CAREER: Protecting Microbes to Protect Plants

Non-technical description

Chemicals 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 abstract

Many 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.