Engineering Sclareol Production on the Leaf Surface of .

Sclareol, a diterpene alcohol, is the most common starting material for the synthesis of ambrox, which serves as a sustainable substitute for ambergris, a valuable fragrance secreted by sperm whales. Sclareol has also been proposed to possess antibacterial, antifungal, and anticancer activities. However, in nature, sclareol is only produced by a few plant species, including , , , and , which limits its commercial application. In this study, we cloned the two genes responsible for sclareol biosynthesis in , labda-13-en-8-ol diphosphate synthase () and sclareol synthase (), and overexpressed them in tobacco ( L.). The best transgenic tobacco lines accumulated 4.1 μg/cm of sclareol, which is comparable to the sclareol production of , a natural sclareol producer. Thus, sclareol synthesis in tobacco represents a potential alternative means for the production of this high-value compound.