NSF-ANR MCB/PHY: Elucidating Plant Vascular Function and Dynamics in Planta and on Chip

维管植物的功能依赖于通过两个耦合维管系统驱动的主动和被动运输现象：蒸腾作用通过木质部将水分从根输送到叶中，以维持水合作用和转移营养物质，渗透作用通过韧皮部将叶片光合合成的糖输送到整个植物中进行生长和储存。这两种流动也被假设为介导植物内部的远距离生化信号，协调整个植物的功能，并代表可持续农业作物改良的重要目标。该项目将物理化学、设备工程和植物生物学方面的专业知识结合起来，开发新的工具来询问这些过程，并对它们进行新的基本生物物理和生物学理解。关于这些运输过程的生理机制和功能作用，特别是与韧皮部及其与木质部和其他组织的耦合有关的许多基本问题仍然存在：1)糖、水和信号分子进出韧皮部的生物物理学；2)韧皮部运输作为生物（如光合速率和局部组织生长）和非生物（如水分状况的日变化）过程的函数的动态；3)这些过程在整个生物体尺度上的协调。由于缺乏实验工具来研究从局部膜介导到系统规模过程的跨尺度假设，无论是在体外还是在植物体内，这些主题的进展都受到阻碍。为了解决这些问题，一个由美国和法国研究人员组成的国际团队将共同开发第一个合成系统，该系统可以重现木质部和韧皮部系统的完整、耦合操作，以测试关于植物脉管系统机制和功能的多种生物物理假设。该团队还将开发用于感应植物内血管运输过程的新型传感器；并将体外实验与体内生物物理和生化实验联系起来。这项工作将为植物维管功能的生物学和生物物理学提供新的见解，并为其他人的基础和应用研究创造新的工具。该项目的成果将通过创造新的微流体装置和功能，新的植物内测量工具，以及对整个植物整合资源和信号的基本原理的新理解，在科学和技术上服务于更广泛的社区。这些工具和理解可以转化为作物改良和管理的战略，以及其他行业，包括制造业。这一国际性、跨学科的项目将为美法两国机构的研究生和博士后学者提供丰富的培训机会。康奈尔大学的团队将为来自服务不足社区的高中生创建和提供与该项目相关的体验课程，并通过本科生研究体验项目指导本科生暑期学生。这个美国/法国合作项目由美国国家科学基金会（NSF）和法国国家研究机构（ANR）支持，其中NSF资助美国研究人员，ANR资助法国合作伙伴。美国研究人员由数学和物理科学理事会的生命系统物理学计划和生物科学理事会的分子生物物理学计划/分子和细胞生物科学部联合资助。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。

The function of vascular plants relies both on active and passive transport phenomena driven through two coupled vascular systems: transpiration moves water from the roots to the leaves through the xylem to maintain hydration and transfer nutrients, and osmosis drives the flow through the phloem carrying photosynthesized sugars from the leaves throughout the plant for growth and storage. Both flows are also hypothesized to mediate long-distance biochemical signaling within the plant that coordinate whole-plant function and represent important targets for crop improvement for sustainable agriculture. This project unites expertise on physicochemistry, device engineering, and plant biology to develop new tools for interrogating these processes and new fundamental biophysical and biological understanding of them. Many fundamental questions remain on the physiological mechanisms of operation and functional roles of these transport processes, particularly relative to the phloem and its coupling to the xylem and other tissues: 1) the biophysics of the loading and unloading of sugars, water, and signaling molecules to and from the phloem; 2) the dynamics of phloem transport as a function of biotic (e.g., photosynthetic rate and localized tissue growth) and abiotic (e.g., diurnal variations in water status) processes; and 3) the coordination of these processes at the whole-organism scale. Progress on these topics has been hindered by the lack of experimental tools with which to investigate hypotheses across scales, from local membrane-mediated to system-scale processes, either in vitro or in planta. To address these questions, an international team of researchers in the USA and France will work together to develop the first synthetic system that allows for recapitulation of the full, coupled operation of the xylem and phloem systems to test a diversity of biophysical hypotheses on the mechanisms and function of plant vasculature. The team will also develop new sensors for sensing of vascular transport processes, in-plant; and inform and confront in vitro experiments with biophysical and biochemical experiments in vivo. This effort will provide new insights into the biology and biophysics of plant vascular function and create new tools for basic and applied research by others.The outcomes of this project will serve the broader community scientifically and technologically by creating new microfluidic devices and functionalities, new tools for in-plant measurement, and new understanding of the fundamentals of whole-plant integration of resources and signals. These tools and understanding could translate into strategies for crop improvement and management, as well as into other industries, including manufacturing. This international, cross-disciplinary project will provide rich training opportunities to graduate students and post-doctoral scholars at both institutions in the US and France. The Cornell-based team will create and deliver experiential curriculum related to this project for high school students from underserved communities and mentor undergraduate summer students through Research Experience for Undergraduates programs on these research themes. This collaborative US/France project is supported by the US National Science Foundation (NSF) and the French Agence Nationale de la Recherche (ANR), where NSF funds the US investigators and ANR funds the partners in France. The US investigators are jointly funded by the Physics of Living Systems program in the Directorate for Mathematical and Physical Sciences and the Molecular Biophysics program/Division of Molecular and Cellular Biosciences in the Directorate for Biological Sciences.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.