Tunable control of insect pheromone biosynthesis in Nicotiana benthamiana

Synthetic regulatory elements that provide control over the timing and levels of gene expression are useful for maximizing yields from heterologous biosynthetic pathways. Previous work has demonstrated that plants and microbes can be engineered to produce insect sex pheromones, providing a route for low-cost production of these compounds, which are valued for species-specific control of agricultural pests. Strong constitutive expression of pathway genes can lead to toxicity and metabolic loads, preventing normal growth and development and thus limiting biomass and affecting overall yields. In this study we demonstrate the ability to inducibly control the accumulation of Lepidopteran sex pheromones in leaves of Nicotiana benthamiana. Further, we show how construct architecture influences expression and product yields in multigene constructs, applying this to control the relative expression of genes within the pathway, thereby tuning the accumulation of pheromone components. The approaches demonstrated here provide new insights into the heterologous reconstruction of metabolic pathways in plants.