Changes of Key Soil Factors, Biochemistry and Bacterial Species Composition during Seasons in the Rhizosphere and Roots of Codonopsis pilosula (tangshen)

Abstract

Codonopsis pilosula is a medicinal and edible herb with a rich nutritional value. In Gansu Province, China, its production quality and yield differ during the four seasons. Here, we investigated the differences in the microfloral composition and metabolic functions in the rhizospheric soil and roots of C. pilosula during the four seasons, and we also analyzed their dynamic and synergistic effects on C. pilosula growth and carbohydrate content change. The C. pilosula samples were analyzed for plant physiology, microfloral composition and metabolic functions in the rhizospheric soil and roots using high-throughput sequencing technology. Environmental indices including soil physiochemistry and meteorological conditions were also determined by the coupled chromatography–spectroscopy technique. The results revealed that the C. pilosula growth was affected by temperature, precipitation and light intensity, with the bacterial structures and functions of the soil and root samples showing obvious seasonal changes. Due to the diversity of microbial composition and community metabolic function, and the synergistic effect of microbial and environmental factors, there are significant differences in stress resistance, physiological status and metabolites of C. pilosula in different seasons. Furthermore, the change in seasons was significantly correlated with the quality and yield of C. pilosula. This study provides a scientific basis for soil improvement and the refinement of local Radix C. pilosula cultivation methods.