LB 30-295 - Microbial community differentiation in response to plant community composition and precipitation manipulation in a prairie field experiment

Background/Question/Methods:

Soil microbiome dynamics play a major role in structuring plant communities through microbiome feedbacks. Understanding resilience of plant communities to a changing climate will require understanding the pace of microbiome differentiation in the field and the sensitivity of microbiome feedbacks to environmental drivers. We test the temporal development and the dependence of microbiome differentiation on precipitation levels within full factorial manipulation of species richness (1, 2, 3, or 6 species), plant family composition (single families or mixed family plots), and precipitation (50% or 150% ambient). The experiment was planted in spring of 2018. We collected soil in fall of 2018 & 2020, extracted DNA, and used amplicon sequencing techniques & bioinformatics pipelines specific to fungi, AMF, bacteria, & oomycetes. We tested whether 1) microbial diversity increases with plant species richness 2) fungal pathogen abundance is higher when plants are closely related 3) differences in microbial composition 4) changes from 2018 to 2020 with precipitation.

Results/Conclusions:

After only 4 months since planting, soil fungal pathogen & bacteria diversity increased with planted species richness, but root oomycete, AMF, & bacteria diversity decreased. All microbial groups differentiated between plant family composition. In particular, fungal pathogen abundance changed in response to plant family composition, consistent with an important major role of host-specific pathogen accumulation in structuring plant communities. In 2020 oomycete & bacteria diversity increased with 150% precipitation, but AMF & fungal diversities were higher in 50% precipitation. Microbiome composition diverged between plant family & precipitation treatments. Our results identify that microbiome differentiation is rapid and depends on precipitation, suggests that microbiome feedback will be modified by climate, with implications for biodiversity maintenance and restoration practice.