Figure 2. Engineering plant primary metabolism for the production of target bioproducts or secondary metabolites.

A simplified view of global primary metabolism is highlighted in yellow, with various branches that may be engineered to produce specific molecules of interest highlighted in the outer brown area. Co-products may be harvested alongside plant cell wall biomass, which is broken down as a monosaccharide feedstock for downstream microbial fermentative processes. Platform chemicals encompass many diverse molecules that span across all of primary metabolism; however, here we have only highlighted the example of muconic acid that may be engineered from various intermediates of the shikimate pathway. Many secondary metabolites derived from phenylpropanoids or amino acids are involved in plant disease resistance as biopesticides and may confer relevant agricultural traits.