Collaborative Research: Ecological Physiology of Plant Chloroplast Small Heat-Shock Proteins

热休克蛋白(HSPs)是几乎所有生物体在应对大多数环境和生物应激时产生的一种通用应激蛋白，被认为在应激过程中保护细胞免受损伤或促进恢复。热休克蛋白的细胞数量或生化效率的变化的重要性尚不清楚，特别是对植物和被称为低分子量或“小”热休克蛋白的类别。由于缺乏针对特定热休克蛋白的合适的生物分子探针以及实验操作和评估热休克蛋白变异影响的方法，对热休克蛋白的研究进展一直受到阻碍。PI已经开发出针对叶绿体中的小热休克蛋白(植物光合作用发生的细胞室)的分子探针，以及评估热休克蛋白有效性的方法。利用这些工具，他们已经证明，叶绿体小热休克蛋白通过保护光合作用中对胁迫敏感的关键步骤(光系统II中的电子传递)，在高温和其他环境胁迫下保护光合作用。然而，植物中叶绿体小分子热休克蛋白在逆境中保护光合作用的能力的差异，如耐热野生植物和热敏感作物之间的预测差异，还没有被检验。在这一系列研究中，PI将检测胁迫敏感和耐逆野生植物中的叶绿体小分子热休克蛋白，以确定它们在细胞数量和生化效率方面的差异，以及这如何影响热胁迫下光合作用的保护。这将是第一次对核电站热休克蛋白进行这样的调查。他们将探索一系列物种中小分子热休克蛋白的分子和生化变化，他们将检查小热休克蛋白含量与植物表现之间的相关性，并将使用从一系列物种中纯化的热休克蛋白进行体外实验，以确定叶绿体小热休克蛋白的质量和数量变化如何影响其保护功能。这些结果将有助于理解影响自然界植物抗逆性的因素，并有助于理解在农业研究中可能有用的因素。鉴于叶绿体小分子热休克蛋白在许多逆境中保护光合作用的重要性，光合作用在植物中的中心作用，以及光合作用对环境胁迫的高度敏感性，这些结果应该对生物工程和培育更耐受逆境的作物特别有用。

Heat-shock proteins (Hsps) are types of general stress proteins produced by virtually all organisms in response to most environmental and biological stresses, and are thought to protect cells from damage during stress or facilitate recovery. The importance of variation in the cellular quantity or biochemical efficiency of Hsps is unknown, particularly for plants and for the category of Hsps referred to as the low-molecular-weight or "small" Hsps. Progress in understanding Hsps has been hampered by the lack of appropriate biomolecular probes for specific Hsps and methods to experimentally manipulate and assess the effect of variation in Hsps. The PIs have developed molecular probes specific to the small Hsps in chloroplasts, the cell compartment where photosynthesis takes place in plants, as well as assays to assess Hsp effectiveness. Using these tools, they have shown that chloroplast small Hsps protect photosynthesis during heat and other environmental stresses, by protecting a key stress-sensitive step of photosynthesis (electron transport in Photosystem II). However, differences among plants in the ability of chloroplast small Hsp to protect photosynthesis during stress, such as predicted differences between heat-tolerant wild plants and heat-sensitive crops, have not been examined.In this series of studies, the PIs will examine chloroplast small Hsps in stress-sensitive vs. stress-tolerant wild plants to determine how they differ in the cellular quantity and biochemical efficiency of small Hsps and how this affects the protection of photosynthesis during heat stress. This would be the first such investigation for plant Hsps. They will explore molecular and biochemical variation in small Hsps across a range of species, they will examine correlations between small Hsp content and plant performance, and they will carry out experiments in vitro, using Hsps purified from a range of species, to determine how qualitative and quantitative variation in chloroplast small Hsps affects their protective function. These results will contribute both to understanding factors that affect stress-tolerance of plants in nature and to understanding factors that may be useful in agricultural research. Given the importance of chloroplast small Hsps in protecting photosynthesis during many stresses, the central role of photosynthesis in plants, and the high sensitivity of photosynthesis to environmental stress, the results should be especially useful for the bioengineering and breeding of more stress-tolerant crops.