Collaborative Research: Redox and Metabolomic Regulatory Mechanisms Underlying Guard Cell ABA Signal Transduction

Intellectual Merit. The research team will use modern biological tools to understand signal transduction processes of an important plant hormone, abscisic acid (ABA), in guard cells. Guard cells are highly specialized plant epidermal cells that enclose tiny pores called stomata. Stomatal movements (enabled by turgor changes in guard cells) control both CO2 uptake for photosynthesis and transpirational water loss, and thus play important roles in plant growth and acclimation to environmental stresses. ABA is a key indicator of drought stress. It induces stomatal closure via an intricate intracellular signaling network comprised of proteins and metabolites, thereby promoting plant water conservation. This research will analyze the roles of many proteins, especially those subject to reduction and oxidation (redox) modifications, in guard cell ABA signal transduction. Dynamic changes in key intracellular metabolites in guard cells upon ABA treatment will also be characterized. The project is expected to identify novel redox-regulated proteins and metabolites and put them into functional context of ABA signal transduction. The resources from this project will be distributed via a publicly accessible web interface and FTP sites for maximum scientific impact. The project is expected to provide comprehensive knowledge of regulatory mechanisms underlying stomatal movements that will help to develop crops with enhanced drought tolerance and improved productivity.

Broader Impacts. This project will benefit society at large because a better understanding of ABA signal transduction will inform rational crop engineering for better agricultural yield and stress tolerance. Since protein redox regulation is a ubiquitous biological process, occurring in essentially every organism including plants, animals, and micro-organisms, the data, techniques and resources developed in the project will be of immediate value to a broad range of scientists and will be disseminated via a web interface and FTP sites, as well as in publications and at scientific conferences. The project will involve cross-disciplinary training of personnel, including high school students, undergraduate and graduate students, in the frontiers of modern biological sciences. Given that knowledge of large-scale and high-throughput protein analysis (proteomics) is still not widespread, a proteomics workshop will be offered to graduate students and post-doctorates nationwide. Graduate students and post-doctorates from the Chen and Assmann laboratories will participate in developing and running the workshop, thus gaining valuable experience in teaching outside the standard classroom setting. Students from under-represented groups will be recruited for the training opportunities. Overall, the training and outreach program is designed to help prepare the next generation of scientists for competitive careers in modern biology.