Revealing the impact of the environment on the ginsenosides in American ginseng from three scales: bioclimatic factors, soil physicochemical properties and microbial communities

The environment exerts a significant impact on the growth and ingredients of plants. However, comprehensive studies are limited from multiple scales to reveal the influence of environmental factors on the ginsenosides in American ginseng. Here, bioclimatic factors, soil physicochemical properties and microbial communities were integrated to uncover the important factors affecting the ginsenosides in American ginseng. The contents of ginsenosides in American ginseng from the three major producing areas in China, namely Shandong, Beijing and Jilin were significantly different. From the microbial communities perspective, there were significant differences in soil microbial communities of American ginseng from the three major producing areas by 16S rRNA and ITS amplicon sequencing. The biomarkers, namely, Burkholderia (SDS), RB41 (BJS) and Bacillus (JLS), which can distinguish three geographical regions microbial communities, were identified by LEfSe and ternary plots. The functions profile of soil microbiome communities in SDS and BJS are differed from those in JLS. RDA analyses of bioclimatic factors, soil physicochemical properties, biomarker microbiomes and main ginsenosides content in American ginseng revealed that mean diurnal temperature range were the important factors affecting the variation of ginsenosides in American ginseng, with interpretation rates of 86.2%. The validation experiment showed that the mean diurnal temperature range of 25℃/25℃considerably increased total ginsenosides content compared with 25℃ /15℃ and 25℃/5℃. These results not only provide a theoretical basis for the subsequent mining of microbial functions and the study of biological fertilizers but also the utilization of mean diurnal temperature range for cultivation of high-quality medicinal plants.