Functional potential of archaeal KEGG enzymes in the Moringa oleifera rhizosphere revealed by metagenomic analysis

Archaea are a major domain of life that inhabit diverse and often extreme environments, contributing to biogeochemical cycles and participating in nutrient cycling within plant rhizospheric soils. This study applies metagenomic whole-genome shotgun sequencing to characterize the archaeal component of the rhizospheric microbiome associated with the wild plant species Moringa oleifera in Saudi Arabia. Based on KEGG-annotated enzymes, Thaumarchaeota and Euryarchaeota emerged as the predominant archaeal phyla in the rhizosphere, with higher abundance than in bulk soil. The most abundant archaeal enzymes were assigned to metabolic pathways related to nitrogen and sulfur metabolism, carbon transformations, and responses to oxidative stress, indicating a putative contribution to nutrient turnover and stress-related functions. Network analysis further identified archaeal chemotaxis-related regulators and two-component sensor kinases linked to the root–soil interface. Key enzymes detected included urease, glutamine synthetase, thiosulfate sulfurtransferase, and catalase-peroxidase. These findings suggest that archaeal communities form a distinct functional module within the M. oleifera rhizosphere, potentially influencing soil nutrient dynamics and plant performance. The chief limitation is reliance on DNA-based metagenomic data from a single site and time point, without multi-omics or detailed soil characterization, restricting temporal and ecological generalization. Nonetheless, the dataset provides a genome-scale view of archaeal functional potential and offers testable directions for future experimental and process-oriented studies.