Molecular basis of abiotic stress tolerance of plants

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Grapevine has worldwide economic significance because it is used for viticulture in countries around the world, including Canada. Freezing temperatures can be detrimental for a plant's survival in Canada with winter temperatures below -20C. Cultivars, including those used in the Canadian fruit and wine Industry, are affected and even killed in severe winters, resulting in a substantial economic impact to the Industry. Indeed, lack of sufficient winterhardiness is the greatest threat to the production of the elite winegrape Vitis vinifera in Canada. Interestingly, many native species survive after being subjected to a period of low, non-freezing temperatures. Understanding how native species achieve freezing tolerance is thus important. Key genes that are activated during cold acclimation in the native V. ripara grape and thought to regulate the molecular cascade leading to freezing tolerance have been identified, but found to also affect plant development. The long term goal of my lab is to determine which combination of these genes could provide freezing tolerance to the cultivated grape without any undesirable developmental effects. The proposed project will investigate for each potential key gene under which conditions it produces an active protein product, which other genes this protein then regulates and what effect this activated cascade has on the plant. Additional experiments will determine if the difference in freezing tolerance between the cultivated grape and the wild grape can be explained by one or more of the noted differences between their key proteins. Taken together this project will deliver fundamental knowledge on the genetic basis of stress tolerance in grape. Grape is a deciduous woody perennial and thus will provide crucial information specific to perennial plants that cannot be obtained by studying the model plant Arabidopsis. The project will provide the information necessary to guide a balanced approach to the production of winegrape cultivars with increased abiotic stress tolerance either by conventional breeding or assisted (transgenic) breeding. This application could be extended also to other woody perennial crops such as peaches or plums.