Regensburg 2019 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 6: Poster I

BP 6.21: Poster

Montag, 1. April 2019, 17:30–19:30, Poster B2

Dynamic patterns of the plant growth regulator auxin — •Joao Ramos and Karen Alim — Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany

Auxin is a plant hormone that promotes growth by altering the mechanical properties of the cell wall, ubiquitously acting throughout plant development. Specific morphologies are tied to patterns of auxin concentration and flow emerging from carrier mediated cell-cell auxin transport. In particular, efflux carrier proteins of the PIN family are the main players in directing auxin flow. Recent data suggest that PIN polarity and mechanical stress may be causally linked. In order to explore the interplay between auxin-mediated cell wall loosening, growth and mechanically-regulated PIN polarity, we have developed a mechanical vertex model coupled to a compartment model for auxin transport. We apply our model to the developmental process of lateral root formation (LRF), which offers empirical accessibility as well as a wide range of developmental patterns accompanied by a wide variety of impactful mechanical cues. Here, we can explain auxin flows down-the-gradient of auxin concentration, present in fountain-like patterns during LRF, by the competition between stress or stiffness gradients and PIN expression. During early LRF, we can explain auxin accumulation and founder cell swelling through differential turgor pressure. Independent of a specific developmental process, we show that mechanical relaxation of cell geometry amplifies mechanically-mediated PIN polarity.