Collaborative Research: RESEARCH-PGR: Unraveling the origin of vegetative desiccation tolerance in vascular plants

气候变化正在增加世界各地干旱事件的频率和严重程度，导致作物生产力遭受重大损失，影响未来的粮食安全。因此，培育抗旱能力更强的作物是育种家、科学家和政府的迫切需要。对大多数植物来说，过多的水分流失是致命的，但有一些植物，被称为复活植物，具有几乎完全脱水的绿色组织存活的非凡能力。这种能力，被称为营养性干燥耐受性（VDT），依赖于分子过程的组合，使植物在干燥状态下保持其生存能力。有趣的是，所有与VDT相关的基因也存在于干燥易感植物中，因为大多数植物产生的种子可以在干燥状态下存活很长一段时间，而不会失去浇水后发芽的能力。因此，耐受性和易感性植物之间的区别一定在于它们激活保护绿色组织细胞免受干燥的机制的能力，而不仅仅是在种子中。该项目的目的是确定植物如何进化以激活营养组织和生殖组织的干燥耐受性的机制。具体地说，本研究旨在确定作为干燥耐受性的主要调节因子的基因。该合作项目将采用多学科方法，通过比较绿色组织和种子的动态响应来确定共同和特定的分子过程。该项目的结果将有助于设计分子育种方案，以提高作物对气候变化的适应能力。对大多数植物来说，过多的水分流失是致命的，但少数物种，即所谓的复活植物，进化出了在几乎完全干燥的环境中生存的非凡能力。这种能力被称为干燥耐受性（DT），它依赖于生理、生化和分子反应的结合，使植物能够在干燥状态下保持细胞的完整性。有趣的是，所有与营养性干燥耐受性（VDT）相关的基因家族都存在于对干燥敏感的植物中，这表明这种性状主要是通过协调DT基因表达的调控网络的变化而不是通过获得新基因而进化的。由于缺乏准确的比较分析，阻碍了VDT调控因子的鉴定和维管植物中该性状进化起源的研究。因此，本合作项目将利用综合方法分析关键复活谱系的DT响应，确定控制VDT的调控网络，并推断其在维管植物进化过程中的起源。具体目标包括(1)确定DT过程中营养和生殖组织的整体转录变化动力学，(2)对DT过程中营养和生殖组织的整体代谢变化进行动力学分析，(3)对脱水和恢复过程中营养组织的转录和代谢组学变化进行原位和单细胞型动力学分析。(4)对复活植物中控制DT的调控网络进行比较分析。本研究将确定激活VDT所需的遗传代谢网络，为未来作物选育增强耐旱性提供基础。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。

Climate change is increasing the frequency and severity of drought events around the world, leading to major losses in crop productivity, which affect future food security. Consequently, the generation of crops with enhanced drought tolerance represents an urgent need for breeders, scientists, and governments. Excessive water loss is lethal for most plants, but a few plants, known as resurrection plants, have the remarkable ability to survive almost complete dehydration of their green tissues. This ability, known as vegetative desiccation tolerance (VDT), relies upon a combination of molecular processes that allow the plant to maintain its viability in the dry state. Interestingly, all genes involved in VDT are also present in desiccation-susceptible plants, as most plants produce seeds that can survive for long periods in the dry state without losing the capacity to germinate upon watering. Therefore, the difference between tolerant and susceptible plants must be in their capacity to activate the mechanisms that protect cells against desiccation in green tissues and not only in the seed. The objective of this project is to identify the mechanisms of how plants evolved to activate desiccation tolerance in both vegetative and reproductive tissues. Specifically, this study seeks to identify the genes that act as master regulators of desiccation tolerance. This collaborative project will use a multidisciplinary approach to identify common and specific molecular processes by comparing the dynamic responses of green tissues and seeds. The results of this project will serve to design molecular breeding schemes for improving crop resilience to climate change.Excessive water loss is lethal for most plants, but a few species, known as resurrection plants, evolved the remarkable ability to survive almost complete dryness. This ability, known as desiccation tolerance (DT), relies upon a combination of physiological, biochemical, and molecular responses that allow the plant to preserve cell integrity in the dry state. Interestingly, all gene families involved in vegetative desiccation tolerance (VDT) are present in desiccation-sensitive plants, suggesting that this trait evolved primarily by changes in the regulatory networks coordinating the expression of DT genes rather than from the acquisition of new genes. The lack of accurate comparative analyses has hindered the identification of the regulators controlling VDT and the study of the evolutionary origin of this trait in vascular plants. Therefore, this collaborative project will determine the regulatory networks controlling VDT and infer its origin during vascular plant evolution by analyzing the DT response of key resurrection lineages using integrative methodologies. Specific objectives include (1) determining the kinetics of the global transcriptional changes in vegetative and reproductive tissues during the DT process, (2) performing kinetic analyses of the global metabolic changes in vegetative and reproductive tissues during the DT process, (3) performing in situ and single-cell type kinetic analysis of transcriptional and metabolomic changes of vegetative tissues during dehydration and recovery, and (4) conducting comparative analyses of the regulatory networks controlling DT in resurrection plants. This study will identify genetic-metabolic networks required to activate VDT, providing the basis for future crop breeding of enhanced drought tolerance.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.