Longitudinal Distribution Map of the Active Components and Endophytic Fungi in Angelica sinensis (Oliv.) Diels Root and Their Potential Correlations

Abstract

The three distinct medicinal parts of Angelica sinensis (Oliv.) Diels (Ang) roots are the head, body, and tail (ARH, ARB, and ART, respectively). How endophytic fungi shape the differences in metabolic components among these parts remains unclear. We quantified the distribution of active components and endophytic fungi along the ARH, ARB, and ART and their relationships. Based on the metabolic components and their abundances detected via non-target metabolism, the different medicinal parts were distinguishable. The largest number of dominant metabolic components was present in ART. The difference between ART and ARH was the greatest, and ARB was in a transitional state. The dominant active molecules in ART highlight their effects in haemodynamics improvement, antibacterial, anti-inflammatory, and hormone regulation, while ARH and ARB indicated more haemostasis, blood enrichment, neuromodulation, neuroprotection and tranquilisation, hepatoprotection, and antitumour activities than that of ART. The ARHs, ARBs, and ARTs can also be distinguished from each other based on the endophytic fungi at the microbiome level. The most dominant endophytic fungi were distributed in ART; the differences between ART and ARH were the largest, and ARB was in a transition state, which is consistent with the metabolite distributions. Structural equation modelling showed that the endophytic fungi were highly indicative of the metabolic components. Correlation analysis further identified the endophytic fungi significantly positively correlated with important active components, including Condenascus tortuosus, Sodiomyces alcalophilus, and Pleotrichocladium opacum. The bidirectional multivariate interactions between endophytic fungi and the metabolic components shape their spatial variations along the longitudinal direction in the Ang root.

Keywords: Chinese Angelica; active metabolic components; association analysis; different medicinal parts; endophytic fungal communities; spatial variations.

Figure 1

Sampling and system stability of the metabonomic determination for Ang root and the discrimination of different medicinal parts based on the results. (a) Morphological divisions in the different medicinal parts of Ang root indicate the sample collection areas for the different parts. (b) Peaks of all QC sample outputs determined using the LC-MS system (positive ion mode) almost overlap, indicating the stability of the system; c and d, PCA and clustering of samples from different medicinal parts based on metabolite abundance data obtained from the positive (c) and negative (d) ion models.

Figure 2

Analysis of the differential metabolites between pairs of medicinal parts in Ang root (ARH vs. ART, ARH vs. ARB, and ART vs. ARB) under a positive ion mode. (a) Venn diagram showing the differential metabolites obtained by pairwise comparison; (b) categorical distributions of the differential metabolites in the pairwise comparisons; (c) hierarchical clustering of samples from different medicinal parts based on the abundance data for the differential metabolites.

Figure 3

Dominant metabolites (positive ion mode) and corresponding medicinal efficacy patterns in different medicinal parts of Ang root. (a,b) The top metabolites in ART have higher contents than those in both ARH and ARB, and an analysis of their medicinal efficacy patterns. (c,d) Top metabolites in both ARH and ARB with higher contents than those in ART and an analysis of their medicinal efficacy patterns. The *, **, and *** denote p < 0.1, <0.05 and <0.01, respectively.

Figure 4

KEGG enrichment analysis of the differential metabolites (positive ion mode) obtained from the different medicinal parts. (a–c) correspond to ARH vs. ART, ARH vs. ARB, and ART vs. ARB, respectively.

Figure 5

Top endophytic fungi in Ang root with high abundance. (a) Phylogenetic analysis at the genus level; (b) composition analysis at the genus level; and (c) compositional analysis at the species level.

Figure 6

Differential endophytic fungi in the various medicinal parts of Ang root and their distribution characteristics. (a) Venn diagram showing the OTUs of the endophytic fungi obtained from the different medicinal parts; (b) PCA and clustering of the samples from the three medicinal parts based on the abundance data for the endophytic fungi; (c) hierarchical cluster analysis of the samples from the three medicinal parts based on the abundance data for endophytic fungi at the genus level.

Figure 7

Pearson correlation analysis of the differential metabolites (positive ion mode) and endophytic fungi (species level) based on variations among the different medicinal parts of Ang root. *, **, and *** represent significance levels of 0.1, 0.05, and 0.01, respectively.

Figure 8

Structural equation model for the endophytic fungi (species level) and metabolites (positive ion mode) based on the differences among the medicinal parts of Ang root. The green bar chart shows the indication values for the differential species to the microbial module; the red-blue colour gradation shows the indicator values for the differential metabolite clusters to the metabolite module.