Stomatal development and frost tolerance pathways in grape

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The long-term goal of my research program is to elucidate the regulation of stress tolerance and stomata formation in perennial plants. Extreme temperatures and drought are major stresses that affect the distribution of plants in nature and limit plant productivity in agriculture. Climate change brings with it an increase in such stress conditions. How plants adapt to various abiotic stresses is a fundamental biological question, and improving plant stress tolerance is critical for maintaining or improving agricultural productivity required for food security. Stress tolerance is especially important for perennial plants because damage incurred during one year negatively affects performance and yield also in subsequent years and thus will have considerable economic impact for several years. Some plant species and varieties are able to adjust better to changing adverse environmental conditions than others. For example, wild grape plants (Vitis riparia) can survive Canadian winters with freezing temperatures better than domesticated plants used for wine production, such as V. vinifera. The question is why? It has been suggested that the perception of low temperatures in the fall initiates a series of events, collectively referred to as cold acclimation, that lead to increased frost tolerance. Transcription factors which regulate key steps in this process have been identified for the model plant Arabidopsis thaliana. Their expression and activity was found to be tightly regulated to minimize negative effects on plant development. Interestingly, a protein called ICE (Inducer of CBF Expression; whereby CBF= CRT Binding Factor) not only has a function in the frost tolerance pathway but also in the formation of stomata, openings that regulate the loss of water from leaves and thereby affect drought tolerance. ICE acts in concert with the core stomatal proteins SPEECHLESS (SPCH), MUTE and FAMA. I propose to explore the differences between annual (Arabidopsis) and perennial plants and the effects of domestification (V. riparia versus V. vinifera) on the evolution of key proteins (ICE, CBF, SPCH, MUTE and FAMA) involved in stress responses and development. My lab has been studying grape plants for more than 16 years and is well positioned to take on this task. The proposed research will determine the roles of each grape protein and how their activity is regulated. The results will be used to identify what protein modifications would allow grape plants to survive freezing temperatures without compromising their growth and formation of stomata. This research will provide valuable information about the fundamental processes overwintering plants use to survive harsh environmental conditions, and generate ideas and tools for producing superior wine grapes, with potential application to other perennial crops.