Rhizospheric glycosyltransferase repertoires as a resource for enabling sustainable bioprocessing and green biocatalyst discovery.

The rhizospheric microbiomes associated with wild plant species Moringa oleifera and Abutilon fruticosum, endemic to the arid northwestern Mecca region of Saudi Arabia, represent untapped reservoirs of genetic capability with significant implications for agriculture, biotechnology, medicine, and environmental sustainability. Leveraging high-throughput metagenomic sequencing and advanced bioinformatics, this study systematically cataloged carbohydrate-active enzymes (CAZymes), with a particular focus on glycosyltransferase (GT) families, within these root-associated microbial consortia. The analysis revealed pronounced compositional divergence between rhizospheric and bulk soil microbiomes, underscoring the influence of plant species and edaphic factors in shaping niche-specific microbial assemblages and functional repertoires. The two rhizospheric microbiomes were consistently enriched in all six CAZy classes, with lineage-specific CAZymes of GT families (GT2 and GT84 in M. oleifera and GT31, GT39, and GT66 in A. fruticosum). These lineage-specific CAZymes catalyze the synthesis of structurally diverse polysaccharides, including cellulose, chitin, β-glucans, mannans, and chondroitin, thereby positioning the rhizospheric microbiomes of Moringa oleifera and Abutilon fruticosum as promising reservoirs of biocatalysts for possible future applications in industrial applications, biomedical engineering, and environmentally sustainable technologies. The evolutionary history of these enzymes in hot, oligohydric soils suggests adaptation to thermal and water-limited conditions, which may render them particularly suitable for deployment in industrial and biotechnological bioreactors. These CAZymes are predicted to be positioned as pivotal assets for sustainable bioeconomy initiatives and possible therapeutic glycoengineering.