School of Geography, Nanjing Normal University, Nanjing, China.
Yunnan Research Center of Biogas Technology and Engineering, College of Energy and Environment Science, Yunnan Normal University, Kunming, China.
Appl Environ Microbiol. 2020 Apr 17;86(9). doi: 10.1128/AEM.00130-20.
Autotoxic ginsenosides have been implicated as one of the major causes for replant failure of Sanqi ginseng (); however, the impact of autotoxic ginsenosides on the fungal microbiome, especially on soilborne fungal pathogens, remains poorly understood. In this study, we aimed to investigate the influence of the ginsenoside monomers Rg, Rb, and Rh, and that of their mixture (Mix), on the composition and diversity of the soil fungal community, as well as on the abundance and growth of the soilborne pathogen in pure culture. The addition of autotoxic ginsenosides altered the composition of the total fungal microbiome, as well as the taxa within the shared and unique treatment-based components, but did not alter alpha diversity (α-diversity). In particular, autotoxic ginsenosides enriched potentially pathogenic taxa, such as , , , , and , and decreased the abundances of beneficial taxa such as , , and Relative abundances of pathogenic taxa were significantly and negatively correlated with those of beneficial taxa. Among the pathogenic fungi, the genus was most responsive to ginsenoside addition, with the abundance of consistently enhanced in the ginsenoside-treated soils. Validation tests confirmed that autotoxic ginsenosides promoted mycelial growth and conidial germination of the root rot pathogen In addition, the autotoxic ginsenoside mixture exhibited synergistic effects on pathogen proliferation. Collectively, these results highlight that autotoxic ginsenosides are capable of disrupting the equilibrium of fungal microbiomes through the stimulation of potential soilborne pathogens, which presents a significant hurdle in remediating replant failure of Sanqi ginseng. Sanqi ginseng [ (Burk.) F. H. Chen] is geoauthentically produced in a restricted area of southwest China, and successful replanting requires a rotation cycle of more than 15 to 30 years. The increasing demand for Sanqi ginseng and diminishing arable land resources drive farmers to employ consecutive monoculture systems. Replant failure has severely threatened the sustainable production of Sanqi ginseng and causes great economic losses annually. Worse still, the acreage and severity of replant failure are increased yearly, which may destroy the Sanqi ginseng industry in the near future. The significance of this work is to decipher the mechanism of how autotoxic ginsenosides promote the accumulation of soilborne pathogens and disrupt the equilibrium of soil fungal microbiomes. This result may help us to develop effective approaches to successfully conquer the replant failure of Sanqi ginseng.
自毒人参皂苷被认为是三七人参（）重茬失败的主要原因之一；然而，自毒人参皂苷对真菌微生物组的影响，特别是对土壤病原真菌的影响，仍知之甚少。在这项研究中，我们旨在研究人参皂苷单体 Rg、Rb 和 Rh 及其混合物（Mix）对土壤真菌群落组成和多样性的影响，以及对纯培养土壤病原菌生长的影响。自毒人参皂苷的添加改变了总真菌微生物组的组成，以及共享和基于处理的成分中的分类群，但没有改变 α 多样性（α-多样性）。特别是，自毒人参皂苷富集了潜在的病原分类群，如 、 、 、 、 和 ，并降低了有益分类群的丰度，如 、 、和 。病原真菌的相对丰度与有益真菌的相对丰度呈显著负相关。在病原真菌中，属对人参皂苷的添加最为敏感，在人参皂苷处理的土壤中， 的丰度始终增加。验证试验证实，自毒人参皂苷促进了根腐病病原菌的菌丝生长和分生孢子萌发。此外，自毒人参皂苷混合物对病原菌的增殖表现出协同作用。总的来说，这些结果表明，自毒人参皂苷通过刺激潜在的土壤病原真菌，能够破坏真菌微生物组的平衡，这在修复三七人参重茬失败方面是一个重大障碍。三七人参[（Burk.）F.H.陈]原产于中国西南地区的一个特定地区，成功的再植需要 15 到 30 年以上的轮作周期。对三七人参的需求不断增加，耕地资源不断减少，促使农民采用连续的单一种植系统。再植失败严重威胁着三七人参的可持续生产，并造成每年巨大的经济损失。更糟糕的是，再植失败的面积和严重程度逐年增加，这可能在不久的将来摧毁三七人参产业。这项工作的意义在于揭示自毒人参皂苷促进土壤病原真菌积累和破坏土壤真菌微生物组平衡的机制。这一结果可能有助于我们开发有效的方法来成功克服三七人参的再植失败。
