Plastid terminal oxidase - a route to improving food security

人类在21世纪面临的最重要的挑战是，在人类活动，特别是燃烧化石燃料引起气候变化的背景下，确保不断增长的世界人口能够继续以可靠的方式获得食物。农作物特别容易受到天气条件波动的影响，干旱、热浪和洪水等事件都可能导致产量下降。随着未来此类天气事件的增加，我们迫切需要培育具有更大耐受能力的植物。光合作用过程是植物与环境相互作用的最前沿。植物利用叶绿素分子吸收光能，并利用这种能量制造糖来喂养植物。极端天气不会阻止光被吸收，但它可以阻止它被使用。当这种情况发生时，未使用的能量反而会对叶子造成损害。特别是，它可以引起高活性分子的形成，如漂白剂过氧化氢。如果不加以控制，这些光会破坏叶子。这个项目的目的是研究一种新的机制，保护植物免受过量的光。我们一直在研究一种叫做盐芥（Eutrema salsugineum）的植物，它是一种生长在盐沼中的植物。盐芥是重要作物如卷心菜和油料作物的近亲。我们已经在这种植物中鉴定出一种称为质体末端氧化酶（Plastid Terminal Oxidase，简称PTOX）的蛋白质，我们已经证明它可以作为光合作用的安全阀，在不能使用时耗散多余的光能。因此，PTOX具有改善作物植物的胁迫耐受性的潜力。然而，当我们从盐芥中提取PTOX基因并将其转移到另一个物种时，我们无法检测到任何活性。我们最近表明，活动需要在叶细胞中的PTOX蛋白的本地化的变化，移动到一个不同的隔室，它以前没有被seed.The项目的目的是了解在Eutrema中的PTOX的重新定位所涉及的过程，并试图将这些转移到另一个物种。我们将使用最先进的蛋白质和基因表达分析的组合，结合电子显微镜和基因工程来验证移动PTOX所涉及的机制，并确定可能需要的新基因。在项目结束时，我们将收集新的信息来定义所涉及的过程，并将测试某些基因，看看它们是否在PTOX的激活中发挥作用。

The most important challenge facing humanity in the 21st century ensuring that the growing world population can continue to be fed in a reliable way, against a backdrop of changes in climate induced by human activities, especially the burning of fossil fuels. Crops are especially vulnerable to fluctuations in weather conditions, with events such as droughts, heat waves and floods all liable to reduce yields. As such weather events are expected to increase in the future, we urgently need to breed plants with a greater capacity to tolerate these.The process of photosynthesis is at the forefront of plant interactions with their environment. Plants absorb light energy using molecules called chlorophylls, and use that energy to make sugars which feed the plant. Extreme weather does not stop light being absorbed, but it can stop it being used. When this occurs, the unused energy can instead cause damage to the leaf. In particular, it can give rise to the formation of highly reactive molecules, such as the bleach hydrogen peroxide. These can, if not controlled, destroy the leaf.The aim of this project is to investigate a new mechanism which protects plants from excess light. We have been working with a plant called salt cress (Eutrema salsugineum) which is a species found growing salt marshes. Salt cress is a relative of important crop plants such as cabbage and oil seed. We have identified a protein in this plant called the Plastid Terminal Oxidase (or PTOX for short) which we have shown can act as a safety valve for photosynthesis, dissipating excess light energy, when this cannot be used. PTOX has the potential therefore to improve stress tolerance in crop plants. When we take the gene for PTOX from salt cress and transfer it to another species, however, we are unable to detect any activity. We have recently shown that activity requires a change in the localisation of the PTOX protein in the leaf cells, moving it to a different compartment where it has not previously been seen.The aim of this project is to understand the processes involved in the relocalisation of PTOX in Eutrema and to attempt to transfer these to another species. We will use a combination of state of the art protein and gene expression analysis, combined with electron microscopy and genetic engineering to characterise the mechanisms involved in moving PTOX and to identify new genes which maybe required for this. At the end of the project we will have gathered new information to define the processes involved and will have tested certain genes to see if they play a role in the activation of PTOX.