Effect of Continuous Cropping on Growth and Lobetyolin Synthesis of the Medicinal Plant Codonopsis pilosula (Franch.) Nannf. Based on the Integrated Analysis of Plant-Metabolite-Soil Factors

The integrated plant-metabolite-soil regulation model of C. Pilosula growth and lobetyolin synthesis in response to continuous cropping lacks systematic investigation. In this study, we investigated the regulatory mechanisms of growth and lobetyolin synthesis in C. pilosula under continuous cropping stress based on high-performance liquid chromatography, transcriptome, and microbial sequencing on the root system and rhizosphere soil of C. pilosula from one year of cultivation and five years of continuous cropping. The findings of this study revealed that continuous cropping significantly inhibited the growth of C. pilosula and led to a notable decrease in the lobetyolin content. An effort was made to propose a potential pathway for lobetyolin biosynthesis in C. pilosula, which is closely linked to the expression of genes responsible for glucoside and unsaturated fatty acid chain synthesis. In addition, soil physicochemical properties and soil microorganisms had strong correlations with root growth and synthesis of lobetyolin, suggesting that soil physicochemical properties and microorganisms are the main factors triggering the succession disorder in C. pilosula. This study provides an in-depth interpretation of the regulatory mechanism of acetylenic glycoside synthesis and offers new insights into the triggering mechanism of C. pilosula succession disorder, which will guide future cultivation and industrial development.