Identification of the Trichome Patterning Core Network Using Data from Weak ttg1 Alleles to Constrain the Model Space
Rachappa Balkunde, Anna Deneer, H. Bernard Bechtel, Bipei Zhang, Stefanie Herberth, Martina Pesch, Benjamin Jaegle, Christian Fleck, Martin Hülskamp
Abstract
The regular distribution of trichomes on leaves in Arabidopsis is a well-understood model system for two-dimensional pattern formation. It involves more than 10 genes and is governed by two patterning principles, the activator-inhibitor (AI) and the activator-depletion (AD) mechanisms, though their relative contributions are unknown. The complexity of gene interactions, protein interactions, and intra- and intercellular mobility of proteins makes it very challenging to understand which aspects are relevant for pattern formation. In this study, we use global mathematical methods combined with a constraining of data to identify the structure of the underlying network. To constrain the model, we perform a genetic, cell biological, and biochemical study of weak ttg1 alleles. We find that the core of trichome patterning is a combination of AI and AD mechanisms differentiating between two pathways activating the long-range inhibitor CPC and the short-range inhibitor TRY.