Unraveling the Rhubarb (Rheum officinale Baill.) Root and Rhizosphere Microbial Communities in Response to Pathogen Exposure.

Abstract

This study investigated the microbial community composition and structure in healthy and diseased rhubarb (Rheum rhabarbarum) root systems, examining both root tissue and rhizosphere environments. Alpha diversity analysis revealed significantly higher microbial abundance in the rhizosphere compared to root tissues, with notable differences between healthy and diseased plants. Principal coordinate analysis demonstrated that bacterial community composition was primarily influenced by ecological niches (47.5% variation explained), whereas fungal communities segregated based on plant health status. Network analysis revealed increased bacterial community complexity in diseased plants rhizosphere (579 nodes, 13,016 edges) compared to healthy plants (542 nodes, 8700 edges), while fungal networks showed opposite trends with significant reduction in diseased conditions (147 nodes, 30 edges vs. 205 nodes, 418 edges). Correlation analysis identified significant associations between specific microbial taxa and soil properties, with notable positive correlations between certain bacteria (Oscillospirales) and fungi (Barnettozyma, Mortierella) with soil organic matter and nutrient availability. Pathogenic taxa, including Fusarium and members of Burkholderiales, showed negative correlations with beneficial microorganisms, suggesting potential antagonistic relationships. These findings provide crucial insights into the complex interactions within the rhubarb root microbiome and their implications for plant health, contributing to our understanding of root rot disease dynamics and potential management strategies.