Diversity and ecological drivers of rhizospheric and endophytic microbiomes of desert plants in king Salman reserve, Saudi Arabia

Desert plants host specialized microbial communities that contribute to their survival under extreme heat, aridity, and nutrient limitation. In this study, we characterized the rhizospheric and endophytic microbiomes of three native Saudi desert species: Vachellia gerrardi, Haloxylon salicornicum , and Ziziphus spina-christi across three contrasting arid regions (Tabuk, Hail, and Arar). High-throughput amplicon sequencing of 16S rRNA and ITS markers generated a large dataset of high-quality reads, revealing bacterial communities primarily composed of Proteobacteria, Actinobacteria, Bacteroidetes, and Firmicutes. In contrast, Ascomycota and Basidiomycota were the dominant fungal phyla. Alpha-diversity analyses indicated apparent geographic variation, with Tabuk exhibiting the highest overall diversity and Arar showing enrichment for stress-associated taxa such as Rubrobacter and Truepera . Beta-diversity patterns indicated that environmental differences among regions had a greater influence on microbial community composition than host plant identity. Collectively, the findings underscore the pivotal role of ecological gradients in structuring desert microbiomes and provide a foundation for understanding microbial adaptation in arid ecosystems.