Rhizosphere Microecological Changes Associated with Etiolation of Fritillaria thunbergii Miq.: Impacts on Biomass and Active Components

Dried bulbs of Fritillaria thunbergii Miq. (Liliaceae family) are medicinal materials used to clear heat and resolve phlegm. However, premature plant etiolation during cultivation reduces yield and hampers the industrial development of these plants. This study compared agronomic traits, soil properties, enzyme activities, microbial communities, and metabolomic profiles between healthy and etiolated plants, in order to explore rhizosphere microecological changes. The results showed that etiolated plant biomass decreased by 57.58%. Although peimine and peiminine levels increased by 26.09% and 18.31%, respectively, total alkaloid accumulation decreased by 37.13%. In the rhizosphere soil of etiolated plants, total nitrogen and organic matter decreased, whereas invertase and urease activities increased. The rhizosphere of etiolated plants showed enrichment in microbial genera such as Clitopilus, which enhanced tryptophan and diterpenoid metabolism in the rhizosphere and plant tissues, increasing bioactive component content. Conversely, the decreased abundance of genera, including Bacillus, impaired isoflavone and tyrosine metabolism, reducing plant resistance. This study revealed correlations among rhizosphere microecology, plant etiolation, and variations in bioactive components, providing insights into improving the yield and quality of F thunbergii through rhizostheric regulation.