Allelochemicals of Atractylodes lancea: Toxicity, plant response signaling, and natural fallow degradation

Allelochemicals, released by crop roots, frequently cause pathogen invasion and suffer losses due to their potential hazards to plant growth and soil microenvironment. Natural fallow received prominent attention in tackling agroecological problems and soil bioremediation. In this study, we employed Atractylodes lancea as a model to carried out the field experiments from 2015 to 2023 , and determine the toxicity of the allelochemicals and evaluated the responses of A. lancea using metabolomics, transcriptomics, and physiological indicators. The results showed that the allelochemicals accumulated after continuous cropping which leaded to soil acidification, imbalance of the soil microenvironment, and decrease in organic matter, the biomass and active components content of A. lancea , which also had a certain enrichment effect on harmful bacterial and fungal communities, such as Acidobacteria and Fusarium , further exacerbating the occurrence of soil borne diseases. Transcriptomics analysis revealed that allelochemicals inhibited plant TCA cycle, photosynthesis, terpenoid synthesis, and plant hormone signal transduction. Natural fallow experiment suggested that the soil fallowed naturally for 3 years showed that 2,4-di-tert-butylphenol content, soil pH, enzyme activities, and microbiota communities had no significant difference from that of control, indicating the recovery of the continuous cropping soils and could meet the requirements for replanting. Overall, this study revealed the toxicity of the allelochemicals and the molecular mechanisms of their growth inhibition effects in A. lancea , and provided an environment-friendly approach with low cost and high efficiency to allelochemicals degradation and soil bioremediation.