ERA-CAPS: Mechano-purino signaling in abiotic stress

为了生存，植物必须在风面前保持直立的茎，而它们的根必须在土壤坚硬和压实的情况下寻找水分和养分。风在茎中诱导适应性的结构变化，如次生加厚。当感觉到障碍时，根就会穿透坚硬的底物，并改变它们的生长和结构。尽管有这种适应能力，但机械压力极大地导致了每年的作物损失和产量下降，随着气候的变化和越来越多的暴风雨和反复无常的天气，这些问题可能会恶化。因此，确定机械感应和信号传递的组成部分是作物改良的优先事项。这个项目探索了三磷酸腺苷(ATP)，通常被认为是细胞内的能量来源，作为响应机械应力(例如，风)的细胞外信号的作用。参与其中的三个小组在植物信号研究，特别是与细胞外ATP相关的研究，以及植物如何响应机械胁迫的研究方面拥有特定的专业知识。该项目在可持续农业方面是相关和及时的；迫切需要适应能力更强的作物，但关于植物如何承受机械压力的信息很少。这项研究将确定茎和根分别对风和土壤硬度做出反应的新成分，有助于作物在倒伏、抗风和穿透性根生长方面的改良计划。除了有助于水分和养分的吸收，更深的根和更多的侧向延伸改善了土壤结构，从而改善了水分和养分的保持。风灾还会对林业和城市景观造成损失。该项目将为了解植物对机械应力的适应性和提高作物产量以适应日益增长的全球人口提供基础。最近的证据表明，植物中的机械生物学和嘌呤能信号之间存在交叉。嘌呤能信号转导是由细胞外的嘌呤核苷酸，如三磷酸腺苷，引起的信号转导。具体地说，细胞外ATP(EATP)已被发现随着细胞扩张而增加(这是一个产生内在机械应力的过程)，eATP也随着外部机械应力的增加而增加。此外，eATP影响根的发育，并调控作为最严重的机械胁迫的创伤的转录反应。最近发现的植物Purino受体，拟南芥DORN1，为在分子和整个植物水平上探索Purino和机械信号之间的关系提供了一个独特的机会。关键是，DORN1的结构表明它是细胞壁状态的报告分子。在这个项目中，两个跨学科的嘌呤信号传递小组(Stacey和Davies)和一个机械生物学小组(Moulia)将使用分子、生物化学和生物物理方法描绘DORN1机制Purino信号系统。将探索DORN1的结构-功能关系，以确定它与壁上的附着如何调节其eATP结合活性。细胞膜钙通道介导DORN1依赖的根和茎中钙离子增加的特征将被描述。表型突变体将决定DORN1及其下游的钙离子通道对树干姿态控制、对风的适应性反应、根钙反应和机械调节生长的影响。这项研究的结果对农业和社会很重要，因为在拟南芥中获得的结果可以转化为作物。了解植物墙如何应对机械压力将为克服作物倒伏和提高作物对环境挑战的适应能力提供一个平台。结合对学生进行跨学科科学培训，项目成果将有助于食品和国家安全。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

To survive, plants must maintain an upright stem in the face of wind, while their roots must forage for water and nutrients despite soil hardness and compaction. Wind induces adaptive, structural changes in stems, such as secondary thickening. Roots penetrate hard substrate and modify their growth and architecture as obstacles are sensed. Despite this ability to adapt, mechanical stresses contribute significantly to annual crop loss and decreased yield, problems likely to worsen with changing climate and increasingly stormy and erratic weather. Therefore, identifying the components of mechano-sensing and signaling is a priority for crop improvement. This project explores the role of adenosine triphosphate (ATP), generally known as an intracellular energy source, as an extracellular signal in response to mechanical stress (e.g., wind). The three groups involved have specific expertise in studies of plant signaling, especially related to extracellular ATP, as well as studies of how plants respond to mechanical stress. This project is relevant and timely regarding sustainable agricultural; better adapted crop plants are needed urgently but there is little information on how plants withstand mechanical stress. The research will identify new components of how stems and roots respond to wind and soil hardness, respectively, helping crop improvement programs for lodging, wind resistance and penetrative root growth. In addition to aiding water and nutrient uptake, deeper roots with more lateral outgrowth improve soil structure, thus improving water and nutrient retention. Wind damage also inflicts losses on forestry and urban landscapes. This project will provide foundational understanding on the adaptability of plants to mechanical stress and for improving crop yield for the increasing global population. Recent evidence points to an intersection between mechanobiology and purinergic signaling in plants. Purinergic signaling is the transduction of signals elicited by extracellular purine nucleotides, such as ATP. Specifically, extracellular ATP (eATP) has been found to increase as cells expand (a process that generates intrinsic mechanical stress) and eATP also increases in response to extrinsic mechanical stress. Moreover, eATP affects root development and governs the transcriptional response to wounding as the most severe mechanical stress. The recently discovered plant purino receptor, Arabidopsis DORN1, provides a unique opportunity to explore at the molecular and whole plant levels the relationships between purino- and mechano-signalling. Critically, the structure of DORN1 indicates it serves as a reporter of cell wall state. In this project, two, cross-disciplinary purino-signalling groups (Stacey and Davies) and a mechanobiology group (Moulia) will delineate the DORN1 mechano-purino signaling system using molecular, biochemical and biophysical approaches. Structure-function relationships of DORN1 will be probed to determine how its attachment to the wall can regulate its eATP binding activity. The cell membrane Ca2+ channels mediating the DORN1-dependent Ca2+ increase in roots and stems will be characterized. Phenotyping mutants will determine the impact of DORN1 and downstream Ca2+ channels on stem posture control, adaptive response to wind, root Ca2+ response and mechano-regulated growth. Outcomes of the research is important to agriculture and society because the results obtained in Arabidopsis can be translated to crops. Understanding how plant walls cope with mechanical stresses will provide a platform to overcome crop lodging and increasing crop resilience to environmental challenges. Combined with training students in interdisciplinary science, the project outcomes will contribute to food and national security.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.