New Research Program Aims to Understand Key Metabolites That Encourage Plant-Bacterial Nutrient Exchanges

Sustainable agricultural practices are necessary to mitigate climate change and produce more food, fiber, and renewable fuels. A promising new frontier in agriculture is to promote beneficial interactions with microbes as a sustainable mechanism of providing nutrients to crops. 'Microbial' products are already available to farmers; however, in practice, these products display highly variable results and current data suggest that this is tightly linked to the ability of the beneficial microbes to colonize and persist with their plant hosts.

Many recent studies implicate plant root exudates as a major factor that determines the colonization and persistence (C&P) phenotypes of exogenously supplied microbes. However, current scientific knowledge of how plant exudates affect colonization and persistence is too limited to be translated into improved performance of microbial products.

A new research program led by Rebecca Bart, PhD, member, Donald Danforth Plant Science Center and Doug Allen PhD, member and USDA research scientist will build on previous foundational research within the Danforth Center's Subterranean Influences on Nitrogen and Carbon (SINC) Center to better understand the key metabolites that encourage plant-bacterial nutrient exchanges. Previous work has confirmed that under resource limited conditions, plants cultivate interactions with microbial collaborators - exchanging carbon for nutrients. These interactions can increase plant health, but do not fully compensate for a lack of exogenously applied nutrients.

Bart, Allen and their collaborators received a grant from the National Institute of Food and Agriculture, Agricultural Microbiomes in Plant Systems and Natural Resources program to support laboratory, field and computational research methods. Together, these approaches will yield new synthetic communities of bacteria with plant growth promoting abilities and greater knowledge of how plant root exudates affect the colonization and persistence of the synthetic communities.

"To harness the power of microbial interactions in modern day agriculture, we must develop methods of cultivating beneficial interactions, without starving our crop plants of nutrients and causing yield reductions," said Bart. "By developing and deploying new methods of forming robust, stable and productive synthetic communities that can be used as inoculants, we will generate foundational knowledge on the key metabolites that encourage plant-bacterial nutrient exchanges."

This research will yield new strategies to develop microbial products that show robust performance in the field. The key to success will be discovering the fundamental rules that govern C&P of beneficial microbes with their plant hosts. The long-term outcome of this research will be to optimally redesign production agriculture through the lens of the 'community of players' that can ensure a sustainable planet.

If we are able to develop strategies to increase the C&P of microbial based products, these discoveries will help farmers achieve high yields with less external inputs while also protecting their soil health and the environment."

Rebecca Bart, PhD, member, Donald Danforth Plant Science Center