A new study is underscoring the importance of studying microbes in their natural setting, rather than relying solely on laboratory research.
Researchers found that a set of corn root bacteria behaved completely differently when grown on the plant rather than in a lab, with thousands of proteins changing when placed in their natural habitat.
For the study, published in mSystems, researchers grew seven species of corn root bacteria under two conditions—once in a lab setting, using a nutrient solution, and once directly on the roots of corn plants—then measured which proteins each species produced under each condition.
All seven species showed major behavioral shifts, though the specifics varied widely from one to the next. Some bacteria became more mobile once they reached the plant root, activating functions associated with movement and swimming, while others did the opposite, attaching to the root and becoming far more stationary.
Microbes on the plant also displayed a range of other behaviors, including activating secretion systems, solubilizing phosphate, and consuming different sugars than they did in the lab. Between 20 and 60 percent of each species' proteins turned out to be produced differently depending on the setting.
The scale of the shift surprised the research team, who had expected some variation between lab and field conditions but not a wholesale change in behavior across every species tested.
“Comparing the microbe growing on the plant to outside of the plant, the most mind-blowing thing was that these microbes completely changed their programming,” said principal investigator Manuel Kleiner, associate professor of plant and microbial biology at North Carolina State University. “It's not just 10 or so genes, it's thousands that completely shift as soon as they start interacting with the plant.”
The findings challenge how much scientists can rely on lab-based studies alone to understand how microbes function in the real world.
The team sats future research should examine how multiple microbes interact and cooperate to colonize plants together, work that will be important for developing practical products for sustainable agriculture.
Data from North Carolina State University