Collaborative Research: Bilateral BBSRC-NSF/BIO: Regulation of plant stomatal aperture by SAUR (Small Auxin Up RNA) proteins

Abstract

Collaborative Research: Bilateral BBSRC-NSF/BIO: Regulation of plant stomatal aperture by SAUR (Small Auxin Up RNA) proteins.

Senior personnel: Jason Reed (PI, U. North Carolina), Punita Nagpal (co-PI, U. North Carolina), William Gray (PI, U. Minnesota), Michael Blatt (co-PI, U. Glasgow)

The ultimate goal of the project is to understand how leaf physiology can be controlled to improve plant yield during drought. Stomata are pores on plant leaves whose regulation balances the demand for carbon dioxide uptake for photosynthesis against excessive water loss through transpiration. A deeper understanding of the molecular and cellular mechanisms regulating stomatal aperture could result in enhanced function, potentially leading to improved crop yields under drought and other environmental stresses. Research under this collaborative project will provide training for postdoctoral researchers and undergraduate students in diverse experimental and computational techniques and approaches at the University of North Carolina and University of Minnesota in the U.S. and the University of Glasgow in the U.K. Together with high school teachers, the researchers will also design and implement lesson plans for high school students on stomatal aperture and its relationship to plant water use and drought tolerance.

Stomatal movements are critical for optimizing plant growth, and for adapting to changing environmental conditions including water availability, temperature, light, and CO2 levels. Stomatal opening and closing occur through changes in the turgor and shape of guard cells that flank each stomatal pore, which requires regulated movement of solutes and water across the plasma membrane and the tonoplast (vacuolar membrane). Mechanisms by which transporter activities are coordinated over the diurnal cycle and in variable environments are incompletely understood. The project will exploit two recent advances to elucidate stomatal aperture control. First, SAUR (Small Auxin Up RNA) proteins can promote stomatal opening, in part by regulating PP2C.D phosphatases that target membrane transporters. Second, computational models developed by the researchers enable simulations of guard cell physiology that can predict and explain effects of altered SAUR or PP2C.D regulation. A multidisciplinary approach including genetics, biochemistry, electrophysiology, and computational modeling will be used to determine mechanisms by which SAUR and PP2C.D proteins regulate stomatal aperture, whether different members of these families have different activities, and at what times and under what physiological conditions they act. The combined experimental and modeling approach will lead to understanding of novel mechanisms that regulate stomatal movements and integrate them into existing models of guard cell regulation. Such insights may suggest synthetic biology approaches to modify stomatal aperture or the kinetics of stomatal responses in crop plants, and enhance predictive models for the effects of environmental change on plant productivity.

This collaborative US/UK project is supported by the US National Science Foundation and the UK Biotechnology and Biological Sciences Research Council.