Brassinosteroids (BR) are key hormonal regulators of plant development. However, whereas the individual components of BR perception and signaling are well characterized experimentally, the question of how they can act and whether they are sufficient to carry out the critical function of cellular elongation remains open. Here, we combined computational modeling with quantitative cell physiology to understand the dynamics of the plasma membrane (PM)-localized BR response pathway during the initiation of cellular responses in the epidermis of the Arabidopsis root tip that are be linked to cell elongation. The model, consisting of ordinary differential equations, comprises the BR induced hyperpolarization of the PM, the acidification of the apoplast and subsequent cell wall swelling. We demonstrate that the competence of the root epidermal cells for the BR response predominantly depends on the amount and activity of H+-ATPases in the PM. The model further predicts that an influx of cations is required to compensate for the shift of positive charges caused by the apoplastic acidification. A potassium channel was subsequently identified and experimentally characterized, fulfilling this function. Thus, we established the landscape of components and parameters for physiological processes potentially linked to cell elongation, a central process in plant development.
All data generated and analysed during this study are included in the manuscript and the supporting file (Appendix 1). Raw and metadata are provided for Figures 4, 5, 6, 7 and 8 as well as for Appendix 1 Figures 2, 3, 4 and 6. Figure 1 represents scheme of early BRI1 signaling and Figure 2 the scheme of the used model structure. Predominantly published scRNA-Seq data were used for Figure 3. Modelling codes are available in supporting file (Appendix 1 - model information).
Spatiotemporal development trajectories in the Arabidopsis root revealed using high-throughput single-cell RNA sequencingNCBI Gene Expression Omnibus GSE123818.
- Karin Schumacher
- Ursula Kummer
- Klaus Harter
- Klaus Harter
- Ruth Großeholz
- Ruth Großeholz
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Krzysztof Wabnik, CBGP Centro de Biotecnologia y Genomica de Plantas UPM-INIA, Spain
© 2022, Großeholz et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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