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

热休克蛋白（Heat-shock Proteins，Hsps）是一种由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般应激蛋白，被认为在应激过程中保护细胞免受损伤或促进恢复。 Hsps的细胞数量或生化效率的变化的重要性是未知的，特别是对于植物和被称为低分子量或“小”Hsps的Hsps类别。 由于缺乏针对特定Hsps的合适的生物分子探针以及实验操作和评估Hsps变异效应的方法，理解Hsps的进展受到阻碍。 研究所已经开发出针对叶绿体中小Hsps的分子探针，叶绿体是植物进行光合作用的细胞室，以及评估Hsps有效性的测定。 利用这些工具，他们已经表明叶绿体小Hsps通过保护光合作用的关键应激敏感步骤（光系统II中的电子传递）在热和其他环境胁迫期间保护光合作用。 然而，植物在胁迫期间叶绿体小Hsp保护光合作用的能力的差异，例如耐热野生植物和热敏作物之间的预测差异，尚未被研究。PI将检查压力敏感与压力下叶绿体小Hsps，耐受性野生植物，以确定它们在小Hsps的细胞数量和生化效率方面的差异，以及这如何影响热胁迫期间光合作用的保护。 这将是首次对植物Hsps进行此类调查。 他们将探索一系列物种中小热休克蛋白的分子和生化变化，他们将研究小热休克蛋白含量和植物性能之间的相关性，他们将进行体外实验，使用从一系列物种中纯化的热休克蛋白，以确定叶绿体小热休克蛋白的定性和定量变化如何影响其保护功能。 这些结果将有助于了解自然界中影响植物抗逆性的因素，并了解可能在农业研究中有用的因素。鉴于叶绿体小Hsps在许多胁迫下保护光合作用的重要性，光合作用在植物中的核心作用，以及光合作用对环境胁迫的高度敏感性，这些结果对于生物工程和更耐胁迫的作物育种特别有用。

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.