Plants produce all kinds of chemical signals in response to their environment. These signals, both airborne and through the soil ecosystem, can be picked up by like plants or even eavesdropped on by other plants, especially when the plant is under attack by insects or diseases. While the majority of communication takes place in the soil, we all know the smell of fresh cut grass releasing clouds of volatile chemicals. This communication is a survival mechanism, providing nearby plants a heads-up to beef up their anti-insect resistance or produce disease-fighting enzymes.
Researchers from the Swedish University of Agricultural Sciences have found that plants secrete chemicals into the soil and other plants nearby use their roots to detect and “understand” the signals associated with particular chemical traces. The discovery is not only fascinating, but it raises additional questions, like what plants might be saying to one another with these chemical signals.
US Cooperative Extension specialist Peggy Lemaux discovered that sorghum plants cope with drought conditions by the plants’ roots and adjoining microbial communities communicating in a chemical language that appears to improve the plants’ chances of surviving water stress. The role of drought in restructuring the root microbiome was the first published discovery to come out of a drought research project underway since 2015 in the fields at UC Kearney Research and Extension Center in Parlier.
“When a sorghum plant is subjected to drought, it starts sloughing off metabolites, nutrients and amino acids from the roots. The compounds appear to communicate to the neighboring microbial community that the plant is under stress,” Lemaux said. “That selects out a certain population of microbes. Certain types of microbes increase; others go away. When you add water back, the microbial community returns to its pre-drought population in just a few days.”
“The [selected] microbes appear to improve plant growth during drought,” Lemaux said. “Those microbes appear to be helping plants survive drought. We didn’t know that was happening before we got these results.”
We’ve known for awhile that plants use fungi in the soil as the Earth’s internet for communication. The 19th-century German biologist Albert Bernard Frank coined the word “mycorrhiza” to describe these partnerships, in which the fungus colonizes the roots of the plant. Fungal networks boost their host plants’ immune systems by triggering the production of defense-related chemicals. They also provide plants with extended access to nutrients and water.
With all this communication going on validating the vital roles of the microbial community, wouldn’t it make sense to make every effort to have robust, microbially active soils given these confirmed benefits? The majority of Andaman Ag products are microbial-based, giving way to exceptional plant health and, we’re now learning, contributing to the communication pipeline among plants to improve their defensive abilities!