The functional structure of foxtail millet rhizoplane microbiome and its association with yield.

Root-associated microbial communities profoundly influence plant growth and productivity. Although the rhizosphere microbiome has been extensively studied, the functional distinctiveness and host-specific role of the closely adhering rhizoplane microbiota remain unclear. In this study, we performed deep metagenomic sequencing of both the rhizosphere and rhizoplane microbiomes in foxtail millet ( IMPORTANCE: Plant roots selectively recruit diverse and beneficial microorganisms from the surrounding soil, assembling a distinctive rhizosphere microbiome. Substantial research, primarily utilizing amplicon sequencing, has elucidated the taxonomic composition of these rhizosphere communities across a wide range of plant species. The functional architecture, assembly processes, and coexistence mechanisms of the rhizoplane microbiome remain poorly understood, and their link to host plant traits is unclear. We elucidate the taxonomic and functional structural disparities between the rhizosphere and rhizoplane microbiomes, thereby clarifying the composition and functional roles of the rhizoplane microbiome, and further examine the association between the rhizoplane microbiome and millet yield. A deeper understanding of root-associated microbial communities may inform the development of effective agricultural probiotics, thereby enhancing sustainable farming practices. Additionally, the candidate biomarkers identified in this work offer potential targets for improving cultivation practices and supporting the long-term agricultural sustainability of foxtail millet.