Glyceollin biosynthesis in a plant chassis engineered for isoflavone production

Glyceollins are structurally complex potent antimicrobial isoflavonoid phytoalexins produced by the crop soybean (Glycine max), yet their biosynthesis remains elusive, making it impossible to carry out synthetic biology-based production and engineering for further development. Here, via assembling synergistic engineering strategies, we successfully rewired the metabolic fluxes in Nicotiana benthamiana leaves for high-yield production of isoflavonoid precursor daidzein (7.04 g kg^-1 dry weight (dw)), allowing for efficient screening and identification of six cytochrome P450 monooxygenases, namely glyceollin synthases, that furnish the pyrano/furano E ring and complete the 15-step biosynthetic pathways of diverse glyceollins. We establish that purified glyceollins are important for plant defense as they can effectively suppress the growth of Phytophthora sojae in vitro. Our engineered plant chassis can provide facile access to bioactive isoflavonoids, as manifested by the de novo total biosynthesis of glyceollins (for example, I, II, III and VII at up to 5.9 g kg^-1, dw) and medicarpin (0.72 g kg^-1, dw) for enhanced pathogen resistance and medicinal value.