Application of UPLC-Orbitrap-HRMS targeted metabolomics in screening of allelochemicals and model plants of ginseng

Continuous cropping of ginseng leads to serious declines in yield and quality because of self-toxicity of alle-lochemicals and other factors in soil. However, because of the long growth cycle and low survival rate of ginseng, rapid screening of autotoxic activity is difficult. Therefore, it is important to analyze the allelochemicals and identify a model plant with autotoxic responses similar to those of ginseng. In this study, UPLC-Orbitrap-HRMS targeted metabolomics and verification of autotoxic activity were used to analyze a problem soil from contin-uously cropped ginseng. Allelochemical markers were screened by OPLS-DA. Seeds and seedlings of maize, Chinese cabbage, cucumber, green beans, wheat, sunflower, and oats were selected to identify potential model plants. Model plants with autotoxic responses similar to those of ginseng were evaluated by comparing morphological, physiological, and biochemical characteristics. The n-butanol extract of the continuously cropped problem soil had the most significant autotoxic activity. Twenty-three ginsenosides and the contributions to autotoxic effects were screened and evaluated. Of potential model plants, seeds and seedlings of cucumber showed similar growth inhibition to that of ginseng under the action of allelochemicals. Thus, metabolomics can be used to screen allelochemicals in soil and predict the autotoxic effects, and the cucumber plant model can be used to rapidly screen allelopathic activity of ginseng. The study will provide reference for methodology in allelopathy research on ginseng.

Automated summary

Continuous cropping of ginseng leads to a decline in yield and quality due to self-toxicity and other factors in the soil. It is difficult to rapidly screen autotoxic activity due to the long growth cycle and low survival rate of ginseng. This study analyzed a problem soil from continuously cropped ginseng using UPLC-Orbitrap-HRMS targeted metabolomics and autotoxic activity verification. Allelochemical markers were screened and a cucumber plant model with similar autotoxic responses to ginseng was identified. Metabolomics can be used to predict autotoxic effects in soil, and the cucumber plant model can rapidly screen allelopathic activity of ginseng.