Seminars

Plants adapt constantly to environmental fluctuations through spatial and temporal transcriptional responses. Combining latest generation of MS2 RNA labelling system with microfluidics provide capacity to monitor impact of transcriptional modification triggered by phosphate supply. A fusion between GFP and the coat protein of bacteriophage MS2 (MCP-GFP), recognizing a specific RNA stem-loop inserted in multiple copies into a reporter RNA is used. This enabled quantitative measurements of the transcriptional activity of single loci in living Arabidopsis plants, providing direct visualization of transcriptional regulation within entire organs. Using phosphate responsive genes as model, we found that active genes displayed high transcription initiation rates and frequently clustered together in endo-replicated cells. We also observed large differences between alleles of single cells and in agreement, intrinsic noise was larger than extrinsic variations. Moreover, we established that the transcriptional repression triggered in roots by phosphate, a crucial macronutrient limiting plant development, occurred with unexpected fast kinetics in the range of minutes, and with striking heterogeneity between neighboring cells. Access to single cells RNA polymerase II dynamics within live plants will benefit the study of numerous signaling processes. In addition, we will present the recent developments of this technique combined with Anchor locus marker and a novel generation of fluorescent markers for plants to study protein/protein interactions.  

References:
Hani et al., 2021. Live single-cell transcriptional dynamics via RNA labelling during the phosphate response in plants. Nature Plants. 7; 1050-64
Mechichi et al., 2021. ANCHOR: A Technical Approach to Monitor Single-Copy Locus Localization in Planta. Frontier in Plant Science 12.