Transcriptional Rewiring: Engineering Plant Stress Response

Plant defence responses are modulated by substantial transcriptional reprogramming, up to 40% of the genome can be differentially expressed following pathogen challenge. These differentially expressed genes include hundreds of transcription factors suggesting a complex transcriptional network regulates plant stress responses. I will present how we are using transcriptional rewiring, of plant defence regulators, to engineer plants with enhanced tolerance to pathogens. Transcriptional rewiring involves the fusion of transcription factor coding sequences with non-natural promoter sequences, which, in turn can have pleotropic cascade effects on downstream target pathways. We have previously shown that transcriptional rewiring can be used to generate novel phenotypic diversity that can adapt yeast to stresses associated with heterologous expression. Here I will show how we are using a combination of Synthetic and Systems Biology, inspired by our studies in yeast, to select plant regulators for targeted rewiring approaches to enhance plant tolerance to pathogens. First, we model the transcriptional network using transcriptome time series data. From this network we select genes with characteristic network topological properties. Promoters and coding sequences of the selected genes are then rewired and constructs screen for altered stress response. Rewired regulators exhibit a range of altered plant stress response phenotypes highlighting the ability of our modelling to identify key network components of stress response. Importantly, several rewired constructs appear to improve tolerance to stress suggesting such approaches could be used to design new crops with improved stress tolerance.