In plants, stomatal guard cells influence both photosynthesis and water transport and are thus essential for growth and efficient water use. However, our understanding of guard cell function at the cellular and molecular levels is limited. This project studies how guard cells dynamically expand and shrink to open and close stomatal pores, controlling the uptake of carbon dioxide and the release of oxygen and water by the plant. Understanding how guard cells function will aid in the development of resilient, high-yielding crops that can grow in hot, dry environments and more effectively remove carbon dioxide from the atmosphere. The image analysis and modeling tools created in this project will allow researchers to predict the behavior of a wide range of mechanical behaviors and responses by cells. This multidisciplinary project will train three PhD students as future leaders across the topics of cell biology, computational image analysis, and mechanical testing and modeling of biological systems, and will spread knowledge of guard cells and plant biology using learning modules and research experiences for K-12 and undergraduate students.
Despite decades of research interest, the molecular and biophysical mechanisms by which stomatal guard cells function remain incompletely understood. In particular, the roles of the cell wall and water flux in guard cells and neighboring cells in stomatal mechanics are not fully defined. This project combines molecular genetics, cell biology, advanced microscopy, computational image analysis, nanoindentation, and computational modeling to measure and model turgor pressure and wall mechanics in wild type and mutant stomatal complexes of the model plant Arabidopsis thaliana. These analyses will be used to examine the biomechanics of guard cells and the dynamic mechanical and functional relationships between guard cells and their neighboring cells. Another major goal of the project is to use super-resolution microscopy to develop a clear picture of the molecular composition and architecture of the guard cell wall, and to use these data to construct detailed, accurate, and experimentally testable finite element and multiscale, multiphysics models of stomatal guard cells. Together, this work will enable the prediction of stomatal dynamics across a range of species, wall compositions, stomatal geometries, and signaling inputs.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
