Using Biologicals to Remodel a Plant’s Microbiome

- Molly Cadle-Davidson

Most ABM’s biologicals are formulated as seed treatments that contain a few strains of Trichoderma that we know work symbiotically with the plant to improve plant performance. Several mechanisms enable these changes in plant performance including induced changes in the host plant’s gene expression and a remodeling of the rhizosphere microbiome (phytobiome) or root-associated microbial community. Remarkably, this remodeling results in changes in how this microbial community functions, all due to the introduction of the endophytic seed treatment.

The plant reacts to everything in the soil, including the microbes already present. The plant, the microbes, the available nutrients and a multitude of other factors all make up the local environment. The ability to survive in this environment is called fitness, and is exactly what the evolutionary tenant “survival of the fittest” refers to. Microbes work together as communities to survive and plants growing in the soil must be capable of also working with these microbes to thrive. The introduction of our biological seed treatments has the effect of remodeling that community to enable the best resource utilization and the best survival within that environment is the goal. Like the conductor of an orchestra.

To take this analogy further, a good conductor will be able to lead any orchestra and produce beautiful music. Introducing a small number of robust strains as seed treatments can aid in reduction of agricultural variability because, even across environments, those strains can promote the good actors and suppress the bad actors for the very selfish goal of forming a better niche or environment in which to grow and acquire nutrients.

An alternate approach also being tested is the introduction of reconstituted microbiomes, ostensibly containing all microbial members required for a productive plant. This strategy will rely on all of these microbes being robust in all environments and does not necessarily provide a functional “conductor” for the microbial “orchestra.”

We need the microbes to be smarter than we are. At this time, no one knows the details of the whole picture. What these biologicals do when they get in the soil is what they need to do to survive.