Multi-Omics Reveals a Coordinated Salt Tolerance Mechanism in Medicinal Plant Tussilago farfara

Salt stress affects not only the growth and development of medicinal plants but also their secondary metabolism and medicinal quality. In this study, we employed an integrative approach combining physiological assays with multi-omics analyses to systematically investigate the response mechanisms of Tussilago farfara L. to salt stress. The results showed that salt stress induced the accumulation of osmoprotectants and enhanced antioxidant enzyme activities, while significantly reshaping secondary metabolic pathways. Metabolomic analysis revealed differential response patterns of various compounds to salt stress: flavonoids and phenylpropanoids exhibited an initial increase followed by a decrease, whereas quinic acid esters and sesquiterpenoids continuously accumulated. Based on the accumulation trends of these compounds, 100 mM NaCl was identified as the most suitable concentration among the tested gradients for balancing medicinal component accumulation and basic plant growth, under which the most pronounced increase in medicinal components occurred. Transcriptomic analysis showed that under this suitable concentration, the flavonoid and phenylpropanoid biosynthesis pathways were strongly activated, with key structural genes significantly upregulated-a finding further validated by qRT PCR analysis. Correlation network analysis revealed that transcription factors from the AP2/ERF, WRKY, MYB, and NAC families exhibited significant associations with biosynthetic genes for these medicinal compounds, suggesting their potential involvement in the transcriptional regulation of active component accumulation under salt stress. This study would establish a foundation for elucidating the molecular mechanisms underlying salt tolerance and the formation of medicinal quality in T. farfara, and provide a potential strategy for improving its medicinal quality under saline-alkali conditions.