Soil properties and plant functional traits have different importance in shaping rhizosphere soil bacterial and fungal communities in a meadow steppe.

Unlabelled: Soil properties and plant functional traits are important factors influencing rhizosphere microbial diversity and composition. However, their divergent roles in shaping rhizosphere bacterial and fungal communities remain poorly understood. Additionally, the influence of plant resource acquisition strategies on these microbial communities is not well documented. We collected 147 rhizosphere soil, leaf, and root samples from around 18 plant species in a meadow steppe in northern China. We determined bacterial and fungal communities in the rhizosphere soil through high-throughput sequencing. Our analysis revealed that soil properties and plant traits differed in their importance for influencing the diversity and composition of rhizosphere bacteria and fungi. Specifically, soil properties had a more pronounced regulatory effect on bacterial diversity than on fungal diversity. Furthermore, soil properties exerted a stronger influence on the composition of rhizosphere fungal communities compared to plant traits, while both factors similarly affected bacterial community composition. This discrepancy might be attributed to differences in dispersal limitations between bacteria and fungi. We also found that plant resource acquisition strategies significantly impacted both diversity and composition of rhizosphere microbial communities, with plants employing "fast-growing" strategies exhibiting lower fungal diversity. Moreover, conservation-related traits of plants had a more pronounced effect on fungal community composition than root collaboration-related traits. These novel findings demonstrate that soil properties and plant traits play distinct roles in shaping rhizosphere soil bacterial and fungal communities. The linkages between plant resource acquisition strategy and rhizosphere microbial communities could enhance our understanding of the complex interactions between plants and their associated microorganisms.

Importance: Soil microorganisms in the rhizosphere play a crucial role in plant growth and health. However, the specific mechanisms that shape rhizosphere bacterial and fungal communities remain poorly understood. By linking plant resource acquisition strategies to microbial diversity and composition in the rhizosphere, we uncover the pivotal influence of plant conservation traits over root collaboration traits in shaping fungal communities, providing new insights into the complex interactions between plants and their associated microbial communities.