Interactive effects of fungal community structure and soil moisture on Wyoming big sagebrush performance

Abstract

Abstract Aims Local adaptation of plant populations to soil biotic conditions may complicate ecosystem restoration if seeds used in reseeding efforts are sourced from a different population than the one that succumbed to disturbance. Furthermore, climatic conditions may mediate the interaction between plants and soil microbial communities. This study aimed to assess how the composition of the local soil fungal community affects Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis) growth and its resource allocation to shoot and root growth under different moisture-availability conditions. Methods We explored sagebrush growth responses to inoculation with wet-adapted versus dry-adapted sagebrush-associated fungal communities in a 7-month greenhouse experiment. Seeds were planted with inoculum isolated from rhizosphere soil from either a relatively wet or a dry sagebrush-dominated site and subjected to a moisture regime representative of either the wet or dry site. Biomass, root morphology, and fungal community composition were assessed. Results Wet and dry sites hosted distinct in-situ fungal communities, and inoculum derived from different sites generated compositionally different fungal assemblages in the seedlings’ rhizospheres during the growth period. Compared to sterilized inoculum controls, live inoculum from either site enhanced seedling biomass, but only when soil moisture simulated that of the inoculum’s source site. Dry-site inoculum also produced longer, finer roots under dry-site conditions. Conclusions Moisture similar to the fungal inoculum’s source was necessary for fungi to positively impact sagebrush growth and root characteristics. Applying fungal inoculum adapted to an intended restoration site’s moisture could help seedlings optimize water uptake and productivity, encouraging sagebrush establishment.