Sympatric Soil Microbe Interactions between Streptomyces and Fusarium Isolates

<p>Interkingdom interactions between soil bacteria and fungi may play a critical role in occurrence of disease suppressive soils, yet our understanding of these interactions remains limited. <em>Streptomyces</em> are well-known producers of antimicrobial compounds important to medicine and agriculture. Production of these secondary metabolites is often mediated by quorum sensing. Most <em>Streptomyces</em> research occurs in single species experiments, yet new metabolites have been discovered in interspecies co-culture experiments. Interspecies, intergenic, and interkingdom co-culture research will likely reveal many valuable compounds, and strengthen our understanding of complex ecological interactions in soil microbiomes. Interactions between sympatric <em>Streptomyces</em> and <em>Fusarium</em> isolates from disease suppressive soils were investigated in this study. Dual layer agar inhibition assay revealed inhibition of <em>Streptomyces</em> by <em>Fusarium</em> in all pairwise combinations, while only 46% of pairwise combinations showed <em>Fusarium</em> inhibition by <em>Streptomyces</em>. <em>Streptomyces</em> isolate S2-2 was shown to produce antifungal compounds in a population density dependent manner, likely governed by quorum sensing. Exposure of S2-2 broth culture to conditioned media which likely contained autoinducers from mature S2-2 culture was shown to cause a significant increase in antifungal production earlier than control groups. Simultaneous inoculation of S2-2 and <em>Fusarium</em> isolate F10-8 was shown to cause a significant decrease in antifungal production. Exploring these interactions is of great importance for antimicrobial drug discovery, identifying useful microbial biological control agents, and improving our ability to promote disease suppression in soils.</p>

Name thesis:degree_name

Master of Science

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Biology

Year dc:date.available

2023

Author dc:creator

• Olk-Szost, Lehren A

Contributors dc:contributor

• Donna Maki

• Streptomyces
• Fusarium
• Antifungal
• Sympatric
• Microbial Biological Control Agent
• Co-culture
• Disease Suppressive Soils
• Agriculture
• Bacteriology
• Biochemistry
• Biodiversity
• Biology
• Ecology and Evolutionary Biology
• Environmental Microbiology and Microbial Ecology

Repository record dc:identifier

https://commons.nmu.edu/theses/757

OAI identifier oai:identifier

oai:commons.nmu.edu:theses-1805