Metagenomic Analysis of the Rhizosphere Microbiome of Poa alpigena in the Qinghai Lake Basin Grasslands

Poa alpigena Lindm is a dominant forage grass in the temperate grasslands of the Qinghai Lake Basin, commonly used for grassland restoration. Soil microorganisms are crucial in material cycling within terrestrial ecosystems. This study aimed to investigate the effects of P. alpigena on the microbial community composition and structure in rhizosphere and non-rhizosphere soils in the Qingbaya grassland area. Using high-throughput sequencing, we identified microbial gene pools and compared microbial diversity. Metagenomic analysis showed that non-rhizosphere soil contained 35.42–36.64% known microbial sequences, with bacteria making up 79.25% of the microbiota. Alpha diversity analysis indicated significantly higher microbial richness and diversity in non-rhizosphere soil, influenced by electrical conductivity, total carbon, and total nitrogen content. LEfSe analysis revealed that Alphaproteobacteria and Betaproteobacteria were major differential taxa in rhizosphere and non-rhizosphere soils, respectively. Key metabolic pathways in rhizosphere microorganisms were related to AMPK signaling, secondary metabolite biosynthesis, and starch metabolism, while non-rhizosphere microorganisms were involved in aromatic compound degradation, purine metabolism, and microbial metabolism in diverse environments. The enrichment of microbial taxa and functional pathways related to methane oxidation in rhizosphere soil suggests a potential role of P. alpigena in shaping microbial processes linked to greenhouse gas regulation, although direct evidence of methane flux changes was not assessed. Similarly, the presence of aromatic compound degradation pathways in non-rhizosphere soil indicates microbial potential for processing such compounds, but no direct measurements of specific contaminants were performed.