Diversity and spatiotemporal dynamics of fungal communities in the rhizosphere soil of Lycium barbarum L.: a new insight into the mechanism of geoherb formation

Abstract

Lycium barbarum L. is a well-known traditional geoherb in Ningxia, China. The fruits of L. barbarum contain several dietary constituents, and thus, they exert many beneficial effects on human health. However, a few studies have been conducted on the geoherb L. barbarum and its rhizosphere soil fungal community. In this study, we determined the physicochemical properties and fungal community structure of rhizosphere soil of L. barbarum from three regions of China, namely Ningxia (NX), Qinghai (QH), and Xinjiang (XJ), during three development stages of L. barbarum. Soil pH varied between 7.56 and 8.60 across the three regions, indicating that alkaline soil is conducive to the growth of L. barbarum. The majority of soil properties in NX, an authentic geoherb-producing area, were substantially inferior to those in XJ and QH during all three developmental stages. Total sugar, polysaccharide (LBP), and flavonoid contents were the highest in wolfberry fruits from NX. High-throughput sequencing showed that the abundance of the soil fungal population in NX was higher than that in QH and XJ during the flowering and fruiting stage and summer dormant stage. Moreover, the soil fungal diversity increased with the development of wolfberry. Ascomycota and Mortierellomycota were the predominant phyla in the rhizosphere fungal communities in all samples. Redundancy analysis showed a significant correlation of the soil-available phosphorus and LBP of wolfberry fruits with the fungal community composition. The characteristics of rhizosphere fungal communities determined in the present study provide insights into the mechanism of geoherb formation in NX wolfberry.

Keywords: Fungal community diversity; Geoherbs; Lycium barbarum L.; Rhizosphere soil.

Fig. 1

a The fungal community composition in the rhizosphere soil of different regions and during different developmental stages. NMDS plots of fungal communities based on Bray–Curtis distances; b the relative abundance of soil fungi in each sample at the phylum level

Fig. 2

RDA plot depicting the correlation between soil properties and fungal communities in three wolfberry production regions during the three developmental stages. a–c Samples from Ningxia (NX), Qinghai (QH), and Xinjiang (XJ) in the sprouting stage (SS), flowering and fruiting stage (FFS), and summer dormant stage (SDS); d, e samples from three wolfberry production regions in the SS, FFS and SDS

Fig. 3

The correspondence analysis for main active ingredients and fungal diversity of rhizosphere soils in three wolfberry production regions