We developed methods to extract quantitative parameters of repressible promoters using protoplast assays as part of a project to build synthetic switches to control functions in plants. Experiments were conducted to identify the sources of variability and a statistical model was created to account for this variability. The parameters obtained from the statistical model were used to predict how effective the repressors would be when combined together to form a genetic toggle switch. Over one hundred genetic components in two plant species, Arabidopsis and Sorghum, were studied, and candidates for switches were identified. More complex circuit designs were predicted in silico and preliminary results of these more complex circuits transformed into plants are presented here.
