"Plant life strategy is marked by acquisition of highly flexible development that adapts plants’ phenotype to the environment. Various environmental signals are integrated into the endogenous signalling networks involving the versatile phytohormone auxin. The intercellular auxin transport mediates a large variety of adaptive plant growth responses. Subcellular polar distribution of PIN auxin transporters determines directionality of auxin flow and thus have potential to integrate internal and external signals via the redirection of auxin fluxes and translate them into modulation of development. Auxin transport thus represents a unique model for studying the functional link between basic cellular processes, such as vesicle trafficking and cell polarity, and their developmental outcome at the level of the multicellular organism.We will employ approaches of cell biology, molecular genetics and chemical genomics in Arabidopsis thaliana to identify the cellular and molecular mechanisms regulating the directional throughput of auxin flow a integration of environmental signals into subcellular dynamics of PIN auxin transporters as well as endogenous feed-back regulations of this mechanism.In our proposal, we will focus on four main research directions.1. Novel regulators of cell polarity identified by chemical genomics2. Cellular mechanisms of cell polarity maintenance3. Integration of signals into subcellular dynamics of auxin transport4. Mathematical modelling of regulatory circuits for adaptive developmentThe results will demonstrate the viability of genetics approaches for addressing cell biological questions in plants, open new horizons in plant cell biology and plant hormone fields and inspire researchers also in non-plant fields. The expected output has clear application potential for targeted modulation of plant development. The project will further strengthen our position of world-leading laboratory in plant hormone and plant cell biology fields."