Arctic and subarctic soils are undergoing rapid changes that influence vegetation, bacteria, and their interactions with each other and the environment. Our objective was to understand how rhizosphere bacterial communities from diverse Alaskan boreal and tundra habitats and common Alaskan plant species interact with an anthropogenic soil stressor. A variety of soil types associated with plant communities from Interior and Arctic Alaska were selected. Soils were seeded with a forb, grass, or tree, spiked with antimony (Sb) or kept as a control, and grown for 60 days under warm conditions. Plant growth and Sb uptake, rhizosphere prokaryote composition, and mycorrhizal colonization data were collected. Antimony altered rhizosphere bacterial community richness, diversity, and composition, dependent on soil type and plant identity. Of 20 rhizosphere bacterial orders, Burkholderiales proved most responsive to Sb, but the responses varied by plant species. Plant species' uptake of Sb were strongly influenced by soil biological, chemical, and physical properties. Picea glauca (white spruce) accumulated hyperaccumulator-level Sb concentrations in its roots in 2 of 6 soils. Future biotechnology applications to mitigate land degradation in this environment must acknowledge the complex interactions between vegetation, soils, microbes, and climate for successful utilization.
Read full abstract