HIGHCODE · Unravelling high CO2-induced changes in stomatal development

Stomata are epidermal valves responsible for gas exchange in plant aerial tissues. Their number varies according to different environmental conditions, such as CO2 concentration. High CO2 levels negatively regulate stomatal development, but how such a repression works is poorly understood. In Arabidopsis thaliana, stomatal precursor cells develop asynchronously throughout leaf epidermis, undergoing a first asymmetric entry division that generates a small meristemoid and a larger stomatal lineage ground cell (SLGC). Meristemoids can go through up to three asymmetric amplifying divisions before forming mature stomata, while SLGCs can either undergo asymmetric spacing division or differentiate into pavement cells. How each of the three meristemoid division types are affected by CO2 is still unknown. Moreover, stomata form with the underlying mesophyll layer in a coordinated way. Both tissues are involved in CO2 sensing and high CO2 levels can affect their development. What are the factors regulating stomatal development modulation, and whether or not an interlayer coordination is required upon high CO2 conditions, has remained unexplored. The proposed project aims to unravel CO2-induced developmental response in leaf, understanding 1) how stomatal asymmetric divisions are affected by CO2, 2) what are the layer-specific regulators, 3) the mechanisms of developmental response. Spatiotemporal lineage tracing, tissue-specific transcriptomics and creation of selected mutant lines will be employed to elucidate how CO2 modulates leaf developmental program. To reach the proposed goals, I will be supervised in advanced confocal microscopy, bioinformatic analysis, oral and written communication of the research and developing of transferable skills. My previous experience as developmental biologist and with transcriptomic analysis, together with teaching and tutoring skills acquired, will help accomplishing the project goals.