Cellular Mechanisms of Abiotic Stress Tolerance in Plants

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Being sessile organisms, plants are continuously exposed to various biotic and abiotic stresses that limit their growth or even cause death. In agricultural terms, environmental stresses such as extreme temperatures, high salinity drought, and pathogen attacks constitute the principal cause of yield loss by diminishing crop performance worldwide to ca. 20% of their genetic potential. This problem is further exacerbated by the global climate change and weather fluctuations bound to widely increase production instability and to degrade natural resources. To cope with these major constraints to agricultural production, the development of crops that are tolerant to environmental stresses, and therefore ensure productivity under harsh conditions, has become of paramount importance for plant researchers. To achieve this important long-term goal, the study of wild species adapted to different environmental stresses, such as the model plant Arabidopsis thaliana, is essential to provide genetic resources and broaden the narrow genetic base of cultivated crops. Moreover, the enhancement through breeding of stress tolerance traits will also require a detailed understanding of the roles of various genes and proteins in cell membrane damage control during stress episodes, one of the first cellular responses required for the plant stress tolerance. ** The research program proposed here will use the resources from the model plant Arabidopsis thaliana to identify and characterize the cellular mechanisms underlying abiotic stress tolerance in plants. Specifically, we will study a recently discovered family of plant proteins, the synaptotagmin family, which mediates the membrane fusions required to maintain the structural integrity of plant cells during stress episodes. We will also identify Arabidopsis mutants unable to maintain the cellular membrane integrity under harsh conditions, and we will isolate the corresponding genes needed for the tolerance to abiotic stresses. Using these approaches we propose to study: 1) The specific effects of single and combined environmental stresses in plant cell membranes, 2) The biochemical properties of the membranes required to maintain cellular stability under stress conditions, 3) The subcellular mechanisms by which synaptotagmins control membrane fusions, 4) The identity of additional protein components involved in membrane stability and repair during stress episodes. Knowledge about the subcellular mechanisms and proteins involved in cellular membranes stability and repair will enable the future development of stress-tolerant crops, ensuring high yield under adverse environmental conditions for a long-term sustainable agriculture.