Alpine plant seed microbiomes, germination, and plant-soil feedbacks, Niwot Ridge and Green Lakes Valley, 2018.

Seed and soil microbiomes strongly affect plant performance, and these
effects can scale-up to influence plant community structure. However,
seed and soil microbial community composition are variable across
landscapes, and different microbial communities can differentially
influence multiple plant metrics (biomass, germination rate), and
community stabilizing mechanisms. We measured how microbiomes inside
seeds and in soils varied among alpine plant species and communities
that differed in plant species richness and density. Across 10 common
alpine plant species, we found a total of 318 bacterial and 128 fungal
operational taxonomic units (OTUs) associated with seeds, with fungal
richness affected by plant species identity more than sampling
location. However, seed microbes had only marginally significant
effects on plant germination success and timing. In contrast, soil
microbes associated with two different plant species had significant
effects on plant biomass, and their effect depended both on the plant
species and the location the soils were sampled from.