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。在人为引起的气候变化使天气变得更加不可预测并威胁农作物生产的同时，人口的增长和饮食的变化正在增加粮食需求。干旱、洪水、高温和低温，即使持续时间相对较短，也会损害最终作物产量。在此背景下，迫切需要培育兼具高生产力和耐受环境胁迫能力的作物。环境胁迫的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固定空气中的二氧化碳并产生糖的过程。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，叶子吸收的能量与可用于光合作用的能量之间可能会出现不平衡。当这种情况发生时，多余的能量会导致产生称为活性氧（ROS；包括漂白剂、过氧化氢）的有害分子。这些 ROS 会损害细胞，破坏细胞膜、蛋白质和 DNA。在整个植物界，我们看到了一系列有助于保护植物免受 ROS 侵害的机制。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。它们还拥有阻止 ROS 产生的调节机制。其中一个例子被称为质体末端氧化酶（PTOX），迄今为止仅在少数耐极端胁迫的植物中天然存在。在耐胁迫植物中，例如卷心菜相关的盐水芹（Eutrema salsugineum，属于芸苔科），PTOX充当光合作用的安全阀，以水的形式无害地消散多余的能量，避免ROS的产生。然而，在常见作物品种中尚未发现 PTOX。以前尝试使用基因改造在其他物种中诱导 PTOX 的尝试不仅失败了，而且还使事情变得更糟，增加而不是预防压力。在最近的突破中，我们已经证明在新物种中诱导 PTOX 活性是可能的，通过将蛋白质靶向称为类囊体腔的特定细胞区室。流明靶向 PTOX 不是固有活性的，但在压力条件下变得活跃。我们已经证明，以前在盐水芹中观察到的这种活性可以转移到另一种芸苔属植物——拟南芥中。在这笔资助中，我们将研究压力诱导流明靶向 PTOX 激活所需的因素。我们还将尝试使用相同的方法，在重要的作物物种中诱导 PTOX——油菜（另一种芸苔属植物）、大豆（一种豆科植物）以及小麦和大麦（草类）。如果成功，这种方法将为培育具有更高抗逆性的作物铺平道路，从而提高极端环境条件下的作物产量。