When looking for methods of improving crop tolerance to drought, saline soils, certain pathogens and other agricultural concerns, attention is mostly focused on such possible solutions as closely related but better performing species of plant, directly attacking the cause of the stress or searching out transgenic solutions.
But the symbiotic relationship between the plant and its microbiome may hold some secrets that could help us adapt some of the most significant issues in agriculture. If certain microbiomes assist a host plant to survive or even prosper with such stressors as reduced water availability or increased salt concentration when compared to other microbiomes, we can potentially inoculate soils with the right species of microorganisms to maintain or increase our food production productivity.
A review paper in the journal Trends in Microbiology looked at a number of experimental methods in selecting for beneficial microbiomes by assessing the effect of different soils on a particular host trait. The paper describes a number of methods that have been used, the advantages and disadvantages of each, as well as experiment design considerations that have been taken from previous research in the area.
One method that appeared to garner the most favour by the writers was growing a subject plant species in a variety of soils, then selecting lines that met a particular criteria eg number of flowers. The microbiome of selected lines are then inoculated into sterilised soil and re-sown with a genetically identical host plant species. This method results in a representative sample of all microorganisms in the selected line being retained and allow the host plant to continue selecting for the most beneficial (or excluding the non-beneficial) microorganism.
As gene sequencing technology continues to improve, the possibility of identifying the different species and ratios of species in the most beneficial microbiomes is continuing to grow, in turn improving precision in food production practices.