Synthetic Genetic Circuits to Modify Plant Root Structure

Plant structure affects environmental stress tolerance. For example, the shape of a plant’s root system influences its ability to reach essential nutrients in the soil or to acquire water during drought. Progress in engineering plant structure has been limited by our capacity to design and build genetic programs that alter growth in a predictable manner. We have built a library of synthetic transcription factors and used them to create synthetic genetic circuits that generate new spatial patterns of gene expression in Arabidopsis roots. Nicotiana benthamiana was used as a testbed to accelerate the design-build-test cycle of these circuits and enable productive tuning of circuit behavior. We apply the circuits to modify root structure by specifically changing root branching and gravitropism. This work highlights the utility of genetic circuits to enable precise spatial, temporal, and magnitudinal control over gene expression across entire organ systems and offers an exciting means to reprogram plant growth.