SGER: Signalling and the Stomatal Response to Humidity

Utah State University, Logan UT

Investigators

Abstract

Although most stomatal responses to environmental factors appear to be sensed and transduced within the guard cells, circumstantial evidence suggests that this is not the case for the stomatal response to humidity. This project investigates the possibility that small changes in turgor pressure in the mesophyll or epidermal cells initiates a cellular signaling pathway that ultimately leads to changes in guard cell osmotic pressure associated with stomatal responses to humidity. The influence of humidity changes on intercellular concentrations of Ca2+ and components of phosphoinositide signaling pathways will be assessed in both epidermal and mesophyll cells. HPLC will be used to quantify components of the phosphoinositide signaling pathway, and fluorescent probes will be used to quantify intercellular Ca2+ concentrations. For the latter experiments, a ratiometric fluorescent calcium indicator protein (cameleon) has been expressed in Arabidopsis thaliana. The project will provide new insights into the mechanism for the stomatal response to humidity. This response has a major effect on the overall water use efficiency of plants in both natural and agricultural settings.