Root exudates contain a complex array of primary and specialized metabolites that play important roles in plant growth due to their stimulatory and inhibitory activities that can select for specific microbes. In this study, we investigated the effects of different root exudate concentrations on the growth of ginseng (Panax ginseng C. A. Mey), ginsenoside levels, and soil fungal community composition and diversity. The results showed that low root exudate concentrations in the soil promoted ginseng rhizome biomass and ginsenoside levels (Rg1, Re, Rf, Rg2, Rb1, Ro, Rc, Rb2, Rb3, and Rd) in rhizomes. However, the rhizome biomass and ginsenoside levels gradually decreased with further increases in the root exudate concentration. ITS sequencing showed that low root exudate concentrations in the soil hardly altered the rhizosphere fungal community structure. High root exudate concentrations altered the structure, involving microecological imbalance, with reduced abundances of potentially beneficial fungi (such as Mortierella) and increased abundances of potentially pathogenic fungi (such as Fusarium). Correlation analysis showed that rhizome biomass and ginsenoside levels were significantly positively correlated with the abundances of potentially beneficial fungi, while the opposite was true for potentially pathogenic fungi. Overall, low root exudate concentrations promote the growth and development of ginseng; high root exudate concentrations lead to an imbalance in the rhizosphere fungal community of ginseng and reduce the plant’s adaptability. This may be an important factor in the reduced ginseng yield and quality and soil sickness when ginseng is grown continuously.

Soil microorganisms affect crop rhizospheres via the transformation and transport of nutrients, which has important influences on soil fertility, carbon sequestration, and plant yield and health in agroecosystems. There are few reports on the effects of fertilizer application on the growth of Panax ginseng (C. A. Mey.) or the structure of its rhizosphere microbial communities. In this study, an orthogonal experimental design was used to explore the effects of nine different combinations of nitrogen (N), phosphorus (P), and potassium (K) fertilizers with different amounts and proportions on ginseng growth and accumulation of ginsenosides and the structure of rhizosphere soil fungal communities. Soil without fertilization was the control. With the combined application of NPK, ginseng growth and development increased. The fertilization scheme N₃P₁K₃, with N fertilizer at 50 g·m⁻², P fertilizer at 15 g·m⁻², and K fertilizer at 60 g·m⁻², had the most comprehensive benefit and significantly increased ginseng rhizome biomass and ginsenoside contents (Rg1, Re, Rf, Rg2, Rb1, Ro, Rc, Rb2, Rb3, and Rd). Amplicon sequencing showed that NPK application increased the diversity of fungal communities in ginseng rhizospheres, whereas richness was bidirectionally regulated by proportions and amounts of NPK. Ascomycota was the dominant fungal phylum in ginseng rhizosphere soil, and relative abundances decreased with combined NPK application. Combined NPK application increased the relative abundance of potential beneficial fungi, such as Mortierella, but decreased that of potentially pathogenic fungi, such as Fusarium. Correlation analysis showed that potential beneficial fungi were significantly positively correlated with ginseng rhizome yield and ginsenoside contents, whereas the opposite relation was observed with potential pathogenic fungi. Thus, in addition to directly increasing crop growth, precise NPK application can also increase crop adaptability to the environment by shaping specific microbial communities. The results of this study suggest that the combined effects of biotic and abiotic processes on agricultural production determine crop yield and quality.

In the planting of crops, especially medicinal plants, formula fertilization is important for improving the utilization rate of elements, soil quality, crop yield, and quality. Therefore, it is important to study targeted fertilizer application schemes for sustainable agricultural development and environmental protection. In this study, an L₉(3⁴) orthogonal design was used to conduct a field experiment to study the effects of NPK combined application on the growth and pharmacodynamic component biosynthesis of Atractylodes chinensis (DC.) Koidz. Results showed that after applying a base fertilizer at the seedling stage (late May), topdressing at the vegetative stage (late June) and fruit stage (late August) was beneficial to the growth and development of A. chinensis. The high concentrations of phosphorus were conducive to the accumulation of yield and effective components, and the best harvest time was after late October. Principal component analysis (PCA) showed that the comprehensive score of T6 treatment was the highest, indicating that the optimal fertilization scheme for the high yield and high quality of A. chinensis was (N₂P₃K₁): N 180, P₂O₅ 225, and K₂O 105 kg⋅ha^–1. A signaling response analysis showed that during the growth and development of A. chinensis, the T6 fertilization scheme had clear effects on the activity and gene expression of the key enzymes acetyl-CoA carboxylase (ACC) and farnesyl pyrophosphate synthase (FPPS). Under the T4 [(N₂P₁K₂): N 180, P₂O₅ 75, and K₂O 210 kg⋅ha^–1] fertilization scheme, the activity and gene expression of the key enzyme 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) were higher. Moreover, ACC was closely related to the synthesis of the polyacetylene component atractylodin, and FPPS played an important regulatory role in the synthesis of sesquiterpene components atractylenolide II, β-eudesmol, and atractylon. In summary, the high phosphorus fertilization scheme T6 could notably increase the yield of A. chinensis, and promote the accumulation of polyacetylene and sesquiterpene volatile oils by increasing the expression of ACC and FPPS. Therefore, we postulate that the precise application of nutrients (NPK) plays a vital role in the yield formation and quality regulation of A. chinensis.

Objective: The incidence of non-alcoholic fatty liver disease is increasing every year, and there is growing evidence that metabolites and intestinal bacteria play a causal role in NAFLD. Gentiopicroside, a major iridoids compound in gentian, has been reported to reduce hepatic lipid accumulation. However to date, no studies have confirmed whether the predominance of Gentiopicroside is related to metabolites and intestinal bacteria. Therefore, we sought to study whether the hypolipidemic effect of Gentiopicroside is related to metabolic function and intestinal flora regulation.Methods: In the present study, C57BL/6J mice were fed a high-fat diet for 12 weeks, followed by a high-fat diet with or without Gentiopicroside for 8 weeks, respectively. The Gentiopicroside intervention reduced body weight gain, liver index, and decreased serum biochemical parameters such as alanine aminotransferase, aspartate aminotransferase, and triglycerides in high-fat fed mice. The effect of Gentiopicroside on non-alcoholic fatty liver disease was studied using serum untargeted metabolomics and 16S rDNA assay.Results: Metabolomic analysis showed that the addition of Gentiopicroside significantly altered the levels of amino acids, unmetabolized Gentiopicroside after administration, and metabolites such as Cinnoline, Galabiosylceramide, and Tryptophyl-Tyrosine, which are involved in the pathways regulating bile secretion, tryptophan metabolism, and lipid metabolism. Analysis of intestinal bacteria showed that Gentiopicrosides altered the community composition structure of intestinal bacteria, characterized by an increase and a decrease in beneficial and harmful bacteria, respectively. In addition, correlation analysis showed that the effect of Gentiopicroside on metabolites was positively correlated with intestinal flora Bacteroides, Lactobacillus, Muribaculum, and Prevotellaceae_UCG_001. Finally, the combined analysis revealed that metabolites were associated with the regulation of Firmicutes and Actinobacteria and positively correlated with lipid levels.Conclusion: These results suggest that Gentiopicroside may be a potential agent for the prevention of intestinal disorders and the alleviation of non-alcoholic fatty liver disease.

Background. Spleen deficiency diarrhea (SDD) is a common Traditional Chinese Medicine (TCM) gastrointestinal condition, the causes of which include dysfunction of the intestinal barrier and microbiota. Rice water-fried Atractylodis Rhizoma (RAR) is a commonly used drug to treat this condition, but its mechanism remains unclear. This study explored the related mechanisms of ethanolic extract of rice water-fried Atractylodis Rhizoma (EAR) in the treatment of SDD by examining changes in the intestinal microbiota. Method. Wistar rats were randomly divided into 4 groups including the control, model, EAR low, and high-dose groups, 6 rats in each group. All rats, except the control group, were induced to develop SDD by a bitter-cold purgation method with rhubarb. The therapeutic effect of EAR on SDD was evaluated by pathological sections, inflammatory indicators (TNF-α, IL-1β, and IL-10), gastrointestinal-related indicators (GAS, DAO, D-lactate, VIP, and SIgA), and intestinal flora (bacteria and fungi) analysis. Results. The results showed that the developed SDD rat model (model group) showed weight loss, decreased food intake, and increased fecal moisture content. Compared with those of the control group, the levels of TNF-α, IL-1β, DAO, D-lactate, and VIP in the model group were significantly increased, but the levels of IL-10, GAS and SIgA were significantly decreased ( ). However, the indicators were significantly improved after EAR treatment, indicating that EAR maintained the balance of pro- and anti-inflammatory cytokines and reduced gastric emptying, thereby protecting intestinal barrier function, alleviating intestinal mucosal injury, and relieving SDD by regulating the release of neurotransmitters. EAR was also shown to prevent infection by promoting the accumulation of noninflammatory immunoglobulin SIgA and improving intestinal mucosal immunity to inhibit the adhesion of bacteria, viruses, and other pathogens. Intestinal microbiome analysis showed that the intestinal bacteria and fungi of SDD model rats changed greatly compared with the control group, resulting in intestinal microecological imbalance. The reversal in the composition of the flora after EAR treatment was mainly characterized by a large enrichment of beneficial bacteria represented by Lactobacillus and a decrease in the abundance of potentially pathogenic fungi represented by Aspergillus. Thus, it was speculated that EAR primarily functions to alleviate SDD by increasing the abundance of beneficial bacteria and reducing the abundance of potentially pathogenic fungi. Conclusion. The strong therapeutic effect of EAR on SDD suggests that it is a promising treatment for this condition.