Differences in the root-associated endophytic fungal community
composition and structure of three medicinal licorices in Xinjiang,
China
Abstract
Endophytic fungi have played a very important role in influencing the
quality and quantity of bioactive compounds of medicinal plants through
specific fungus-host interactions. In medicinal licorices root, a total
of 2,118,633 effective sequences and 1,063 effective operational
taxonomic units (OTUs) with 97% identity were obtained by
high-throughput sequencing. A total of 8 phyla and 140 genera were
annotated, among them, the phylum Ascomycota and Basidiomycota, and the
genera Fusarium, Paraphoma and Helminthosporium were significantly
dominant. Moreover, Wilcoxon rank sum test showed that the Shannon index
was significantly different distribution between Glycyrrhiza uralensis
and Glycyrrhiza inflata, especially 0-20cm at the root depth, the Chao1
index in Glycyrrhiza inflata was significantly affected by root depth,
and there were significant differences in beta diversity between
Glycyrrhiza uralensis and Glycyrrhiza inflata. Moreover, we explored the
content of bioactive compounds (glycyrrhizic acid, liquiritin and total
flavonoids) in roots of medicinal licorices based on high-performance
liquid chromatography. Our results showed that the liquiritin content
was not affected by the root depth (0-20cm, 20-40cm and 40-60cm), but
was significantly affected by the main effect species (Glycyrrhiza
uralensis, Glycyrrhiza inflata, Glycyrrhiza glabra) (P <
0.05), and the content of liquiritin was accountable for the differences
in the diversity of endophytic fungal community. Furthermore,
distance-based redundancy analysis (db-RDA) showed that soil
physicochemical properties (available potassium and ammonium nitrogen),
and the root factor (liquiritin and water content) were the main
contributing factors to the variations in the overall structure of
endophytic fungal community in this study.