Rhizosphere and root-associated microbial community structures and plant physiology responses to Large Patch disease in zoysiagrass

Large Patch disease caused by Rhizoctonia solani devastates zoysiagrass turf, yet its microbiome-mediated pathogenesis remains elusive. This study investigated the effects of R. solani strain ZS-1 on zoysiagrass physiology and rhizosphere microbial communities. Pathogen inoculation significantly inhibited plant growth (p < 0.05), reducing net photosynthetic rate (32.1%), chlorophyll content (19.4%), and photochemical efficiency (Fv/Fm). Concurrently, the antioxidant defense was activated, with catalase (CAT), and phenylalanine ammonia-lyase (PAL) activities increasing by 2.1- and 3.3-fold, respectively. Furthermore, soil nutrient dynamics shifted, showing a 40% decline in available nitrogen and 22% increase in phosphorus. Integrating 16S/ITS amplicon sequencing with physiological assays, we decoupled tripartite interactions among pathogen invasion, microbiome restructuring (n = 3 biological replicates), and host responses. The results showed that the bacterial Chao1 index increased significantly while the Shannon index declined. Key microbial shifts included declines in Ascomycota and Basidiomycota fungi and enrichment of Actinobacteria and Chloroflexi in the rhizosphere. Dominant bacterial genera such as Geobacter and Anaerolinea were linked to enhanced nutrient cycling and stress tolerance. Soil properties, including available potassium and phosphorus, correlated with specific microbial taxa, such as Glomeromycota, suggesting their role in nutrient modulation under pathogen stress. These findings highlight the complex interplay between R. solani invasion, microbial community restructuring, and zoysiagrass physiological responses. This study provides foundational insights into leveraging soil microbiome management to improve zoysiagrass resilience against Large Patch disease, offering practical strategies for sustainable turfgrass cultivation.