Comparisons of soil microbial compositions in rhizospheres of sugarcane cultivars with different abilities to resist smut

Sugarcane smut, caused by the fungus Sporisorium scitamineum, is a devastating disease that limits sugarcane production and causes significant yield losses worldwide. This urgent threat highlights the critical need for novel sustainable control strategies. While utilizing beneficial plant-associated microbes shows promise for enhancing disease resistance, the contribution of the sugarcane rhizosphere microbiome in smut resistance remains poorly understood. In this study, rhizosphere microbial communities of sugarcane cultivars with contrasting resistance to smut were comparatively analyzed using high-throughput amplicon sequencing of the 16S rRNA gene and ITS region. Analysis of microbial co-occurrence networks analysis revealed that the resistant cultivars maintained more complex and stable networks than the susceptible cultivars. The rhizosphere microbiome of smut-resistant cultivars was predominantly enriched in beneficial genera such as Trichoderma, Penicillium, Talaromyces, Psathyrella, and Sphingomonas whereas that of susceptible cultivars contained more Streptomyces and Gibberella. Functional prediction also revealed distinct metabolic functions between the two microbiomes. These findings demonstrate that network stability and enrichment of antagonistic microbes constitute key determinants of rhizosphere-mediated smut resistance. Our study provides critical insights for developing microbiome-driven breeding strategies and biological control measures against this economically important disease.