Charting the protein modifications systems that underpin submergence tolerance in rice

气候变化模型预测，北方欧洲和亚洲的大片地区可能在未来50年内经历洪水。目前，洪水影响了亚洲2000万公顷的水稻种植。为了稳定作物产量，必须提高谷类和蔬菜作物承受部分至全部淹没的能力。这对于水稻是可行的，因为鉴定了SUBMERGENCE 1A基因（SUB 1A，（编码第VII组乙烯反应因子[ERFVII]转录因子）），提供了对完全淹没超过7天的耐受性。SUB 1A的分子特征已经开始为植物有效的淹没生存策略的分子，生理和发育过程提供新的见解。虽然SUB 1A对于确保世界上广大洪水易发地区的水稻产量很重要，但由于亚洲各地的极端洪水事件，最近淹没的频率和程度增加，对SUB 1A的功效产生了负面影响。迫切需要新的知识和资源来提高SUB 1A在调节洪水耐受性方面的功效。最近的证据表明，SUB 1A渗入系的耐水淹水平的差异可能是由于影响SUB 1A活性的转录或转录后机制。我们的初步证据表明，SUB 1A蛋白的稳定性可能是介导水稻延长耐淹性的关键。项目合作伙伴已经发现，SUB 1A蛋白的稳定性（因此活性）受到两种主要的翻译后机制的影响，泛素化和SUMO化。通过利用这一新知识，我们的目标是为开发新的水稻品种铺平道路，其中SUB 1A蛋白在长时间淹水期间更稳定和活跃，产生增强的耐淹性，从而提高产量的稳定性。该提案还旨在利用项目合作伙伴对翻译后机制（PTM）的独特见解和世界领先地位，包括基于N端规则的泛素化和SUMO化，以确定控制植物淹没反应的新分子调节剂。这可能会导致新一代耐淹作物品种的开发。操纵控制SUB 1A稳定性的蛋白质修饰可以导致水稻延长的耐淹性。2.蛋白质修饰系统可以用来鉴定水稻耐淹涝性的新调节因子。这两个假设将在三年的项目中通过三个主要目标进行验证。探讨影响SUB 1A稳定性和翻译后状态的分子和环境因素之间的相互作用。2.测试操纵SUB 1A稳定性调节组分的转基因水稻对多种非生物胁迫的耐淹性和（时间允许的话）交叉耐受性。3.通过利用初步数据发现新的耐淹调节剂，这些数据表明存在影响植物存活的新靶点，并在淹水诱导的缺氧过程中经历N-末端规则介导的泛素化和SUMO化。Timeland：我们的初步观察表明，翻译后修饰对SUB 1A功能至关重要，这为提高水稻耐淹性提供了一个非常新颖的分子解释和管道。在控制SUB 1A和定义新的监管机构的淹没与解决分子机制的PTM的作用的表征将提供新的方法，提供强大的洪水和更广泛的非生物胁迫耐受性的植物。

Climate change models predict that large areas of Northern Europe and Asia is likely to experience flooding in the next 50 years. Currently flooding affects rice cultivation across 20 million hectares in Asia. To stabilize crop yields it is imperative to increase the capacity of cereal and vegetable crops to endure partial to complete submergence. This has been feasible for rice, due to the identification of the SUBMERGENCE 1A gene (SUB1A, (encoding a group VII ETHYLENE RESPONSE FACTOR [ERFVII] transcription factor) providing tolerance to complete submergence for over 7 days. The molecular characterization of SUB1A has begun to provide new insights into molecular, physiological and developmental processes that underlie an effective submergence survival strategy in plants. While SUB1A is important to ensure rice productivity in vast flood prone areas of the world, recent increases in frequency and magnitude of submergence due to extreme flooding events across Asia has negatively impacted SUB1A efficacy. New knowledge and resources are urgently needed that can boost SUB1A efficacy in mediating flooding tolerance. Recent evidence indicates that a difference in levels of flooding tolerance of SUB1A introgressed lines may be due to either transcriptional or post-transcriptional mechanisms that affect SUB1A activity. Our preliminary evidence suggests that the stability of the SUB1A protein is likely to be critical in mediated prolonged submergence tolerance in rice.The project partners have discovered that SUB1A protein stability (and therefore activity) is affected by two major post-translational mechanisms, ubiquitylation and SUMOylation. By exploiting this new knowledge we aim to pave the way to develop new rice varieties in which the SUB1A protein is more stable and active during prolonged flooding, generates enhanced submergence tolerance and therefore greater stability of yield. This proposal also aims to exploit the project partners unique insight and world leads into post-translational mechanisms (PTMs), including N-end rule based Ubiquitylation and SUMOylation, to identify new molecular regulators that control submergence response in plants. This could lead the development of a new generation of flooding tolerant crop varieties.Overarching hypotheses of the proposal: 1. Manipulating protein modifications that govern SUB1A stability can lead to extended flooding tolerance in rice. 2. Protein modification systems can be exploited to identify new regulators of submergence tolerance in rice.These 2 hypotheses will be tested by 3 main objectives within the 3 year project.1. To investigate the interaction between the molecular and environmental factors that affect SUB1A stability and posttranslational state. 2. To test for submergence tolerance and (time permitting) cross-tolerance to multiple abiotic stresses in transgenic rice plants that manipulate the regulatory components of SUB1A stability. 3. Discover novel regulators of flooding tolerance by exploiting preliminary data that indicates the presence of new targets that affects plant survival and undergo both N-end rule mediated Ubiquitylation and SUMOylation during submergence induced hypoxia.Timeliness: Our preliminary observations demonstrating that posttranslational modifications are essential for SUB1A function provide a highly novel molecular explanation and conduit to enhanced flooding tolerance in rice. Characterization of the role of the PTMs in controlling SUB1A and definition of new regulators of submergence with solved molecular mechanisms will offer novel approaches for delivery of plants with robust flooding and wider abiotic stress tolerance.