Indiana University researchers are studying how microbes can make plants withstand drought in order to help farmers make the right management decisions.
“Microbes play a big role in the lives of plants and animals, both in positive and negative ways,” explained Lana Bolin, a Ph.D. candidate at the IU Department of Biology. “On one hand, microbes can be pathogenic and harm other organisms. On the other hand, microbes can be tremendously beneficial to other organisms. Plants commonly benefit from bacteria and fungi that help them acquire nutrients and fend off pathogens.”
Researchers collected soil from 70 farms in Indiana, Illinois and Michigan and brought them to a greenhouse at IU. They then inoculated corn plants that were grown under either drought-stressed or well-watered conditions with the soil.
“At the end of the experiment, we'll weigh and count the corn kernels produced to see how our microbe and watering treatments affected corn yield,” Bolin told Indiana Environmental Reporter.
The project, a collaboration between ecologists and sociologists, also involved in-depth interviews with the farmers to understand how they manage their fields, including decisions involving irrigation, cover crops and tilling methods.
The researchers said they could link farm management practices and drought tolerance. In some instances, microbes developed with those practices
“Drought doesn't reduce plant growth as much if the plants are grown with microbes from dry environments, compared to when they're grown with microbes from wet environments. And we don't have a super clear idea of why this is,” Bolin said. “One possibility is that the traits that microbes express that help them survive under drought just happen to also benefit plants.”
The researchers saw that drought reduced plant height between 15% and 47%, depending on which farm its microbes came from.
Some bacteria create a sticky substance called a biofilm that helps them survive drought stress, and these biofilms might coat plant roots and prevent water loss from the roots during drought.
“Another possibility is that plants can tell which microbes are most beneficial, and they might increase the fitness of these beneficial microbes in some way. But this is an open question, and one that we're hoping to address with our research.”
Researchers are still collecting data from this experiment, but substantial variation among farms in the resilience they confer to plants in growth terms has been seen.