Plant-Associated Bacterial Isolate Collections from Grasses Show Plant Beneficial Functions

Executive Summary:

Two collections of bacterial isolates, one from the epicuticular wax and root mucilage of sorghum and one from the rhizosphere of switchgrass, were enriched for plant beneficial functions. The inoculation of a subpopulation of the switchgrass isolates resulted in increased biomass production in switchgrass compared to the control.


Plant-associated microbial communities can function to support plant growth and increase plant resistance to environmental stresses. Isolating and characterizing native microbial communities from crop plants is useful for identifying field-relevant isolates that can be utilized to support plant growth and function. These isolates can then be characterized through genetic, taxonomic, and phenotypic analyses to understand their plant beneficial functions. These isolates can be added to seeds or soil to increase plant growth and yield.

Description of Technology:

Bacterial isolates were collected from the epicuticular wax and root mucilage of sorghum (Sorghum bicolor) grown in Michigan and Texas and from the rhizosphere of switchgrass (Panicum virgatum) grown in Michigan. These isolate collections were enriched for putative plant-beneficial traits by using media-based enrichment processes. For the sorghum isolates, the media selected for nitrogen fixation, phosphate solubilization, resistance to terpenoids, use of methanol as a carbon source, and tolerance to desiccation. For the switchgrass isolates, the media selected for positive responses to host factors, specifically switchgrass metabolites. Isolates were further characterized through genetic, genomic, and taxonomic analyses, using 16S rRNA gene sequencing.

A compatible subpopulation of the switchgrass isolates was tested in two greenhouse experiments for the potential plant beneficial effects. In one experiment, soil was inoculated with the isolate community, then the soil was used to grow switchgrass. In the second experiment, switchgrass seeds were soaked in the isolate community then planted. In both experiments, plants grown with the isolate community had increased dry shoot biomass and dry root biomass compared to mock inoculated control plants.

Key Benefits:

Application of compatible isolates to seeds or soil showed increase in aboveground and belowground plant growth


Application to soil or seed of grass crops (e.g., maize, wheat, small grains) to increase growth and yield as microbial biostimulant

Related publications:

Mechan-Llontop et al. (2023). Phyllosphere exudates select for distinct microbiome members in sorghum epicuticular wax and aerial root mucilage. Phytobiomes J. 7(2) 184-197.

Mechan-Llontop et al. (2023). Genome-sequenced bacterial collection from sorghum aerial root mucilage. Microbiol. Resour. Announc. 12(12) e00468-23.

Mechan-Llontop et al. (2023). Genome-sequenced bacterial collection from sorghum epicuticular wax. Microbiol. Resour. Announc. 12(12) e00484-23.

Protection Status:



            Ashley Shade, Marco Mechan-Llontop, Lille Cunic, Xingxing Li, Keara Grady, Robert Last

MSU Technology Number(s):





Patent Information:


For Information, Contact:

Julia Miller
AgBio Technology Manager
Michigan State University