Sun Jin, Yang Jing, Zhao Shuyue, Yu Qian, Weng Lili, Xiao Chunping
School of Pharmaceutical Sciences, Changchun University of Chinese Medicine, Changchun, China.
Front Microbiol. 2023 Jul 20;14:1194224. doi: 10.3389/fmicb.2023.1194224. eCollection 2023.
Root exudates contain a complex array of primary and specialized metabolites that play important roles in plant growth due to their stimulatory and inhibitory activities that can select for specific microbes. In this study, we investigated the effects of different root exudate concentrations on the growth of ginseng ( C. A. Mey), ginsenoside levels, and soil fungal community composition and diversity. The results showed that low root exudate concentrations in the soil promoted ginseng rhizome biomass and ginsenoside levels (Rg1, Re, Rf, Rg2, Rb1, Ro, Rc, Rb2, Rb3, and Rd) in rhizomes. However, the rhizome biomass and ginsenoside levels gradually decreased with further increases in the root exudate concentration. sequencing showed that low root exudate concentrations in the soil hardly altered the rhizosphere fungal community structure. High root exudate concentrations altered the structure, involving microecological imbalance, with reduced abundances of potentially beneficial fungi (such as ) and increased abundances of potentially pathogenic fungi (such as ). Correlation analysis showed that rhizome biomass and ginsenoside levels were significantly positively correlated with the abundances of potentially beneficial fungi, while the opposite was true for potentially pathogenic fungi. Overall, low root exudate concentrations promote the growth and development of ginseng; high root exudate concentrations lead to an imbalance in the rhizosphere fungal community of ginseng and reduce the plant's adaptability. This may be an important factor in the reduced ginseng yield and quality and soil sickness when ginseng is grown continuously.
根系分泌物包含一系列复杂的初级和特殊代谢产物，这些代谢产物因其刺激和抑制活性在植物生长中发挥重要作用，能够选择特定的微生物。在本研究中，我们调查了不同浓度的根系分泌物对人参（C. A. Mey）生长、人参皂苷水平以及土壤真菌群落组成和多样性的影响。结果表明，土壤中低浓度的根系分泌物促进了人参根茎生物量和根茎中人参皂苷水平（Rg1、Re、Rf、Rg2、Rb1、Ro、Rc、Rb2、Rb3和Rd）的增加。然而，随着根系分泌物浓度的进一步增加，根茎生物量和人参皂苷水平逐渐下降。测序结果表明，土壤中低浓度的根系分泌物几乎不会改变根际真菌群落结构。高浓度的根系分泌物会改变结构，导致微生态失衡，潜在有益真菌（如 ）的丰度降低，而潜在致病真菌（如 ）的丰度增加。相关性分析表明，根茎生物量和人参皂苷水平与潜在有益真菌的丰度显著正相关，而与潜在致病真菌的情况相反。总体而言，低浓度的根系分泌物促进人参的生长发育；高浓度的根系分泌物会导致人参根际真菌群落失衡，降低植物的适应性。这可能是人参连作时产量和品质下降以及出现土壤病害的一个重要因素。
