrodia elata / 中国中药杂志

Brown rot is a common disease in the cultivation and production of Gastrodia elata, but its pathogens have not been fully revealed. In this study, the pathogenic fungi were isolated and purified from tubers of 77 G. elata samples with brown rot. Pathogens were identified by the pathogenicity test and morphological and molecular identification. The pathogenicity of each pathogen and its inhibitory effects on Armillaria gallica were compared. The results showed that 119 strains of fungi were isolated from tubers of G. elata infected with brown rot. Among them, the frequency of separation of Ilyonectria fungi was as high as 42.01%. The pathogenicity test showed that the pathogenicity characteristics of six strains of fungi were consistent with the natural symptoms of brown rot in G. elata. The morphological and molecular identification results showed that the six strains belonged to I. cyclaminicola and I. robusta in the Nectriaceae family of Sordariomycetes class, respectively. Both types of fungi could produce pigments, conidia, and chlamycospore, and the growth rate of I. cyclaminicola was significantly higher than that of I. robusta. The comparison of pathogenicity showed that the spots formed by I. cyclaminicola inoculation were significantly larger than those of I. robusta inoculation, suggesting I. cyclaminicola was superior to I. robusta in pathogenicity. The results of confrontation culture showed that I. cyclaminicola and I. robusta could signi-ficantly inhibit the germination and cordage growth of A. gallica. A. gallica also inhibited the growth of pathogens, and I. cyclaminicola was less inhibited as compared with I. robusta. The results of this study revealed for the first time that I. cyclaminicola and I. robusta were the pathogens responsible for G. elata brown rot.

Correlation analysis between continuous cropping obstacle of Gastrodia elata and Ilyonectria fungi and relieving strategy / 中国中药杂志

The continuous cropping obstacle of Gastrodia elata is outstanding, but its mechanism is still unclear. In this study, microbial changes in soils after G. elata planting were investigated to explore the mechanism correlated with continuous cropping obstacle. The changes of species and abundance of fungi and bacteria in soils planted with G. elata after 1, 2, and 3 years were compared. The pathogenic fungi that might cause continuous cropping diseases of G. elata were isolated. Finally, the prevention and control measures of soil-borne fungal diseases of G. elata were investigated with the rotation planting pattern of "G. elata-Phallus impudicus". The results showed that G. elata planting resulted in the decrease in bacterial and fungal community stability and the increase in harmful fungus species and abundance in soils. This change was most obvious in the second year after G. elata planting, and the soil microbial community structure could not return to the normal level even if it was left idle for another two years. After G. elata planting in soils, the most significant change was observed in Ilyonectria cyclaminicola. The richness of the Ilyonectria fungus in soils was significantly positively correlated with the incidence of G. elata diseases. When I. cyclaminicola was inoculated in the sterile soil, the rot rate of G. elata was also significantly increased. After planting one crop of G. elata and one to three crops of P. impudicus, the fungus community structure in soils gradually recovered, and the abundance of I. cyclaminicola decreased year by year. Furthermore, the disease rate of G. elata decreased. The results showed that the cultivation of G. elata made the Ilyonectria fungi the dominant flora in soils, and I. cyclaminicola served as the main pathogen of continuous cropping diseases of G. elata, which could be reduced by rotation planting with P. impudicus.

Construction of protoplast genetic transformation system for Mycena--symbiont of Gastrodia elata / 中国中药杂志

Mycena, a symbiont of Gastrodia elata, promotes seed germination of G. elata and plays a crucial role in the sexual reproduction of G. elata. However, the lack of genetic transformation system of Mycena blocks the research on the interaction mechanism of the two. In order to establish the protoplast transformation system of Mycena, this study analyzed the protoplast enzymatic hydrolysis system, screened the resistance markers and regeneration medium, and explored the transient transformation. After hydrolysis of Mycena hyphae with complexes enzymes for 8 h and centrifugation at 4 000 r·min~(-1), high-concentration and quality protoplast was obtained. The optimum regeneration medium for Mycena was RMV, and the optimum resistance marker was 50 mg·mL~(-1) hygromycin. The pLH-HygB-HuSHXG-GFP-HdSHXG was transformed into the protoplast of Mycena which then expressed GFP. The established protoplast transformation system of Mycena laid a foundation for analyzing the functional genes of Mycena and the molecular mechanism of the symbiosis of Mycena and G. elata.

Utilization of used fungus-growing materials of Gastrodia elata / 中国中药杂志

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.

Methyl jasmonate stimulates the synthesis and accumulation of asperosaponin VI in the roots of Dipsacus asper / 药学学报

We investigated the effect of methyl jasmonate (MeJA) on the content of asperosaponin VI and the expression of genes involved in its synthesis. Dipsacus aspero seedlings were treated with MeJA at different concentrations of 50, 100, 150, 200 and 300 μmol·L-1, and leaves and roots were sampled following treatment for 1, 3 and 5 days. The content of asperosaponin VI and superoxide anion in the roots, malondialdehyde (MDA) content in leaves and superoxide dismutase were determined. The results show that 150 μmol·L-1 MeJA significantly increased the accumulation of asperosaponin VI in roots. The content of asperosaponin VI was greatest after treatment for 3 days, and was 2.16 times higher than the control. After MeJA treatment, SOD activity decreased and MDA content increased in leaves. Moreover, superoxide anion content in roots increased. The expression of squalene epoxidase (DaSE1) and geranyl diphosphate synthase (DaGPS), key enzymes in the synthesis of asperosaponin VI, were up-regulated compared with the control group. These results indicate that an optimal concentration of 150 μmol·L-1 MeJA increases the accumulation of asperosaponin VI by up-regulating the expression of key enzymes involved in the synthesis of asperosaponin VI, which facilitates resistance to adversity stress stimulated by MeJA.

[Bletilla striata ecological planting patterns and technical principle analysis].

Bletilla striata is a shallow-rooted herbaceous plant, which is highly dependent on the planting environment.In order to improve the quality of B.striata effectively and solve the contradiction between the production of traditional Chinese medicine and the ecological environment, a variety of simulated cultivation patterns have been explored in various producing areas. Through field investigation and literature collation, this paper sorted out 24 sets of simulated cultivation modes of B.striata, including 4 kinds of sub-forest imitative wild planting techniques, 10 kinds of B.striata-economic forest cooperative development mode, 14 kinds of intercropping techniques of B.striata and 1 kind of ecological rotation technique of B.striata-edible fungi under economic forest. Combining economic benefit, social benefit and ecological benefit, the advantages and disadvantages of these planting patterns were compared. The ecological principles of B.striata simulative cultivation are analyzed in detail, as follows:(1) the wild cultivation of B.striata simulative cultivation under forest is to utilize the complementary principle of land resources under forest and spatial light and heat resources, and carry out the compound cultivation of cultivating forest with medicine and growing with short growth;(2) the intercropping of B.striata makes full use of the difference in height and height of the two plants to meet their needs for light, humidity and ventilation, reduce the cost of shading and weeding, improve the risk-resistant ability of Chinese medicinal materials cultivation, and increase the utilization rate of land, and give consideration to the benefits of both length and length;(3) the ecological rotation technology of "B.striata-edible fungi" in economic forests is to realize the effective utilization of waste bacteria and residues according to the mutually beneficial relationship between B.striata and edible fungi. The promotion and optimization of B.striata imitated wild cultivation technology will further promote the sustainable development of B.striata industry.