Metagenomic Analysis of Microbial Community Dynamics in Konjac Rhizosphere During Soft Rot Disease Progression

Amorphophallus konjac, the sole glucomannan-rich species in the family Araceae, faces significant yield and quality losses due to soft rot disease. Understanding the relationship between soil microbial communities and soft rot incidence is critical for sustainable konjac production. Metagenomic analysis was employed to systematically investigate rhizosphere microbial dynamics associated with soft rot progression. Microbial community richness peaked at the mature stage of diseased plants compared to healthy and latently infected counterparts. Principal coordinate analysis revealed greater variability in rhizosphere communities of diseased plants, with distinct separation from healthy/latently infected samples. At the phylum level, Chloroflexi and Acidobacteria abundances in healthy mature plants exceeded those in diseased plants by 11.54% and 4.6%, respectively, while pathogenic Rhizopus arrhizus and Rhizopus microsporus were significantly enriched in diseased mature plants. Correlation analyses demonstrated predominantly negative associations between bacterial species and soil factors, contrasting with positive fungal correlations. KEGG pathway annotation identified carbohydrate metabolism and amino acid synthesis as core microbial functions in the konjac rhizosphere. These findings suggest that Chloroflexi and Acidobacteria enhance disease resistance, whereas Rhizopus species promote soft rot development. Our results provide actionable insights for designing microbiome-based strategies to mitigate konjac soft rot, reducing reliance on conventional agrochemicals.