Analysis of heterotrimeric G protein signaling in maize development

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Heterotrimeric G protein signaling controls a wide range of developmental and physiological processes, including cell proliferation and growth. Work of the last decade has shown that G protein signaling in plants does not follow the classical paradigm established in animal systems. My recent identification and characterization of the maize COMPACT PLANT2 (CT2) gene, which encodes the G-alpha subunit of the heterotrimeric protein, provides a unique entry point to now analyze the underlying molecular mechanisms of heterotrimeric G protein signaling, which are still poorly understood. The complexity of the ct2 mutant phenotype supports the emerging view, that heterotrimeric G protein signaling is involved in many different processes and likely serves as a hub to integrate different regulatory pathways. Further results of mine suggest that in plants as in animals, heterotrimeric G Proteins serve multiple non-canonical roles in the cell. Starting from substantial preparatory work, I will dissect here how heterotrimeric G protein signaling in plants integrates extracellular signal perception with intracellular signal transduction and cytoskeleton dynamics to control cell proliferation and growth. I will start by analyzing the network structure of the G protein signaling and ask in particular whether and if so how BR signaling intersects with the heterotrimeric G-alpha subunit to control plant height, which is a major yield related trait in crops. In a second part, I will explore non-canonical heterotrimeric G protein function in maize, especially during the regulation of the plant cytoskeleton. To complement both parts, I will use the power of maize genetics to identify EMS induced and naturally occurring enhancer and suppressors of G-alpha mediated signaling. Finally, I will follow a functional genomics approach and systematically identify and characterize mutants in all six maize G-gamma subunits. The combination of these complementary approaches will allow me to systematically assess heterotrimeric G protein signaling in plants with respect to the organization of plant architecture. The expected data will not only provide fundamental insights into this not much explored signaling pathway but also deliver knowledge about crop improvement. With this, the project also represents a solid base for a long-term career in science and my reintegration into the German university system.