Collaborative Research: Cellular and Biomechanical Mechanisms of Rapid Stomatal Dynamics in Grasses

Stomata, which are microscopic pores on the surfaces of plants, are gateways that control photosynthesis in the crops that provide humanity with food and sustainable materials. This project investigates how stomata in grasses, which include staple food crops such as maize and wheat, are constructed with the capability to rapidly open and close to regulate photosynthesis and water transport in response to changing environmental conditions. The project will provide interdisciplinary graduate training and support discovery-based undergraduate research courses in molecular genetics, plant cell biology, computer vision, and biomechanics experimentation and modeling, expanding participation in these fields for diverse early-career scientists. The exciting biology of stomatal dynamics in plants and how understanding and engineering stomata can help address pressing societal challenges such as food security and climate change will be shared with K-12 students through a middle school summer camp and mentoring of high school students who will design and complete independent research projects. The outcomes of this work promise to help improve the efficiency with which plants capture carbon dioxide and convert it into food and useful materials such as fibers and wood.The four-celled stomatal complexes of grasses have been hypothesized to function via a “see-saw” mechanism by which the expansion of dumbbell-shaped guard cells is matched by deflation of the round subsidiary cells that flank the guard cells, enabling rapid adjustment of the size of the stomatal pore in response to environmental shifts. However, this hypothesis has not been rigorously tested, and our understanding of stomatal biomechanics and function in grasses is limited. This project combines molecular genetics, cell biology, computer vision, mechanical testing, and computer modeling of stomatal biomechanics to dissect the molecular, physiological, and cellular underpinnings of rapid stomatal dynamics in a model grass species, Brachypodium distachyon. The composition of the cell walls in guard and subsidiary cells will be manipulated in Brachypodium distachyon through advanced genetic engineering. The resulting changes will be examined with respect to stomatal function, biomechanical properties of the modified plants will be measured and modeled, and computer vision pipelines will be used to quantify changes in cell volumes and shapes. With these approaches, experimentally testable computational models of normal and altered stomatal complexes will help predict how stomatal function might be further optimized to enhance crop yields, water use efficiency, and carbon drawdown.This project is jointly funded by the NSF/BIO/MCB Cell Dynamics & Function Program and the Established Program to Stimulate Competitive Research (EPSCoR).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.