Dynamics in diversity, co-occurrence pattern, and community assembly of a perennial desert plant root-associated bacteria

Abstract

The microbial communities that inhabit the rhizosphere and roots contribute to plant survival. However, it remains largely unclear about the ecological processes that govern the assembly of these root-associated bacterial communities for desert plants. Alhagi sparsifolia Shap. is a dominant perennial phreatophyte in the Taklamakan Desert, Central Asia. Here we analyzed the bacterial communities in three compartments (bulk soil, rhizosphere, and root) at different growth times of A. sparsifolia using high-throughput sequencing. The results showed that the assembly of root-associated bacterial communities was shaped by host growth time and compartment, and host growth time (27.04%) contributed more to community variation than compartment (20.04%). The community composition at 30 days and perennial was significantly different from that at other periods (P < 0.05). Along the bulk soil–rhizosphere–root continuum, there was a downward trend in bacterial α-diversity and the influence of soil factors on community structure. More complex networks were found in the rhizosphere and 90-day communities. The homogeneous selection was predominant in the assembly process of 30 days (41.21%), perennial (46.83%), and rhizosphere (46.90%) communities. Overall, our work provides empirical evidence on host selection and environmental influence on the community assembly of perennial desert plants and has crucial implications for future management of desert vegetation.