Identification of the Trichome Patterning Core Network Using Data from Weak ttg1 Alleles to Constrain the Model Space

• Published in: Cell reports (Cambridge) Vol. 33; no. 11; p. 108497
• Main Authors: Balkunde, Rachappa, Deneer, Anna, Bechtel, Hanna, Zhang, Bipei, Herberth, Stefanie, Pesch, Martina, Jaegle, Benjamin, Fleck, Christian, Hülskamp, Martin
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.12.2020; Elsevier
• Subjects: Alleles; Arabidopsis; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Gene Expression Regulation, Plant - physiology; gene regulatory network; mathematical modelling; patterning; trichomes; Trichomes - genetics; Arabidopsis thaliana; trichomes; mathematical modelling; patterning; gene regulatory network
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2020.108497

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. [Display omitted] •Complex changes in trichome patterning are explained by reduced TTG1 GL3 interaction•Mathematical modeling and data constrainment reveal the network structure•Trichome patterning requires an activator-inhibitor and an activator-diffusion mechanism•Trichome patterning requires two pathways activating long- and short-range inhibitors Mathematical modeling of developmental processes is challenging because most of the parameters are normally unknown. Balkunde et al. use weak trichome patterning mutants to constrain the data and use global mathematical methods to identify the core parts of the complex gene regulatory network that are essential for patterning.