Light-induced Dof transcription factors up-regulate the andrographolide biosynthesis in Andrographis paniculata

Andrographis paniculata ( A. paniculata ) is a traditional Chinese medicinal plant that accumulates andrographolide, a key bioactive diterpenoid compound. In this study, we found that light can upregulate the production of andrographolide. However, the underlying regulatory mechanisms governing its biosynthesis remain elusive. By coupling the RNA-seq data obtained under different light conditions with co-expression analysis, two candidate transcription factors, ApDof16 and ApDof29 , were identified. Using virus-induced gene silencing (VIGS), we demonstrated that these two Dofs were able to regulate the content of andrographolide as well as the expression of ApCPS2 , a key gene of the andrographolide biosynthesis pathway. Further experiments, such as the yeast one-hybrid (Y1H) assays, transient assays and chromatin immunoprecipitation quantitative PCR (ChIP-qPCR) analysis indicated that ApDof29 rather than ApDof16 , directly binds to the promoter of ApCPS2 , thereby regulating its expression and the subsequent andrographolide accumulation in response to light. • Light enhances andrographolide biosynthesis in Andrographis paniculata. • ApDof16 and ApDof29 regulate light-induced andrographolide biosynthesis. • ApDof29 directly activates the key gene ApCPS2 , enhancing andrographolide synthesis.