Effects of 2,4-Di‑tert-butylphenol treatment on the active constituents of Lilium brownii var. viridulum and its mechanism

• SOD, CAT, POD activities were elevated in L. brownii by high 2,4-DTBP treatment. • Contents of total phenols, flavonoids, saponins were increased in L. brownii by 2,4-DTBP stress. • Phenolics and flavonoids are essential metabolites for L. brownii to mitigate 2,4-DTBP stress. • 2,4-DTBP stimulated phenylpropanoid and flavonoid synthesis in L. brownii metabolism. Continuous cropping obstacles in Lilium brownii var. viridulum ( L. brownii ), a medicinal plant, are significantly influenced by autotoxicity, yet its impact on active components remains unexplored. This study investigates the effects of varying concentrations (0.02–2 mg mL -1 ) of the autotoxin 2,4-di‑tert-butylphenol (2,4-DTBP) on the active constituents of L. brownii bulbs across three developmental stages: initial bulb formation (May 7, Stage 1), mid-bulb formation (June 16, Stage 2), and maturity (July 21, Stage 3). High 2,4-DTBP concentrations (2 mg mL -1 ) enhanced reactive oxygen species (ROS) scavenging and increased total phenols, flavonoids, and saponins. Transcriptomic analysis revealed that 2,4-DTBP induced significant changes in gene expression in the phenylpropanoid and flavonoid biosynthesis pathways, with 76 and 26 DEGs in Stage 2, respectively, decreasing to 48 and 6 DEGs in Stage 3. Metabolomic profiling showed significant upregulation of phenolic and flavonoid compounds in Stage 2, with notable accumulation of dihydrocaffeic acid 3-O-glucuronide and typhaneoside. Correlation analysis identified 80 genes strongly associated with flavonoid metabolites. These findings elucidate the mechanisms underlying changes in L. brownii ’s active components under autotoxic stress, providing theoretical support for optimizing its cultivation and medicinal applications.