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ARS Home » Midwest Area » St. Paul, Minnesota » Cereal Disease Lab » Research » Publications at this Location » Publication #330228


Location: Cereal Disease Lab

Title: Plant community richness mediates inhibitory interactions and resource competition between Streptomyces and Fusarium populations in the rhizosphere

item ESSARIOUI, ADIL - University Of Minnesota
item LEBLANC, NICHOLAS - University Of Minnesota
item Kistler, H - Corby
item KINKEL, LINDA - University Of Minnesota

Submitted to: Microbial Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2016
Publication Date: 1/5/2017
Citation: Essarioui, A., LeBlanc, N., Kistler, H.C., Kinkel, L.L. 2017. Plant community richness mediates inhibitory interactions and resource competition between Streptomyces and Fusarium populations in the rhizosphere. Microbial Ecology. 74:157-167.

Interpretive Summary: Each year, plant diseases caused by the fungus Fusarium reduce the value of a wide range of cultivated crops world-wide. Effective control measures for the diseases caused by these fungi usually are not readily available. We seek to develop new principles and measures for disease management by learning more about the role of these fungi as part of microbial communities associated with a host plant. Fusarium fungi have evolved novel methods by which they may adapt to particular plant hosts and the microbes, both fungi and bacteria, that are part of the normal plant flora. Further knowledge of the genetic basis for how Fusarium interact with other microbes may be used to develop alternative approaches to loss management and control. This information will be helpful to plant improvement specialists who are working to develop plants resistant to these pathogens or for developing novel strategies for disease control. These observations likely will influence thinking and planning of cropping systems arising from agricultural monoculture and intercropping and their impact on fungal soil communities and plant health. The primary users of the research in this publication will be other scientists engaged in research to improve disease management on small grain crops.

Technical Abstract: Plant community characteristics impact rhizosphere Streptomyces nutrient competition and antagonistic capacities. However, the effects of Streptomyces on, and their responses to, coexisting microorganisms as a function of plant host or plant species richness have received little attention. In this work, we characterized antagonistic activities and nutrient use among Streptomyces and Fusarium from the rhizosphere of Andropogon gerardii (Ag) and Lespedeza capitata (Lc) plants growing in communities of 1 (monoculture) or 16 (polyculture) plant species. Streptomyces from monoculture were more antagonistic against Fusarium than those from polyculture. In contrast, Fusarium isolates from polyculture had greater inhibitory capacities against Streptomyces than isolates from monoculture. Although Fusarium isolates had on average greater niche widths, the collection of Streptomyces isolates in total used a greater diversity of nutrients for growth. Plant richness, but not plant host, influenced the potential for resource competition between the two taxa. Fusarium isolates had greater niche overlap with Streptomyces in monoculture than polyculture, suggesting greater potential for Fusarium to competitively challenge Streptomyces in monoculture plant communities. In contrast, Streptomyces had greater niche overlap with Fusarium in polyculture than monoculture, suggesting that Fusarium experiences greater resource competition with Streptomyces in polyculture than monoculture. These patterns of competitive and inhibitory phenotypes among Streptomyces and Fusarium populations are consistent with selection for Fusarium-antagonistic Streptomyces populations in the presence of strong Fusarium resource competition in plant monocultures. Similarly, these results suggest selection for Streptomyces-inhibitory Fusarium populations in the presence of strong Streptomyces resource competition in more diverse plant communities. Thus, landscape-scale variation in plant species richness may be critical to mediating the coevolutionary dynamics and selective trajectories for inhibitory and nutrient use phenotypes among Streptomyces and Fusarium populations in soil, with significant implications for microbial community functional characteristics.