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，导致作物产量的重大损失，从而影响未来的粮食安全。因此，具有更强抗旱性的作物的产生对育种者、科学家和政府来说是迫切需要的。对于大多数植物来说，过多的水分流失是致命的，但有几种植物，即所谓的复活植物，在绿色组织几乎完全脱水的情况下具有非凡的生存能力。这种能力被称为营养脱水耐受性(VDT)，它依赖于一系列分子过程的组合，使植物在干燥状态下保持其生存能力。有趣的是，所有涉及VDT的基因也存在于干燥敏感的植物中，因为大多数植物产生的种子可以在干燥状态下长时间存活，而不会失去在浇水时发芽的能力。因此，耐受植物和敏感植物之间的区别必须在于它们激活保护绿色组织中的细胞免受干燥的机制的能力，而不仅仅是在种子中。该项目的目标是确定植物如何进化以激活营养组织和生殖组织中的脱水耐受性的机制。具体地说，这项研究试图确定对脱水耐受性起主要调节作用的基因。这个合作项目将使用多学科方法，通过比较绿色组织和种子的动态反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计划，以提高作物对气候变化的适应能力。过度失水对大多数植物来说是致命的，但少数物种，即复活植物，进化出了在几乎完全干旱的情况下生存的非凡能力。这种能力被称为脱水耐受性(DT)，依赖于生理、生化和分子反应的组合，使植物在干燥状态下保持细胞的完整性。有趣的是，所有参与营养脱水耐受(VDT)的基因家族都存在于对脱水敏感的植物中，这表明这一特性主要是通过协调DT基因表达的调控网络的变化而进化的，而不是通过获得新的基因。缺乏准确的比较分析阻碍了控制VDT的调控因子的鉴定和维管植物这一性状的进化起源的研究。因此，该合作项目将确定控制VDT的调控网络，并通过使用综合方法分析关键的复活谱系的DT响应来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过程中营养组织和生殖组织的全球转录变化的动力学；(2)动态分析DT过程中营养组织和生殖组织的全球代谢变化；(3)原位和单细胞类型动力学分析营养组织在脱水和恢复过程中的转录和代谢变化；以及(4)对复活植物中控制DT的调控网络进行比较分析。这项研究将确定激活VDT所需的遗传-代谢网络，为未来增强抗旱性的作物育种提供基础。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。

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.