Unraveling phosphate signaling by developing whole plant Live Transcriptional IMaging – ULTIM

Project abstract
Transcriptional control is essential for plants to adapt to ambient fluctuations. By implementing the latest MS2 RNA imaging system combined with microfluidics, we achieved real-time quantitative measurements of the transcriptional activity of single loci, in all cells of entire organs of living Arabidopsis. Here, we will bring these technologies to a new level, optimized for whole organism imaging. We will develop: (i) brighter and multicolor live cell RNA imaging technologies, using several strategies and in particular nanobody signal amplification; (ii) new software based on machine-learning to automatically and accurately analyze image data. These tools will be combined with genetics to unravel the complex transcriptional control triggered by an essential plant macronutrient: phosphate. We will address the fundamental question of how single cell responses, known to be noisy and heterogenous, are integrated into a coordinated response at the organism level. The progress brought by this project will provide tools and concepts that will renew our vision of transcriptional regulation from plants to metazoans.