The Impacts of Soil Microbial Communities on Translocated Sagebrush (Artemisia tridentata) Seedlings Vary Along Gradients of pH but Not Organic Matter

Climate factors are often the focus of local adaptation studies, but there are additional biotic and abiotic factors, including microbial communities and soil properties, that may generate selection in plant populations. pH and soil organic matter (SOM) are important influencers of microbial communities. We investigated the influence of pH and SOM on plant-microbe interactions and local adaptation of big sagebrush to microbial communities. Sagebrush seeds and autoclaved soils from 4 sites were reciprocally transplanted in a greenhouse experiment. Half of these soils were treated with intact soil inoculum to identify microbial impacts and how these effects varied when sagebrush plants were translocated into new soils. Soil samples were tested for pH and organic matter to identify the abiotic factors that may drive local adaptation. Soil microbial communities influence sagebrush seedling survival negatively in more acidic soils and have weak positive effects in more alkaline soils. Sagebrush seedlings showed signs of local adaptation to microbial communities that come from soils similar to their home pH. There were no clear effects of SOM on seedling survival or influence of microbial communities at this life-history stage. This work has implications for the translocation of sagebrush seeds in restoration projects across the Great Basin.