CAREER: Protecting Microbes to Protect Plants

农业中使用的化学品，如化肥和杀虫剂，使我们能够生产足够的粮食来养活快速增长的全球人口。此外，农业一般占美国温室气体排放量的11%。微生物自然地发挥着这些化学品在农业、土壤改良、保护植物免受害虫侵害和支持植物恢复力中的所有作用。但是，当一种有益的菌株被从其原生环境中移除以供研究或开发作为化学品的替代品时，微生物往往是脆弱的，当暴露于热、紫外线和湿度等应激源时就会死亡。这些限制阻碍了它们作为肥料和杀虫剂的替代品的广泛使用。自组装涂层是从常见的矿物质和植物提取物中开发出来的，可以保护微生物免受压力。然而，至关重要的是，它们保护微生物的原因尚不清楚。该项目的目标是了解这些材料如何保护微生物以及它们对常见环境压力的保护程度。与研究工作相结合，将开发教育计划，以培训退伍军人在生物技术的职业生涯，使他们的发展成为技术工人在这个不断增长的领域。技术摘要许多有益的微生物菌株对环境压力如热和湿度敏感，由于加工，运输和储存的限制，防止其有效生产。目前的微生物保护策略依赖于对添加剂或澄清剂的专门测试，并根据具体情况进行优化。PI的实验室已经开发出自组装的纳米级金属酚醛网络（MPN），作为物理“盾牌”来保护微生物免受压力，但它们的保护机制和对其他微生物的可推广性仍然是一个谜。迄今为止，MPN微生物保护已经与常规保护剂类似地接近，其中每种微生物菌株通过不同的MPN组合物得到最好的保护。18种金属离子通过与一系列多酚配位形成MPN，为系统评价提供了很大的化学空间。在这个项目中，目标是：根据MPN的组成确定其物理特性的趋势，并将物理趋势与微生物的氧化应激反应联系起来。还将在其他类别的农业相关微生物上评估MPN保护，以确定最佳MPN组合物是否与特定微生物的最具破坏性的应激源相关。该项目通过评估MPN对其他农业相关微生物的功效，并确定MPN物理特性如何影响受保护微生物的行为，来解决这一知识空白。这些系统地表征MPN及其保护的努力将使微生物作为农用化学品的可持续替代品的快速实施成为可能，并支持未来对新微生物的先验涂层选择。从拟议的工作中获得的集体知识将引起研究人员的兴趣，从研究非生物-生物界面或开发具有可控物理特性的生物相容性材料的材料科学家到确定压力源对细胞影响的微生物学家。这些研究代表了对MPN微生物保护机制的首次调查，扩大了我们对这些材料的物理和生物保护特性的基本理解，并支持新防护材料的合理设计和工程。这项工作的跨学科性质非常适合生物技术劳动力培训。该项目涉及为代表性不足的群体的退伍军人提高STEM和创业知识，这些群体的失业率一直高于一般退伍军人。一个关于生物技术创业的研讨会将被开发，以提供这些退伍军人接触到STEM和创业资源的职业生涯。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Non-technical descriptionChemicals used in farming like fertilizers and pesticides have allowed us to produce enough food to feed the rapidly-growing global population. Additionally, agriculture in general is responsible for 11% of US greenhouse gas emissions. Microbes naturally serve all of the roles of these chemicals used in farming, fertilizing soil, protecting plants from pests, and supporting plant resilience. But when a beneficial strain is removed from its native environment for study or development as an alternative to chemicals, the microbes are often delicate and die when exposed to stressors like heat, UV light, and humidity. These limitations prevent their broad use as replacement for fertilizers and pesticides. Self-assembled coatings have been developed from common minerals and plant extracts that protect microbes from stressors. Critically, though, the reason why they protect microbes is not understood. The goal of this project is to understand how these materials protect microbes and the extent of their protection against common environmental stressors. Integrated with the research effort, educational programs will be developed to train veterans for careers in biotechnology to enable their development as skilled workers in this growing field.Technical abstractMany beneficial strains of microbes are sensitive to environmental stressors such as heat and humidity, preventing their effective production due to processing, transport, and storage limitations. Current strategies of microbial protection rely on ad hoc testing of additives or encapsulants, with optimization on a case-by-case basis. The PI’s lab has developed self-assembling, nanoscale metal-phenolic networks (MPNs) to serve as physical “shields” to protect microbes from stress, but their mechanism of protection and generalizability to additional microbes remain a mystery. MPN microbial protection has been approached similarly to conventional protectants to-date, with each microbial strain best protected by a different MPN composition. Eighteen metal ions have been used to form MPNs through coordination to a range of polyphenols, providing a large chemical space for systematic evaluation. In this project, the goals are to: identify trends in the physical properties of MPNs based on their composition and connect the physical trends to oxidative stress responses in microbes. MPN protection will also be evaluated on additional classes of agriculturally-relevant microbes to determine if optimal MPN composition correlates to the most damaging stressor to a particular microbe. This project addresses this gap in knowledge by evaluating the efficacy of MPNs on additional classes of agriculturally-relevant microbes and determining how MPN physical properties impact the behavior of protected microbes. These efforts to systematically characterize MPNs and their protection will enable the rapid implementation of microbes as sustainable alternatives to agrochemicals and support a priori coating selection for new microbes in the future. The collective knowledge gained from the proposed work will be of interest to researchers ranging from materials scientists studying abiotic-biotic interfaces or developing biocompatible materials with controllable physical properties to microbiologists determining the impact of stressors on cells. These studies represent the first investigations into the mechanism of MPN microbial protection, expanding our fundamental understanding of the physical and bioprotective properties of these materials and supporting the rational design and engineering of new protective materials. The interdisciplinary nature of this work is well-suited for biotechnology workforce training. The project involves advancing STEM and entrepreneurship literacy for veteran members of underrepresented groups, a population with consistently higher unemployment rates that the general veteran population. A workshop on Biotech Entrepreneurship will be developed to provide these veterans exposure to careers in STEM and entrepreneurship resources.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.