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

这项研究项目探索了纳米氧化铜在植物-根界面上的活性。氧化铜是一种在杀菌剂和化肥应用中广泛使用的纳米颗粒(直径小于100 nm)；然而，在非常窄的浓度范围内，植物对这种材料的反应范围从毒性到植物健康。根部与有益微生物的结合，无论是作为内部的或内生的，还是作为外部或附生的定殖者，都将影响该区域的纳米颗粒的生物活性。在这项研究中采用了一种系统的方法来识别和阐明纳米颗粒-微生物-植物-土壤成分相互作用的关键方面，以更好地预测这种广泛使用的纳米颗粒对环境和健康的影响。详细说明纳米粒子在植物根部区域的相互作用和影响，这些细菌通常与田间种植的植物有关，这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、管理和使用工程纳米粒子的指导方针。虽然这一研究项目侧重于植物系统，但它涉及有益微生物在许多生物体的健康和生存中发挥的重要作用，因此，这项研究和相关的推广将扩大不断增长的微生物组研究网络。这项研究项目的主要目标是确定三个主要因素的组合作用，即植物、定植微生物和土壤成分，它们相互作用，以调节根际中纳米颗粒的生物活性，根际是存在于植物根周围的对植物健康至关重要的区域。正在采用两个模拟管理这种相互作用的关键要素的模型系统。第一个系统使用硅砂的固体生长基质，用具有特征的土壤孔隙水进行修正，以复制复杂的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来自田间种植的小麦的微生物分离：从种子中分离的内生芽孢杆菌和假单胞菌根表面定殖者。这些微生物是许多诱导植物对非生物和生物胁迫(如干旱和病原体)耐受的典型菌株。第二个系统是一种模拟根的中空纤维膜，正在研究微生物在其上的定植、代谢产物的产生和生物膜的形成。通过纤维管腔输送。与块状氧化铜和铜盐的反应相比，由表征的根代谢物构建的根际溶液可以识别影响生物膜形成、细菌对纳米颗粒暴露的适应能力和代谢物产生的根代谢物和土壤成分。这个将工程学与化学和生物科学相结合的跨学科项目，正在通过调查人员实施的美国原住民暑期导师计划(NASMP)支持来自犹他州州立大学地区校园的研究生、本科生和高中生，以及代表不足的学生？实验室。STEM面向普通公众和K-12学生的活动涉及与ARTsySTEM倡议的合作，该倡议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.