A computational approach for inferring the cell wall properties that govern guard cell dynamics.

Abstract

Guard cells dynamically adjust their shape in order to regulate photosynthetic gas exchange, respiration rates and defend against pathogen entry. Cell shape changes are determined by the interplay of cell wall material properties and turgor pressure. To investigate this relationship between turgor pressure, cell wall properties and cell shape, we focused on kidney-shaped stomata and developed a biomechanical model of a guard cell pair. Treating the cell wall as a composite of the pectin-rich cell wall matrix embedded with cellulose microfibrils, we show that strong, circumferentially oriented fibres are critical for opening. We find that the opening dynamics are dictated by the mechanical stress response of the cell wall matrix, and as the turgor rises, the pectinaceous matrix stiffens. We validate these predictions with stomatal opening experiments in selected Arabidopsis cell wall mutants. Thus, using a computational framework that combines a 3D biomechanical model with parameter optimization, we demonstrate how to exploit subtle shape changes to infer cell wall material properties. Our findings reveal that proper stomatal dynamics are built on two key properties of the cell wall, namely anisotropy in the form of hoop reinforcement and strain stiffening.

Plant phenotyping relevance

3D生体力学モデルとパラメータ最適化により、気孔の形状変化から細胞壁の物性を推定する方法を開発し、変異体実験で検証しており、表現型取得・推定が研究の中心である。

Code and data availability

The paper's authors explicitly state that all simulation, data-processing, and graphing scripts for their guard cell biomechanical model are freely available in a public GitHub repository (stomasimulator), which is a paper-specific, publicly actionable code asset. No separate public phenotype dataset deposit is stated;