Analysis of Lignan Content and Rhizosphere Microbial Diversity of Schisandra chinensis (Turcz.) Baill. Resources

Genetic and environmental factors influence the growth and quality of medicinal plants. In recent years, rhizosphere microorganisms have also emerged as significant factors affecting the quality of medicinal plants. This study aimed to identify Schisandra resources with high lignan content and analyze the microbial diversity of the rhizosphere soil. High-performance liquid chromatography was used to measure the lignan content in nine Schisandra fruits. High-throughput sequencing was used to analyze the 16S rDNA sequences of rhizosphere bacteria to identify bacterial species diversity. The total lignan content of the nine Schisandra resources ranged from 9.726 mg/g to 14.031 mg/g, with ZJ27 having the highest content and ZJ25 the lowest. Among the six lignan components, Schisandrol A had the highest content, ranging from 5.133 mg/g to 6.345 mg/g, with a significant difference between ZJ25, ZJ27, and other resources (p < 0.05). Schizandrin C had the lowest content, ranging from 0.062 mg/g to 0.419 mg/g, with more significant differences among the resources. A total of 903,933 sequences were obtained from the rhizosphere soil of the nine Schisandra resources, clustered into 10,437 OTUs at a 97% similarity level. The dominant bacterial phyla were Actinobacteriota, Acidobacteriota, Proteobacteria, Chloroflexi, Gemmatimonadota, and Verrucomicrobiota. The dominant bacterial genera were Candidatus_Udaeobacter, Candidatus_Solibacter, RB41, Bradyrhizobium, Gaiella, and Arthrobacter. ZJ27 is the Schisandra resource with the highest lignan content, and the rhizosphere bacteria of Schisandra are rich in diversity. Schisandra B is negatively correlated with Bryobacter, Candidatus_Solibacter, and unnamed genera of Gaiellales.