Spatial metabolomics reveals brassinosteroid-mediated compartmentalization of saikosaponin biosynthesis in Bupleurum chinense DC. under abiotic stress.

Exogenous brassinosteroids enhance saikosaponin biosynthesis and alter spatial metabolite distribution in Bupleurum chinense under drought and salinity stress.

• Why it matters: Understanding how plant hormones coordinate stress resilience with secondary metabolite production is crucial for improving medicinal plant cultivation and stress adaptation strategies.
• What they did: The study applied 0.2 mg/L brassinosteroids to B. chinense seedlings exposed to drought, salinity, and combined stresses, then evaluated plant growth, membrane integrity, antioxidant activity, gene expression, and spatial metabolomics using MALDI-MSI.
• The result: BRs counteracted membrane damage, increased saikosaponin levels via gene activation under single stresses, but failed to do so under combined stress, revealing spatial compartmentalization and trade-offs in metabolic responses.