Metabolic Engineering of Floral Scent: Toward the Control of Flower Smell

Floral scent plays an important role in the reproductive processes of many plants, and has important economic value in guaranteeing yield and quality of many crops as well as enhancing the aesthetic properties of ornamental plants and cut flowers. The chemistry of plant volatiles is well understood, however, little is known about the biosynthesis of this diverse group of compounds. How do plants produce volatile compounds? What molecular mechanisms control their accumulation and release? We have integrated metabolic profiling, a functional genomic approach, and targeted metabolic engineering with metabolic flux analysis and modeling, to provide a comprehensive understanding of the regulation of flux through metabolic networks. We used different approaches for metabolic engineering of the spectrum of volatile metabolites, including the modification of existing pathways by shifting metabolic flux towards target compounds and the introduction of novel scent compounds normally not found in the host plant. We will discuss critical factors that limit volatile trait modification and present approaches for rational metabolic engineering of volatile emission based on computer-assisted metabolic flux analysis.