Impacts of soil environment on the growth and quality of Cynanchum auriculatum mediated by rhizosphere microorganisms

Abstract

The growth and quality of Cynanchum auriculatum is profoundly influenced by the soil environment, where multi-year cultivation leading to a reduction in growth potential and an increased susceptibility to diseases. Despite these impacts, there is a lack of comprehensive reports on how the soil environment specifically affects the growth and quality of C. auriculatum. In this study, we collected rhizosphere soil and root samples of C. auriculatum. We determined the soil composition, carbon metabolic capacity, and potential functions using metagenomic techniques, and analyzed the chemical constituents in the roots. We found that microbial metabolic capacity for phenolic acid carbon sources declined significantly in C. auriculatum rhizosphere soils from the third-year compared to the second-year. As planting years increased, the diversity of the rhizosphere soil bacterial community decreased. Bradyrhizobium and Lysobacter were identified as the dominant bacterial genera in the rhizosphere soil of C. auriculatum. The soil environmental factors influencing changes in bacterial and fungal communities in rhizosphere soil were identified as total nitrogen, available nitrogen, available phosphorus, available potassium, alkaline phosphatase, and catalase. These factors influenced the function of metabolic genes in rhizosphere microorganisms, leading to a decrease in metabolic activity and a disruption in the dynamic balance of microorganisms. Our research can provide a theoretical basis for enhancing the rhizosphere soil environment, optimizing management practices, and increasing the productivity and quality of C. auriculatum.