Abstract

The essential oil of German chamomile (Matricaria recutitaL.) is widely used in food, cosmetics, and the pharmaceutical industry. α-Bisabolol is the main active substance in German chamomile. Farnesyl diphosphate synthase (FPS) and α-bisabolol synthase (BBS) are key enzymes related to the α-bisabolol biosynthesis pathway. However, little is known about the α-bisabolol biosynthesis pathway in German chamomile, especially the transcription factors (TFs) related to the regulation of α-bisabolol synthesis. In this study, we identifiedMrFPSandMrBBSand investigated their functions by prokaryotic expression and expression in hairy root cells of German chamomile. The results suggest that MrFPS is the key enzyme in the production of sesquiterpenoids, and MrBBS catalyzes the reaction that produces α-bisabolol. Subcellular localization analysis showed that both MrFPS and MrBBS proteins were located in the cytosol. The expression levels of bothMrFPSandMrBBSwere highest in the extension period of ray florets. Furthermore, we cloned and analyzed the promoters ofMrFPSandMrBBS. A large number ofcis-acting elements related to light responsiveness, hormone response elements, andcis-regulatory elements that serve as putative binding sites for specific TFs in response to various biotic and abiotic stresses were identified. We identified and studied TFs related toMrFPSandMrBBS, includingWRKY,AP2, andMYB. Our findings reveal the biosynthesis and regulation of α-bisabolol in German chamomile and provide novel insights for the production of α-bisabolol using synthetic biology methods.Keywords:German chamomile;α-bisabolol;MrFPS;MrBBS;transcription factor