Biochar reduces the cadmium content of Panax quinquefolium L. by improving rhizosphere microecology.

Cadmium (Cd) accumulation in American ginseng (Panax quinquefolium L.) can negatively impact its yield and safety. Our previous study found that biochar could reduce cadmium content of P. quinquefolius, however, the mechanism was yet to be elucidated. In the present study, we tested four treatments in order to reveal the mechanism by which this phenomenon occurs: control, Cd, Cd + biochar and biochar. The results showed that the following responses were induced by the addition of biochar under Cd stress. Firstly, the soil physicochemical properties were improved, this is especially true for the soil pH value and soil organic matter content, which were increased by 20.42 % and 15.57 %, respectively. Secondly, the relative abundances of several beneficial microorganism phyla; such as Proteobacteria, Bacteroidota and Actinobacteria; were increased by 10.69 %, 20.11 % and 60.86 %, respectively. Thirdly, treatment with biochar reduced the Cd content by increasing cadmium-chelated metabolites within the soil (e.g., naringenin, caffeic acid, and valine) and increasing detoxification substances in plants (e.g., malic acid, flavonoids, and fumaric acid). Changes in these metabolites were significantly correlated with rhizosphere microecology. In summary, biochar treatment reduced the Cd content in seedlings by improving the soil properties, rhizosphere community, soil metabolites, and plant metabolites.

[Resource components and utilization values of different parts of Panax quinquefolium in Shandong province].

To explore the resource components and availability of different parts of Panax quinquefolium in Shandong province, the paper employed the non-targeted metabolomics technology based on ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) to analyze the metabolites and their metabolic pathways in the root, fibril, stem, and leaf of P. quinquefolium. The content of seven ginsenosides and polysaccharides in different parts was determined by high performance liquid chromatography(HPLC) and ultraviolet-visible spectrophotometry(UV-Vis). The results showed that the metabolites were mainly sugars, glycosides, organic acids, amino acids and their derivatives, terpenoids, etc. The total abundance of metabolites followed the trend of leaf > root > fibril > stem. Most of the differential metabolites were concentrated in phenylpropane biosynthesis, flavonoid biosynthesis, citric acid cycle, and amino acid biosynthesis. The leaf contained high levels of sugars, glycosides, amino acids and their derivatives, and flavonoids; the root was rich in terpenoids, volatile oils, vitamins, and lignin; the fibril contained rich organic acids; and the stem had high content of nucleotides and their derivatives. The content of ginsenosides Re and Rb_1 was significantly higher in the root; the content of ginsenosides Rg_1, Rg_2, Rd, F_(11), and polysaccharide was significantly higher in the leaf; and the content of ginsenoside Rb_2 was significantly higher in the stem. We analyzed the resource components and availability of different parts of P. quinquefolium, aiming to provide basic information for the comprehensive development and utilization of P. quinquefolium resources in Shandong province.

Combinatorial transcriptomics and metabolomics analysis reveals the effects of the harvesting stages on the accumulation of phenylpropanoid metabolites in Lonicera japonica.

The flower buds of Lonicera japonica are widely used for its high medicinal value. It is reported that the accumulation of phenylpropanoids in the buds of L. japonica is affected by the stage at which it is harvested. However, the changes of active components and the underlying mechanisms in flower buds at different harvesting stages have not been reported. Integrative analyses of transcriptomics and metabolomics was used to explore the underlying mechanism of harvesting stages (green bud, GB; and white bud, WB) on the phenylpropanoids metabolites accumulation in L. japonica . The result showed that 3735 differentially expressed genes were identified, and the genes related to glycolysis/gluconeogenesis and phenylalanine biosynthesis pathway were significantly upregulated in GB stage. A total of 510 differential metabolites were identified in GB stage. Among them, 14 phenylpropanoids were changed during the GB and WB, seven of which increased in GB, including caffeic acid, sauchinone, coniferin, secoisolariciresinol diglucoside, scopolin, methyl cinnamate, chlorogenic acid, 7-hydroxycoumarin, while others such as sibiricose A6, coumarin, eleutheroside E decreased. Further correlation analysis showed that the unigenes for CSE, CAD, bg1, ADH, ALDH, DLAT and ENO significantly correlated with the 10 phenylpropanoid. The above results would provide basic data for the selection of harvesting stages in the production of L. japonica .

Diversity and correlation analysis of endophytes and metabolites of Panax quinquefolius L. in various tissues.

BACKGROUND: Panax quinquefolius L. (American ginseng) is widely used in medicine due to its wealth of diverse pharmacological effects. Endophytes colonize within P. quinquefolius in multiple tissue types. However, the relationship between endophytes and the production of their active ingredients in different parts of the plant is not clear. RESULTS: In this study, the relationship of endophytic diversity and the metabolites produced in different plant tissues of P. quinquefolius were analyzed using metagenomic and metabolomic approaches. The results showed relatively similar endophyte composition in roots and fibrils, but obvious differences between endophyte populations in stems and leaves. Species abundance analysis showed that at the phylum level, the dominant bacterial phylum was Cyanobacteria for roots, fibrils, stems and leaves, Ascomycota forroots and fibrils roots, and Basidiomycota for stems and leaves. LC-MS/MS technology was used to quantitatively analyze the metabolites in different tissues of P. quinquefolius. A total of 398 metabolites and 294 differential metaboliteswere identified, mainly organic acids, sugars, amino acids, polyphenols, and saponins. Most of the differential metabolites were enriched in metabolic pathways such as phenylpropane biosynthesis, flavonoid biosynthesis, citric acid cycle, and amino acid biosynthesis. Correlation analysis showed a positive and negative correlation between the endophytes and the differential metabolites. Conexibacter significantly enriched in root and fibril was significantly positively correlated with saponin differential metabolites, while cyberlindnera significantly enriched in stem and leaf was significantly negatively correlated with differential metabolites (p < 0.05). CONCLUSION: The endophytic communities diversity were relatively similar in the roots and fibrils of P. quinquefolius, while there were greater differences between the stems and leaves. There was significant difference in metabolite content between different tissues of P. quinquefolius. Correlation analysis methods demonstrated a correlation between endophytes and differential metabolism.

Transcriptomics and metabolomics reveal the changes induced by arbuscular mycorrhizal fungi in Panax quinquefolius L.

BACKGROUND: Panax quinquefolius L. is one of the most important foods and herbs because of its high nutritional value and medicinal potential. In our previous study we found that the ginsenoside content in P. quinquefolius was improved by arbuscular mycorrhizal fungi (AMFs). However, little research has been conducted on the molecular mechanisms in P. quinquefolius roots induced by AMFs colonization. To identify the metabolomic and transcriptomic mechanisms of P. quinquefolius induced by AMFs, non-mycorrhized (control) and mycorrhized (AMF) P. quinquefolius were used as experimental materials for comparative analysis of the transcriptome and metabolome. RESULTS: Compared with the control, 182 metabolites and 545 genes were significantly changed at the metabolic and transcriptional levels in AMFs treatment. The metabolic pattern of AMFs was changed, and the contents of ginsenosides (Rb1, Rg2), threonine, and glutaric acid were significantly increased. There were significant differences in the expression of genes involved in plant hormone signal transduction, glutathione metabolism, and the plant-pathogen interaction pathway. In addition, several transcription factors from the NAC, WRKY, and basic helix-loop-helix families were identified in AMFs versus the control. Furthermore, the combined analysis of 'transcriptomics-metabolomics' analysis showed that 'Plant hormone signal transduction', 'Amino sugar and nucleotide sugar metabolism' and 'Glutathione metabolism' pathways were the important enriched pathways in response to AMFs colonization. CONCLUSION: Overall, these results provide new insights into P. quinquefolius response to AMFs, which improve our understanding of the molecular mechanisms of P. quinquefolius induced by AMFs. © 2023 Society of Chemical Industry.

[Diversity of arbuscular mycorrhizal fungi of Panax quinquefolius cultivated in Shandong province].

In this study, the colonization, diversity and relative abundance of arbuscular mycorrhizal fungi(AMF) in the roots of Panax quinquefolius in different habitats of Shandong province were analyzed by staining-microscopy and high-throughput sequencing. The data were analyzed by bioinformatics tools and statistical software. The results showed that the roots of P. quinquefolius in different habitats were colonized by AMF with different rates and intensities. The AMF in roots of P. quinquefolius belong to three genera, three families, three orders, one class and one phylum. At the level of order, the AMF mainly included Paraglomerales(52.48%), Glomerales(25.60%) and Archaeosporales(3.08%). At the level of family, the AMF were dominated by Paraglomeraceae(52.48%), Glomeraceae(18.94%) and Claroideoglomeraceae(3.05%). At the level of genus, Paraglomus(51.46%), Glomus(20.01%) and Claroideoglomus(3.52%) accounted for a large proportion, of which Paraglomus and Glomus were dominant. Cluster analysis showed that the AMF in roots of P. quinquefolius with close geographical locations could be clustered together. In this study, the diversity and dominant germplasm resources of AMF in roots of P. quinquefolius cultivated in the main producing areas were identified, which provi-ded basic data for revealing the quality formation mechanism of P. quinquefolius medicinal materials from the perspective of environment.

[Research progress on application of biochar in cultivation of agriculture and Chinese materia medica].

Biochar is a kind of solid material with high aromatization and rich in carbon, which is formed by pyrolysis of biomass at high temperature(250-700 ℃) under anoxic or hypoxic conditions. It has the characteristics of large specific surface area and rich pores. In recent years, as a good soil conditioner, biochar has gradually improved its advantages in improving soil rhizosphere micro ecological environment, promoting plant growth and development, and enhancing plant resistance, etc. It has been proved that biochar can affect the growth and development of plants by improving soil physical and chemical properties, adjusting microbial community structure, participating in the metabolic process in plants, and inducing plants to enhance resistance. This paper summarized the research progress of biochar application in agriculture and introduced the ecological effects and mechanism of biochar on plant seed germination, seedling growth, crop yield and stress resistance. Combined with the characteristics of Chinese materia medica, this paper expounds the application potential of biochar in improving the content of secondary metabolites of Chinese materia medica and alleviating continuous cropping obstacles of Chinese materia medica, etc. In the future, it is necessary to strengthen the research of biochar in the biosynthesis of secondary metabolites, allelopathy and heavy metal stress of medicinal plants, so as to provide reference for the application of biochar in the cultivation of Chinese materia medica.

[Preliminary investigation on arbuscular mycorrhiza fungi of cultivated Panax quinquefolium roots].

In this study, the infection of root arbuscular mycorrhizal fungi(arbuscular mycorrhizal fungi, AMF of Panax quinquefolium in Shandong province was investigated, and the distribution characteristics and infection regularity of AMF were found out. The AMF of P. quinquefolium roots in different habitats was examined by alkali dissociation-trypickin blue staining method to study the infection rate and infection intensity. The contents of ginsenoside(Rb_1, Re, Rg_1, Rb_2, Rd and Rh_1) in the roots of P. quinquefolium was determined by HPLC. The experimental data were SPSS 17.0 statistical software for One-way analysis of variance, cluster analysis and correlation analysis. The results showed that the AMF infection in roots of P. quinquefolium, and there were obvious structures such as hyphae, arbuscular branches and vesicles, and the AMF infection rate and infection intensity showed obvious spatial and temporal heterogeneity with the growth age and origin of P. quinquefolium. The infection rate of AMF in roots of P. quinquefolium from 1 to 3 years increased significantly with the increase of growth years(P<0.05). The infection intensity and infection rate of P. quinquefolium showed a similar change trend, the AMF infection rate and infection intensity reached the highest level in the third year. Cluster analysis showed that the infection rates of roots of P. quinquefolium in similar geographical locations could be clustered together. Correlation analysis showed that the AMF infection rate of P. quinquefolium root was significantly positively correlated with the infection intensity, and the AMF infection rate and infection intensity were significantly positively correlated with the contents of ginsenoside Rg_1, Re and Rb_1. This study explored the distribution characteristics and regularity of AMF in roots of P. quinquefolium under the protected cultivation conditions, and provided basic data for ecological cultivation of P. quinquefolium and research and development of biological bacterial fertilizer.

Postharvest UV-B Irradiation Stimulated Ginsenoside Rg1 Biosynthesis through Nitric Oxide (NO) and Jasmonic Acid (JA) in Panax quinquefolius Roots.

The study highlights the influence and signal transduction mechanism of postharvest UV-B on the production of Rg1 in Panax quinquefolius roots during the drying process. The results showed that postharvest UV-B irradiation induced generation of nitric oxide (NO), jasmonic acid (JA), and ginsenoside Rg1 of P. quinquefolius roots. The UV-B-induced increase of Rg1 was suppressed by NO-specific scavenger (cPTIO) and NOS inhibitors (PBITU), JA synthesis inhibitor (SHAM), and JA synthesis inhibitor (PrGall), indicating that NO and JA played essential parts in UV-B-induced Rg1. External NO inhibitors treatment inhibited UV-B-induced accumulation of NO and JA, which suggested that NO was located upstream of the JA signal pathway. NO-caused Rg1 was inhibited by SHAM and PrGall, implying JA participated in transmitting signal NO to Rg1 accumulation. In other words, NO mediated the postharvest UV-B-induced Rg1 accumulation by the JA-dependent pathway in P. quinquefolius roots during the drying process, which helps us understand the underlying mechanisms involved in UV-B-induced Rg1 production and provides information helpful for P. quinquefolius production.