Taking a breather: Characterizing the role of H+/Ca transport in anoxia tolerance

植物经历了一个动态的环境，其中可能遇到许多压力条件。例如，淹水会引起几种压力：氧气可用性受限、温度变化、光线减少。缺氧，氧气的去除，是内涝和植物被淹没的结果。在这种胁迫下，植物组织的能量生产速率显著降低，影响了新陈代谢的许多方面。本项目研究植物细胞内钙（Ca）的波动如何影响耐缺氧性。研究人员发现，去除一种特定的钙转运体似乎可以缓冲植物对缺氧条件的影响。在这里，成像实验将从视觉上解决这种变化如何影响钙的移动，它的定位，以及钙的时空变化如何影响缺氧耐受性。为了补充这些摄影方法，生化和基因实验将解决钙运动的机制。测量蛋白质和核酸变化的方法将用于进一步确定特定钙转运体的去除如何影响植物对能量的利用。这项工作的一个广泛影响将是与休斯敦社区学院（HCC）的教师和学生开展独特的研究合作。HCC是一所开放招生的公立学校，虽然服务于美国最多样化的人群之一，但通常不提供研究经验。这些HCC学生将学习并为这个项目做出贡献。这项工作的努力将使人们更好地了解植物如何适应环境。在未来，通过工程调节植物体内钙的移动可以规避缺氧条件的不利影响，从而减轻气候变化引起的作物损失。缺氧（hypoxia）和缺氧（anoxia）是植物严重的生理胁迫。最常见的情况是，极端天气事件导致洪水泛滥，造成大面积的作物损失。膜转运蛋白可能是缺氧耐受的重要组成部分，因为它们参与了代谢过程的信号转导和调节。拟南芥液泡阳离子/质子交换器（CAXs）的突变引起对缺氧的惊人耐受性。这种健壮的表型是出乎意料的：一个功能丧失的突变导致了功能的增加。大多数CAX RNA在缺氧时是不变的，这突出了RNA谱分析作为基因发现的唯一手段的局限性。一系列的遗传学、组学、膜转运、生理学、细胞和元素成像实验将被用来表征cax在缺氧过程中的作用，这将证明它们在信号传导、阳离子转运和代谢中的作用。一个高技能，多样化的团队将使用多学科的方法，包括植物遗传学，膜运输和元素成像。作为更广泛影响的一部分，作为进一步发现的手段，休斯顿社区学院（HCC）将实施基于课程的本科生研究体验（CURE）。HCC是一所开放录取的公立学校，虽然服务于美国最多样化的人群之一，但通常不提供研究经验。简而言之，描述cax在耐缺氧中的作用将有助于更好地理解植物的信号转导。此外，这些知识最终将有助于开发抗洪作物，减少极端天气事件下的作物损失。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Plants experience a dynamic environment where numerous stress conditions may be encountered. For example, flooding induces several stresses: limited oxygen availability, changes in temperature, reduced light. Anoxia, the removal of oxygen, is a consequence of waterlogging and submergence of plants. During this stress, plant tissues significantly reduce the rate of energy production, affecting many aspects of metabolism. This project examines how fluctuations in calcium (Ca) within plant cells can impact anoxia tolerance. The investigators have discovered that removal of a specific Ca transporter appears to buffer the plant against anoxic conditions. Here imaging experiments will visually address how this change effects how Ca moves, where it is localized, and how the temporal and spatial changes in Ca can impact anoxia tolerance. To complement these photographic approaches, biochemical and genetic experiments will address the mechanisms of Ca movement. Approaches to measure changes in protein and nucleic acids will be used to further define how removal of a specific Ca transporter can impact the plant’s utilization of energy. One broad impact of this work will be the development of a unique research collaboration with faculty and students from Houston Community College (HCC). HCC is an open-admission, public school that while serving one of the most diverse populations in the US, does not usually provide research experiences. These HCC students will both learn and contribute to this project. The efforts of this work will lead to a better understanding of how plants adapt to their environment. In the future, engineering-modulated Ca movement in plants could circumvent adverse effects of anoxic conditions to mitigate climate change-induced crop loss.Oxygen deficiency (hypoxia) and absence (anoxia) are severe physiological stresses in plants. Most commonly they occur when extreme weather events lead to flooding, which causes widespread crop losses. Membrane transporters may be essential components of anoxia tolerance because they are involved in signal transduction and regulation of metabolic processes. Mutations in the Arabidopsis vacuolar cation/proton exchangers (CAXs) cause striking tolerance to anoxia. This robust phenotype was unexpected: a loss-of-function mutation causing a gain of function. The majority of CAX RNAs are unchanged during hypoxia, highlighting the limits of RNA profiling as an exclusive means of gene discovery. A series of genetic, omics, membrane transport, physiological, cell and elemental imaging experiments will be used to characterize the role of CAXs during anoxia that will demonstrate their role in signaling, cation transport and metabolism. A highly skilled, diverse team will use a multi-disciplinary approach including plant genetics, membrane transport and elemental imaging. As part of the broader impacts, and as a further means of discovery, a Course-based Undergraduate Research Experience (CURE) at Houston Community College (HCC) will be implemented. HCC is an open-admission public school that, while serving one of the most diverse populations in the US, does not typically provide research experiences. In short, characterizing the role of CAXs in anoxia tolerance will lead to a greater understanding of plant signal transduction. Furthermore, this knowledge will eventually aid in the development of flood-resistant crop plants, reducing crop loss during extreme weather events.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.