Comparative analysis of the rhizosphere microbiome and medicinally active ingredients of Atractylodes lancea from different geographical origins.

This study aimed to explore the important role of the rhizosphere microbiome in the quality of Atractylodes lancea (Thunb.) DC. (A. lancea). The rhizosphere microbial community of A. lancea at two sampling sites was studied using metagenomic technology. The results of α-diversity analysis showed that the rhizosphere microbial richness and diversity were higher in the Maoshan area. The higher abundance of core microorganisms of the rhizosphere, especially Penicillium and Streptomyces, in the Maoshan area compared with those in the Yingshan area might be an important factor affecting the yield of A. lancea. Redundancy analysis illustrated that the available phosphorus had a significant effect on the rhizosphere microbial community structure of A. lancea. We also showed that the plant-microbe and microbe-microbe interactions were closer in the Maoshan area than in the Yingshan area, and Streptomyces were the main contributors to the potential functional difference between the two regions. A. lancea in the Maoshan area had a high content of atractylodin and atractylon, which might be related to the enhanced abundance of Streptomyces, Candidatus-Solibacter, and Frankia. Taken together, this study provided theoretical insights into the interaction between medicinal plants and the rhizosphere microbiome and provides a valuable reference for studying beneficial microbes of A. lancea.

Effect of drought on photosynthesis, total antioxidant capacity, bioactive component accumulation, and the transcriptome of Atractylodes lancea.

BACKGROUND: Atractylodes lancea (Thunb.) DC, a medicinal herb belonging to the Asteraceae family, often faces severe drought stress during its growth. Until now, there has been no research on the effect of drought stress on the quality formation of A. lancea. Therefore, the present study aimed to study the effects of drought stress on A. lancea through physical and chemical analysis, and to reveal the related molecular mechanisms via transcriptome analysis. RESULTS: The photosynthesis was markedly inhibited under drought stress. There were alterations to photosynthetic parameters (Pn, Gs, Ci) and chlorophyll fluorescence (Fv/Fm, NPQ), and the chlorophyll content decreased. Twenty genes encoding important regulatory enzymes in light and dark reactions, including the Rubisco gene of the Calvin cycle, were significantly downregulated. After exposure to drought stress for more than 4 days, the activities of four antioxidative enzymes (SOD, POD CAT and APX) began to decrease and continued to decrease with longer stress exposure. Meanwhile, most of the genes encoding antioxidative enzymes were downregulated significantly. The downregulation of 21 genes related to the respiratory electron transport chain indicated that the blocked electron transfer accelerated excessive ROS. The MDA content was significantly elevated. The above data showed that 15 days of drought stress caused serious oxidative damage to A. lancea. Drought stress not only reduced the size and dry weight of A. lancea, but also lowered the amount of total volatile oil and the content of the main bioactive components. The total volatile oil and atractylodin content decreased slightly, whereas the content of atractylon and ß-eudesmol decreased significantly. Moreover, ten significantly downregulated genes encoding sesquiterpene synthase were mainly expressed in rhizomes. CONCLUSIONS: After exposed to drought stress, the process of assimilation was affected by the destruction of photosynthesis; stress tolerance was impaired because of the inhibition of the antioxidative enzyme system; and bioactive component biosynthesis was hindered by the downregulation of sesquiterpene synthase-related gene expression. All these had negative impacts on the quality formation of A. lancea under drought stress.

Metabolomics analysis of dandelions from different geographical regions in China.

INTRODUCTION: Dandelion (Taraxacum mongolicum Hand.-Mazz.) is a perennial herb with diverse pharmacological effects. The development and utilization of dandelion have attracted much attention. OBJECTIVES: Our aims were to provide a reference basis for the identification of the origin of dandelions and to study the influence of their origin on their quality. Methods High-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was used to analyze metabolites from dandelions from four different geographical regions in China, namely Gansu, Henan, Shanxi, and Jiangsu. Metabolite analysis was performed using orthogonal partial least-squares discriminant analysis, and to identify potential metabolic pathways, MBRole was used to perform Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. RESULTS: Principal component analysis revealed that the chemical components of dandelions sampled from the four regions showed noticeable differences. Twenty-six, six, six, eight, eight, and fifteen differentially produced metabolites were identified upon comparison between Gansu and Jiangsu, Gansu and Shanxi, Gansu and Henan, Henan and Shanxi, Henan and Jiangsu, and Shanxi and Jiangsu, respectively. These differentially produced metabolites were mainly phenolic compounds. Further, KEGG pathway enrichment analysis showed that the main metabolic pathways involved were biosynthesis of phenylpropanoids and flavonoids. CONCLUSION: The methods reported herein can be used to identify the origin of dandelions; moreover, our results can serve as a reference basis for future studies.