Different halophytes orchestrate microbial diversity in the rhizosphere of salinity-impacted soils

Abstract

Investigating rhizosphere communities in saline soils is crucial for identifying the taxonomic groups that play significant roles in halophyte adaptation. However, how the microbiome is structured under different saline conditions remains unclear. This study aimed to analyze bacterial communities in the rhizospheres of halophyte species in different saline environments. Five rhizospheres were analyzed using high-throughput sequencing of the 16S rRNA gene: S1, Salicornia fruticosa from a hypersaline tidal plain; S2, Sporobolus virginicus; S3, Cyperus ligularis from a hypersaline lagoon; S4, Salicornia fruticosa and S5, Blutaparon portulacoides from an abandoned salt pan. Bacterial communities in the S4 and S5 rhizospheres were influenced by P and K content, suggesting that specific nutrients can foster unique microbial structures, potentially assisting in adaptation to saline soils. The unique ASV (Amplicon Sequence Variant), richness, diversity, and microbial core of the S1 system, along with its similarities to S2 and S3, suggest common halophyte adaptation strategies across different saline environments, aiding targeted survival efforts. Identifying keystone species such as Thermoleophilia in S1, Alphaproteobacteria in S2 and S3, multiple species in S4, and the presence of Clostridia and Bacilli in S5 shed light on the roles these bacteria play in halophyte survival. Metagenomic prediction analysis demonstrated that chemoheterotrophy and aerobic chemoheterotrophy were the main prediction functions. In summary, this study revealed the intricate microbial structures in halophyte rhizospheres, enriching our understanding of saline ecosystems.