THOR wrangles complex microbiomes into a model for improving them

MADISON - "Microbial communities run the world," says Jo Handelsman, director of the Wisconsin Institute for Discovery at the University of Wisconsin-Madison.

"People always laugh when I say that," she adds. "But it's true."

Our rich new understanding of microbial communities and their influence on human health or crop productivity has led to the dream of changing these communities to produce benefits. In pursuit of that dream, millions of Americans now take probiotics, beneficial microbes they hope will improve their gut. 

But the immense complexity and resiliency of these microbiomes leave researchers unsure how to produce predictable and long-lasting changes for the better. 

New research by Handelsman and her collaborators addresses that complexity head-on. The team developed a community they named THOR, three species of bacteria isolated from soybean roots and grown together. The complex community of microbes developed new behaviors together that couldn't be predicted from the individual members alone — they grew tougher structures known as biofilms, changed how they moved across their environment, and controlled the release of a novel antibiotic.

Each of the three members of THOR has a sequenced genome, and an array of tools are available to easily study the bacteria in isolation and together, which opens up opportunities to start unraveling the complexity of microbial communities like THOR and others. A better understanding of these microbiomes could help scientists figure out how to improve them.

The work is published March 5 in the journal mBio. The work was led by Handelsman lab postdoctoral researcher Gabriel Lozano with collaborators at the UW-Madison Department of Plant Pathology, Yale University and other institutions.