RUI: The Translocation Mechanism of Nanomaterials in Plants

纳米材料是由1-100纳米的结构组成的材料，在世界范围内用于包括医学，农业和工业在内的各个领域。这些材料在环境中具有高度反应性，并与土壤和水中的元素相互作用，影响植物和微生物的生物利用度。金属基纳米材料的小尺寸导致其被包括植物在内的生物体的高吸收率。纳米材料对生物体的影响及其毒性水平取决于各种因素，包括其大小，浓度和类型以及暴露的生物体。关于纳米材料在环境中的归宿的研究报告了植物积累纳米材料的潜力。然而，纳米材料吸收的确切机制及其在植物中的命运还没有得到很好的理解。植物中积累的纳米材料可以通过直接食用植物或通过食物链进入人体。因此，重要的是要了解它们如何与植物相互作用，以进一步保护公众健康和改善可持续农业实践。该研究项目调查了常用的金属基纳米材料银纳米颗粒在植物中的命运，以及它们与钾、镁和锌等植物必需营养素的相互作用。这将涉及一系列分子、生理和分析研究，以了解植物中银纳米颗粒的积累形式和部位，以及它们对膜转运蛋白的影响。PI将在研究期间指导本科生和硕士生，并为STEM领域代表性不足的少数民族提供教育和研究机会，包括女性，第一代大学生和有色人种。为了提高公众对纳米材料及其在植物中的命运的认识，将根据这项研究的结果创建一个三维模型，并将在当地的科学博物馆展出。纳米材料在世界范围内被用于各个领域，包括医学，农业和工业。银纳米颗粒是金属基纳米材料的常见形式。这些物质在环境中会被氧化，并转化为离子形式，这比颗粒形式更具相互作用和毒性。银纳米颗粒，无论是颗粒或离子形式，影响植物的生理和代谢在不同的水平，包括膜转运蛋白和电位，从而影响植物的水分吸收和养分转运。植物生长不需要银纳米颗粒，并且没有专门指定用于银纳米颗粒进入细胞的膜转运蛋白。然而，由于植物可以在其组织中转运和积累这些纳米颗粒，因此必须有一种转运蛋白允许这些材料穿过膜。质膜水通道蛋白和钾通道是银纳米颗粒的可能转运蛋白。一旦这些纳米颗粒被植物吸收，它们在细胞间和细胞内空间的存在就会改变细胞的电化学电位。为了提供平衡，可以影响几种膜转运蛋白的表达，包括质子ATP酶以及阳离子和阴离子通道。这反过来又影响必需营养素和水穿过膜的运动、膨压以及胞质和质外体pH水平。这一系列的事件可以影响木质部细胞的结构，并随后影响植物中必需营养物质和水分的生物积累和转运。由于水通道蛋白在水的转运、维持膨压和潜在的跨膜转运银纳米颗粒中的作用，在这项研究中，番茄（Lycopersicon esculentum）和水通道蛋白PIP 1的突变体将暴露于银纳米颗粒，以确定这些纳米颗粒在植物中的转运机制及其与植物必需营养素的相互作用。该项目将包括一系列的分析，分子和形态学分析，以实现这些目标，包括浓度，形式和银纳米粒子在植物中积累的网站，他们的曝光对膜转运的影响，以及他们的曝光对血管组织的影响。研究结果将为理解纳米材料在植物中的命运和有效利用植物进行植物修复提供信息。该奖项反映了NSF的法定使命，并被认为值得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来支持。

Nanomaterials, materials made up of structures ranging from 1-100 nanometers, are used worldwide in various sectors including medicine, agriculture, and industry. These materials are highly reactive in the environment and interact with elements available in soil and water, affecting their bioavailability for plants and microorganisms. The small size of metal-based nanomaterials results in a high rate of their uptake by living organisms including plants. The impact of nanomaterials on living organisms and their toxicity level depends on various factors including their size, concentration, and type, as well as the exposed organism. Studies on the fate of nanomaterials in the environment have reported the potential of plants to accumulate nanomaterials. However, the exact mechanism of nanomaterials uptake and their fate in plants is not well understood. Nanomaterials accumulated in plants can enter the human body through direct consumption of plants or through the food chain. Therefore, it is important to understand how they interact with plants to further protect public health and improve sustainable agricultural practices. This research project investigates the fate of the commonly used metal-based nanomaterial, silver nanoparticles, in plants and their interaction with essential plant nutrients such as potassium, magnesium, and zinc. This will involve a series of molecular, physiological, and analytical studies to understand the form and the site of accumulation of silver nanoparticles in plants, in addition to their impact on membrane transporters. The PI will mentor undergraduate and master’s students during the study and provide educational and research opportunities for underrepresented minorities in STEM fields including women, first-generation college students, and people of color. To improve public awareness about nanomaterials and their fate in plants, a three-dimensional model will be created based on the results of this study and will be displayed in a local science museum. Nanomaterials are used worldwide in various sectors including medicine, agriculture, and industry. Silver nanoparticles are a common form of metal-based nanomaterials. These materials can be oxidized in the environment and be transformed into the ionic form, which is more interactive and toxic than the particulate form. Silver nanoparticles, in either particulate or ionic form, impact plant physiology and metabolism at various levels including the membrane transporters and electrical potential, which subsequently affects plant water absorption and nutrient translocation. Silver nanoparticles are not needed for plant growth and there is not a membrane transporter specifically designated for silver nanoparticles to enter cells. However, since plants can translocate and accumulate these nanoparticles in their tissues, there must be a transporter that allows these materials to pass across the membrane. Plasma membrane aquaporin and potassium channels are among the possible transporters for silver nanoparticles. Once these nanoparticles are taken up by plants, their presence in inter- and intra- cellular spaces changes the electrochemical potential of cells. To provide equilibrium, the expression of several membrane transporters including proton ATPase, and cation and anion channels can be impacted. This in turn affects the movement of essential nutrients and water across the membrane, turgor pressure, and cytosolic and apoplastic pH level. These series of events can impact the structure of xylem cells and subsequently bioaccumulation and translocation of essential nutrients and water in plants. Due to the role of aquaporins in the translocation of water, maintaining turgor pressure, and potentially transporting silver nanoparticles across the membrane, in this study tomato (Lycopersicon esculentum) and mutant for aquaporin PIP1 will be exposed to silver nanoparticles in order to determine the mechanism of translocation of these nanoparticles in plants and their interaction with plant essential nutrients. This project will include a series of analytical, molecular, and morphological analyses to achieve these aims, including the concentration, form, and site of silver nanoparticles accumulation in plants, the effects of their exposure on membrane transporters, and the impact of their exposure on vascular tissues. Results will provide information in understanding the fate of nanomaterials in plants and to efficiently use plants for phytoremediation approaches.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.