Researchers at the University of Kansas have found that soil microbes in Kansas carry 'memories' of past droughts, influencing plant growth and resilience. Native plants respond more strongly to these microbial legacies than crops like corn, suggesting co-evolutionary adaptations. The discovery, published in Nature Microbiology, highlights potential applications for agriculture amid climate change.
A study published in Nature Microbiology examined soils from six locations across Kansas, ranging from the wetter eastern regions to the drier High Plains in the west, influenced by the Rocky Mountains' rain shadow. The research tested 'legacy effects,' where microbes adapted to local climates over years shape soil properties and plant performance.
"The bacteria and fungi and other organisms living in the soil can actually end up having important effects on things that matter, like carbon sequestration, nutrient movement and what we're particularly interested in -- the legacy effects on plants," said co-author Maggie Wagner, associate professor of ecology and evolutionary biology at the University of Kansas.
The team, in collaboration with the University of Nottingham in England, conducted experiments at the University of Kansas. They exposed microbial communities from these soils to either ample water or limited water for five months, creating contrasting moisture histories. Even after thousands of bacterial generations, drought memory remained detectable.
Native plants, such as gamagrass, showed stronger responses to these legacies compared to corn, a crop domesticated in Central America and introduced to the area only a few thousand years ago. "We think it has something to do with the co-evolutionary history of those plants, meaning that over very long periods, gamagrass has been living with these exact microbial communities, but corn has not," Wagner explained.
Genetic analysis revealed heightened activity of the nicotianamine synthase gene in plants under drought conditions, but only when paired with drought-experienced microbes. This gene aids iron acquisition from soil and influences drought tolerance. The findings suggest gamagrass genes could enhance corn resilience, informing biotech efforts in the multibillion-dollar microbial agriculture industry.
Lead author Nichole Ginnan, now at the University of California-Riverside, and other collaborators including Natalie Ford, now at Pennsylvania State University, contributed to this interdisciplinary work funded by the National Science Foundation's Division of Integrative Organismal Systems.