Microbial populations in the rhizosphere play important roles in soil fertility, nutrient cycling, and plant health. Despite the crucial roles these bacteria play, it is unclear how the rhizosphere was created and acquired. Deschampsia Antarctica (Da) and Colobanthus quitensis (Cq), the only two native Antarctic plants, served as models for our investigation into the diversity of microbial communities and probable sources. At six locations in the Byers Peninsula, Livingston Island, Antarctica, we examined the rhizosphere and bulk soil microbiomes, looking at both specific plant species and their associations (Da.Cq). Our findings indicate that the richness and diversity of bacterial communities in the rhizosphere were impacted by host plant species. When compared to Cq and Da.Cq rhizospheres, the Da rhizosphere displayed the least amount of bacterial variety and richness. The rhizosphere of Da had a larger fungal diversity than the rhizosphere of Cq, whereas for rhizosphere fungi, plant species solely affected diversity. In addition, we discovered that environmental geographic forces (such as sampling location, latitude, and altitude) and, to a lesser extent, biotic stressors (such as plant species), influenced the species turnover between microbial communities. Furthermore, our study demonstrates that the local soils that helped to homogenise the community composition of the various plant species growing at the same sampling site were the sources of the bacterial communities in the rhizosphere. For Da and Da.Cq, however, the sources of rhizosphere fungi were found in nearby and far-off soils (for Cq). Here, the types of host plants have a specific role in bringing microbial populations to the rhizosphere. However, the fact that unidentified sources contributed to the fungal rhizosphere, particularly in Da and Da.Cq, suggests that important stochastic processes were likely involved in the acquisition of these microorganisms. Our research demonstrates that the richness and composition of microbial communities in the rhizosphere vary. These variations are mostly explained by the microbial ecology of the soils that support them, in conjunction with effects unique to each plant species. Both plant species get the microorganisms that make up their rhizosphere from nearby soils. The acquisition procedure seems to be more difficult for fungus. Due to stochastic processes and recognised sources from soils all across the Byers Peninsula, we found a considerable contribution from undiscovered fungus sources.
