Fig. 1: The biosynthetic pathway of non-bitter and less toxic Esculeoside A during tomato fruit development and ripening.

The known SGA biosynthetic enzymes (i.e., GAME31, GAME40, and GAME5) in the Esculeoside A pathway are marked in black. The GAME36 enzymatic step discovered in this study is shown in green. Specific activity displayed by these GAME enzymes is shown in red on the SGAs structures. A detailed pathway of tomato SGAs biosynthesis, including the dehydro-SGA branch is presented in Supplementary Fig. 1. GAME: GLYCOALKALOID METABOLISM; Glu: Glucose; Gal: Galactose; Xyl: Xylose; Rha: Rhamnose; Ac: Acetoxy.