miR160a-ARF4 module regulates the biosynthesis of Panax notoginseng saponins.

Panax notoginseng is an economically vital medicinal plant, prized for its bioactive P. notoginseng saponins (PNS), which possess significant therapeutic effects in cardiovascular and cerebrovascular diseases. Despite the elucidation of the core enzymatic steps in PNS biosynthesis, the posttranscriptional mechanisms that coordinate these metabolic fluxes remain largely obscure. This study explored the Pn-miR160a-ARF4 module as a pivotal regulation mode in the biosynthesis of PNS. Under methyl jasmonate stimulation, Pn-miR160a was significantly upregulated, subsequently targeting and cleaving the transcripts of auxin response factor 4 (PnARF4). This targeted silencing of PnARF4 effectively relieves its transcriptional repression, thereby promoting the expression of downstream biosynthetic genes and increasing PNS yield. By integrating hormonal signaling with miRNA-mediated gene silencing, these results uncover a sophisticated regulatory axis that governs specialized metabolism. Furthermore, this work expands the known functional scope of the evolutionarily conserved miR160-ARF module beyond its traditional role in plant architecture and auxin signaling, repositioning it as a central component of secondary metabolic regulation. These findings provide a theoretical foundation and a robust molecular target for the metabolic engineering and genetic improvement of P. notoginseng quality.