Overexpression of PP2C Phosphatase causes differentation into stomata

Stomata are specialized epidermal cells that form channels to regulate gas exchange between underlying plant cells and its environment. The density of stomata is a critical parameter enabling plants to achieve optimal photosynthesis in relation to changing environmental factors, like drought or heat. This is emphasized by the observation of gradual increase of stomata density during global warming over the last 100 years. The stomata developmental pathway including cell lineage, cell-cell interactions and signals from a distance provide mechanisms to define the density and distribution of stomata within the epidermis. Recent works identified a receptor like protein, a receptor like kinase and a mitogen activated protein kinase kinase kinase controlling stomata differentiation. I have discovered a novel Arabidopsis gene that plays a role in stomata differentiation and belongs to the protein phosphatases of PP2C-type that I named STOPP (stomata phenotype phosphatase), based on its role to promote stomata development within the epidermis. Plants retain a large family of PP2C in comparison to other eukaryotes with only few characterized so far. In this project I aim to identify the signalling pathway that STOPP might regulate by uncovering the molecular mechanism how STOPP controls stomata density and identify in planta target proteins and their phosphorylation status.