Microbial Differences in Rhizospheric and Ednophytic Microbiota in Healthy Chinese Yam Roots and Those Affected by Yam End Black Disease

Yam end black disease (YEBD) is a devastating soil-borne disease that severely compromises the yield of Chinese yam (<i>Dioscorea opposita</i> Thunb.). Despite its agricultural importance, the etiological agents and molecular mechanisms underlying YEBD remain poorly understood. In this study, we employed an integrated multi-omics approach, combining transcriptomics and microbiome analysis, to dissect the host responses and microbial shifts associated with YEBD. De novo transcriptome assembly revealed significant enrichment of differentially expressed genes involved in polyamine metabolism and hormone signaling pathways. Microbiome profiling identified a substantial increase in nematodes (<i>Meloidogyne</i> spp.) in diseased samples, which correlated negatively with the beneficial fungus Cladosporium. Bacterial community analysis showed an increase in Proteobacteria and Bacteroidetes and a decrease in Actinobacteria and Firmicutes in YEBD-affected roots. Notably, the rhizosphere microbiome was less affected than the endophytic community, suggesting that internal microbial dysbiosis plays a critical role in disease progression. These findings provide new insights into the interactions among yam, nematodes, and microbes, offering potential strategies for biocontrol and disease management.