MicroRNAs (miRNAs) have attracted increasing attention in the field of medicinal plant research. Our previous analyses indicated that the mature miR160a level was related to the accumulation of tanshinones in Salvia miltiorrhiza (S. miltiorrhiza). Therefore, the aim of this research was to reveal how the miR160a regulates the tanshinones biosynthesis. The overexpression of miR160a in hairy roots of S. miltiorrhiza down-regulated the levels of the target genes ARF10, 16, and 17, and inhibited tanshinones biosynthesis but increased hairy root biomass. In overexpression line 1, the content of four major tanshinones dropped sharply to 9.06% (dihydrotanshinone I), 12.56% (cryptotanshinone), 12.02% (tanshinone I), and 8.52% (tanshinone IIA) compared with that of the wildtype (WT). The fresh weight (FW) of hairy roots increased to 1.72-fold of the WT, and in overexpression lines 4, tanshinones were not detected. However, the FW of hairy roots in overexpression line 4 increased to 1.90-fold of the WT. We also observed the down regulated genes in the tanshinones biosynthesis pathway. In particular, the transcription level of KSL2 dropped to 3% as compared to the WT, which was consistent with the decrease in tanshinones content. We further analyzed hormone changes and found an increase in indole acetic acid accumulation, while the accumulation of salicylic acid (SA) and jasmonic acid (JA) decreased. These findings indicate that miR160a may negatively regulate the biosynthesis of tanshinones, while promote the growth of hairy roots by targeting ARF10, 16, and 17. Our findings demonstrate that miRNAs could be used as an alternative strategy to dissect the complex network of secondary metabolism in medicinal plants.

在药用植物研究领域中，MicroRNA（miRNA）引起了越来越多的关注。我们以前的分析表明，成熟的miR160a水平与丹参中丹参酮的积累有关（S. miltiorrhiza）。因此，本研究的目的是揭示miR160a如何调控丹参酮的生物合成。miR160a在丹参毛状根中的过表达下调了靶基因ARF10、16和17的水平，并抑制丹参酮的生物合成，但增加了毛状根的生物量。与野生型（WT）相比，过表达谱系1中四种主要丹参酮的含量急剧下降至9.06％（二氢丹参酮I），12.56％（隐丹参酮），12.02％（丹参酮I）和8.52％（丹参酮IIA）。 。毛状根的鲜重（FW）增加到WT的1.72倍，在过表达系4中，未检测到丹参酮。然而，过表达系4中毛状根的FW增加至WT的1.90倍。我们还观察到了丹参酮生物合成途径中的下调基因。特别是KSL2的转录水平与野生型相比下降了3％，这与丹参酮含量的下降是一致的。我们进一步分析了激素变化，发现吲哚乙酸积累增加，而水杨酸（SA）和茉莉酸（JA）的积累减少。这些发现表明，miR160a可能负面调控丹参酮的生物合成，同时通过靶向ARF10、16和17促进毛状根的生长。我们的研究结果表明，miRNA可以用作解剖药用植物次级代谢复杂网络的替代策略。