Inhibitory and nutrient use phenotypes among coexisting Fusarium and Streptomyces populations suggest local coevolutionary interactions in soil

Authors: ESSARIOUI, ADIL - National Institute Of Agronomic Research Of Morocco (INRA); LEBLANC, NICHOLAS - University Of Minnesota; LINDSEY, OTTO-HANSON - University Of Minnesota; Schlatter, Daniel; Kistler, Harold; KINKEL, LINDA - University Of Minnesota

Submitted to: Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/14/2019
Publication Date: 3/1/2020
Citation: Essarioui, A., LeBlanc, N.R., Otto-Hanson, L., Schlatter, D.C., Kistler, H.C., Kinkel, L.L. 2020. Inhibitory and nutrient use phenotypes among coexisting Fusarium and Streptomyces populations suggest local coevolutionary interactions in soil. Environmental Microbiology. 22(3):976-985. https://doi.org/10.1111/1462-2920.14782.
DOI: https://doi.org/10.1111/1462-2920.14782

Interpretive Summary: Despite the persistent presence of diverse plant pathogens, America’s native prairies are healthy, thriving communities of perennial herbaceous plants. How do these communities avoid significant disease epidemics? Important lessons likely can be learned from these communities that can be applied to agriculture to create healthier, more productive plants. This study evaluates a genus of soil bacterium found in native prairie systems, Streptomyces, vital in the fight against plant pathogens. These bacteria, which are found naturally within the soil, are effective in suppressing plant pathogens since they produce antibiotic compounds when competing for food in highly competitive soils. The study centers on the interaction of these bacteria with plant pathogenic Fusarium fungi. How Streptomyces within the complex microbial community may compete with Fusarium fungi within the same soil community is elucidated. This information may be used by agronomists to improve plant productivity by providing a robust foundation for understanding the impacts of agronomic practices on soil communities, and in doing so may help harness the benefits of the indigenous microbial community to make agricultural crops more productive.

Technical Abstract: Although bacteria and fungi are key components of virtually all microbial habitats, the significance of fungal-bacterial interactions for the dynamics of specific bacterial and fungal populations and their ecology and evolutionary biology has been overlooked. Specifically, despite the broad consensus that antibiotic interactions play a major role in providing a survival advantage for microbes under competitive conditions, the significance of antibiotic production in mediating cross-kingdom coevolutionary interactions remains poorly explored. Here, we searched for evidence for local adaptation between populations of the fungus Fusarium and the bacterium Streptomyces in soil. Specifically, we characterized reciprocal inhibitory among Streptomyces and Fusarium populations, and explored antimicrobial inhibition in relation to niche overlap among populations. We found evidence for local adaptation between Fusarium and Streptomyces populations as evidenced by the presence of significantly greater inhibition among sympatric than allopatric populations from prairie soil. Additionally, for both taxa, there was a significant positive correlation between the strength of inhibition against the other taxon and the intensity of resource competition from that taxon among sympatric but not allopatric populations. These data suggest that coevolutionary antagonistic interactions between Fusarium and Streptomyces are driven by resource competition and support the hypothesis that antibiotics act as weapons in mediating bacterial-fungal interactions in soil.