Inducing Plastid Terminal Oxidase for Photoprotection

诱导质体末端氧化酶进行光保护

• 批准号: BB/X006905/1
• 负责人: Giles Johnson
• 金额: $ 73.57万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FX006905%2F1
• 关键词: Inducing; Plastid; Terminal; Oxidase; Photoprotection

Food security is one of the greatest challenges facing humanity. Growing populations and changing diets are increasing food demand at a time when human-induced climate change is making weather less predictable, threatening crop production. Episodes of drought, flooding, high and low temperatures, even for relatively short periods, can all undermine final crop yields. Against this background, there is an urgent need to breed crops which combine high productivity with the ability to tolerate environmental stress.One of the main primary targets of environmental stress is photosynthesis. Photosynthesis is the process by which plants capture light energy and use that energy to fix carbon dioxide from the air, producing sugars. Photosynthesis is the ultimate source of all the food we eat. When plants are stressed, imbalances can occur between the amount of energy a leaf absorbs and the amount that can be used in photosynthesis. When this happens, the excess energy can result in the production of harmful molecules called reactive oxygen species (ROS; including for example the bleach, hydrogen peroxide). These ROS can damage the cell, destroying membranes, proteins and DNA.AAcross the plant kingdom we see a range of mechanisms that help protect plants from ROS. Plants contain high concentrations of antioxidants, such as Vitamins A and E, which are essential components of the human diet. They also possess regulatory mechanisms that prevent ROS production. One example, so far only seen naturally in a handful of extreme stress tolerant plants, is called the Plastid Terminal Oxidase, or PTOX. In stress tolerant plants, such as the cabbage relative salt cress (Eutrema salsugineum, in the brassica family), PTOX acts as a safety valve for photosynthesis, dissipating excess energy harmlessly as water, avoiding ROS production. PTOX has not however been seen in common crop species. Previous attempts to use genetic modification to induce PTOX in other species have not only failed, they have made matters worse, increasing rather than preventing stress.In a recent breakthrough, we have shown it is possible to induce activity of PTOX in a new species, by targeting the protein to a particular cellular compartment called the thylakoid lumen. Lumen-targeted PTOX is not constitutively active, but becomes active under stress conditions. We have shown that this activity, seen previously in salt cress, can be transfered to another brassica species, thale cress. In this grant, we will examine the factors that are necessary for the stress-induced activation of lumen-targeted PTOX. We will also attempt, using the same approach, to induce PTOX in important crop species - oilseed rape (another brassica), soybean (a legume) and wheat and barley (grasses). If successful, this approach will pave the way to generate crop plants with improved stress tolerance, increasing crop yields under extreme environmental conditions.

粮食安全是人类面临的最大挑战之一。在人类引起的气候变化使天气降低而威胁农作物产量的情况下，人口不断增长和饮食不断变化正在增加粮食需求。干旱，洪水，高温和低温的发作，即使在相对较短的时间内也可能破坏最终作物产量。在这种背景下，迫切需要繁殖农作物，将高生产率与耐受环境压力的能力相结合。环境压力的主要主要目标之一是光合作用。光合作用是植物捕获光能并利用该能量来固定空气中二氧化碳的过程，产生糖。光合作用是我们吃的所有食物的最终来源。当植物受到压力时，叶子吸收的能量量与可在光合作用中使用的量之间可能发生不平衡。当发生这种情况时，多余的能量会导致产生称为活性氧的有害分子（ROS；例如漂白剂，过氧化氢）。这些ROS会损坏细胞，破坏膜，蛋白质和DNA。植物含有高浓度的抗氧化剂，例如维生素A和E，它们是人类饮食的重要组成部分。它们还具有防止ROS产生的调节机制。一个例子，到目前为止，只有在少数极端耐受性的植物中自然看到，称为质体末端氧化酶或PTOX。在压力耐受植物中，例如卷心菜相对盐奶油（在甘蓝家族中的Eutrema salsugineum）中，PTOX充当光合作用的安全阀，随着水而无害地消散了多余的能量，避免了ROS产生。然而，在普通农作物物种中尚未看到PTOX。以前尝试使用遗传修饰来诱导其他物种中的PTOX的尝试不仅失败了，而且使事情变得更糟，增加而不是预防压力。在最近的突破中，我们已经证明，可以通过将蛋白质靶向新物种中的PTOX活性，将蛋白质靶向特定的细胞隔室，称为Thylakoid。靶向流明的PTOX不是组成型活跃的，而是在应力条件下变得活跃。我们已经表明，这种活动以前在盐分中可以看到，可以转移到另一种甘蓝物种Thale Cress。在这笔赠款中，我们将研究压力诱导的靶向PTOX的激活所必需的因素。我们还将尝试使用相同的方法来诱导重要的农作物物种 - 油籽强奸（另一种Brassica），大豆（豆类）以及小麦和大麦（草）。如果成功，这种方法将为产生具有提高胁迫耐受性的作物植物铺平道路，在极端环境条件下增加农作物的产量。