CuO NP bioactivity in the wheat rhizosphere: Interplay of soil chemistry, root exudation, and biofilms

本研究项目探讨氧化铜纳米粒子在植物-根界面的活性。氧化铜是一种广泛应用于杀菌剂和肥料的纳米颗粒（直径小于100纳米的颗粒）；然而，植物对这种物质的反应范围从毒性到植物健康，在一个非常狭窄的浓度范围内。根与有益微生物的关联，无论是内部的，或内生的，还是外部的，或附生的，定殖，将影响纳米颗粒在该区域的生物活性。本研究采用系统方法来识别和阐明纳米颗粒-微生物-植物-土壤组分相互作用的关键方面，以更好地预测这类广泛使用的纳米颗粒对环境和健康的影响。详细描述纳米颗粒在植物根区与通常与田间种植植物相关的特定细菌定殖的相互作用和影响，将提高对植物微生物组重要作用的理解，并有助于安全处理、管理和利用工程纳米颗粒的指导方针。虽然聚焦于植物系统，但该研究项目涉及有益微生物在许多生物的健康和生存中发挥的重要作用，因此研究和相关的推广将扩大微生物组研究网络。本研究项目的主要目的是确定三个主要因素的综合作用：植物、定植微生物和土壤成分，它们相互作用来调节根际中纳米颗粒的生物活性，根际是植物根周围对植物健康至关重要的区域。目前正在采用两个模拟控制这种相互作用的关键元素的模型系统。第一个系统使用硅砂的固体生长基质，外加特征土壤孔隙水，以复制复杂土壤溶液环境的关键特征，包括无机和有机成分。在这个系统中生长的小麦将被从田间种植的小麦中分离出来的微生物定植：从种子中分离出来的内生芽孢杆菌和根表面定植的假单胞菌。这些微生物是诱导植物耐受非生物和生物胁迫（如干旱和病原体）的许多分离物的典型。第二个系统是一个模拟根的中空纤维膜，微生物的定植、代谢物的产生和生物膜的形成正在研究中，以响应定义的根溶液。通过纤维腔输送。由表征的根代谢物构建的根溶液可以识别影响生物膜形成的根代谢物和土壤成分，细菌对纳米颗粒暴露的恢复能力，以及对氧化铜纳米颗粒的反应产生的代谢物，与散装氧化铜和铜盐的反应形成对比。这个跨学科的项目，将工程与化学和生物科学相结合，通过美国原住民夏季指导计划（NASMP），支持来自犹他州立大学地区校区的研究生、本科生、高中生和代表性不足的学生。实验室。STEM向公众和K-12学生的推广涉及与ARTsySTEM倡议的合作，旨在更好地将艺术与科学联系起来。

This research project explores copper oxide nanoparticle activity at the plant-root interface. Copper oxide is a widely-used nanoparticle (a particle with a diameter below 100 nm) in fungicidal and fertilizer applications; however, plant responses to this material span from toxicity to plant health over a very narrow concentration range. The association of roots with beneficial microbes, both as internal, or endophytic, and external, or epiphytic, colonizers, will influence nanoparticle bioactivity in this zone. A systems approach is employed in this research to identify and elucidate key aspects of nanoparticle-microbe-plant-soil component interactions to better predict the environmental and health implications of this broadly used class of nanoparticles. Detailing the interaction and impact of nanoparticles in the plant root zone colonized with defined bacteria commonly associated with field-grown plants will improve the understanding of the important role of the plant microbiome as well as contribute to guidelines for the safe handling, management, and utilization of engineered nanoparticles. While focusing on a plant system, this research project relates to the essential roles that beneficial microbes play in the health and survival of many organisms, thus the research and associated outreach will augment the growing network of microbiome studies. The main objective of this research project is to identify the combined roles of three major factors, the plant, colonizing microbes, and soil components, that interplay to condition the bioactivity of nanoparticles in the rhizosphere, the zone vital to plant health that exists around a plant root. Two model systems that mimic key elements governing this interplay are being employed. The first system uses a solid growth matrix of silica sand amended with characterized soil pore-waters in order to replicate a key feature of the complex soil solution environment, including inorganic and organic components. Wheat grown in this system will be colonized by microbial isolates from field-grown wheat: A bacillus endophyte isolated from seeds, and a pseudomonad root surface colonizer. These microbes are typical of many isolates that induce plant tolerance to abiotic and biotic stress, such as drought and pathogens. The second system is a root-mimetic, hollow fiber membrane on which microbe colonization, metabolite production, and biofilm formation are being investigated in response to defined ?rhizosolutions? delivered through the fiber lumen. Rhizosolutions constructed from characterized root metabolites permit identification of root metabolites and soil components influencing biofilm formation, bacterial resilience to nanoparticle exposure, and metabolite production in response to the copper oxide nanoparticles, contrasted with responses from bulk copper oxide as well as copper salts. This interdisciplinary project, which merges engineering with chemical and biological sciences, is supporting graduate, undergraduate, and high school students, and underrepresented students from the Utah State University regional campuses through the Native American Summer Mentorship Program (NASMP) in place in the investigators? laboratories. STEM outreach to the general public and K-12 students is involving collaboration with an ARTsySTEM initiative, designed to better link art with science.