Cellular Mechanisms of Abiotic Stress Tolerance in Plants

作为无根生物，植物不断受到各种生物和非生物胁迫，这些胁迫限制了它们的生长，甚至导致它们死亡。在农业方面，极端温度、高盐干旱和病原体袭击等环境压力是造成产量损失的主要原因，它们使世界范围内的作物性能下降到其遗传潜力的20%左右。这一问题因全球气候变化和天气波动而进一步恶化，这必然会大大增加生产的不稳定性，并使自然资源退化。为了应对农业生产的这些主要制约因素，开发能够耐受环境胁迫的作物，从而确保在恶劣条件下的生产力，对植物研究人员来说已经变得至关重要。为了实现这一重要的长期目标，研究适应不同环境胁迫的野生物种，如模式植物拟南芥（Arabidopsis thaliana），对于提供遗传资源和拓宽栽培作物狭窄的遗传基础至关重要。此外，通过培育抗逆性性状来增强抗逆性还需要详细了解各种基因和蛋白质在胁迫期间细胞膜损伤控制中的作用，这是植物抗逆性所需的第一个细胞反应之一。

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.