Mechanisms of pathogenic microorganisms, root antioxidant systems, and secondary metabolites of Codonopsis pilosula (Franch.) Nannf. in response to continuous cropping obstacles

作者：Ling Xu, Lei Ma, Guiping Chen, Ruonan Wei, Yantong Ma, Junhong Dang, Zhen Cheng, Shaoying Ma, Sheng Li · 发表于：Industrial Crops and Products · 年份：2025 · DOI：10.1016/j.indcrop.2025.120455 · 被引用次数：10 · 研究领域：Allelopathy and phytotoxic interactions、Plant-Microbe Interactions and Immunity、Plant Pathogens and Fungal Diseases

Understanding the mechanisms that give rise to obstacles in the continuous cultivation of C. pilosula is essential for addressing or mitigating these challenges. The findings of this study suggest that repeated cultivation significantly reduced the content of polysaccharide in roots, and significantly increased the dead seedling rate in the field. The vascular bundles of the affected plant were extensively colonized by fungi. Furthermore, the root vascular bundles exhibit significant woodiness and corkiness, accompanied by cellular fractures and structural collapse. It was determined that the pathogenic endophyte is Fusarium oxysporum , and the exacerbated disease manifestation corresponds to an acute wilting type. Additionally, the root-zone soil microorganisms Cladosporium austroafricanum , Fusarium foetens , Fusarium petersiae , and Acaulium retardatum may significantly contribute to the yield-reducing phenomenon associated with continuous cropping. The proliferation of pathogenic bacteria during continuous cultivation initiates a complex interaction mechanism between the host plant and these pathogens. This process is characterized by a rapid increase in calcium ion (Ca²⁺) concentration, which subsequently leads to an upsurge in reactive oxygen species (ROS), particularly manifested as elevated levels of hydrogen peroxide (H₂O₂). Additionally, this response triggers thickening of cell walls and other immune mechanisms aimed at inhibiting the invasion of pathogenic bacteri...