Rice Genotype-Dependent Phyllosphere Microbiome Assembly and Isolation of Antagonistic Burkholderia for Sheath Blight...

Rice sheath blight (RSB), caused by Rhizoctonia solani, causes 10-50% yield losses globally. Using 16S rRNA sequencing of 100 rice cultivars, we found that resistant varieties harbor significantly more diverse bacterial communities (3230 OTUs; 2064 unique) than susceptible cultivars (599 OTUs; 36 unique). Resistant varieties were enriched in beneficial Burkholderiaceae, Bacillaceae, and Pseudomonadaceae, while Sphingobacteriaceae and Enterobacteriaceae were predominant in the susceptible rice varieties. From the 260 bacterial isolates, Burkholderia vietnamiensis J14EPLEAF2 presented potent antifungal activity (77% inhibition), suppressed lesion development, and abolished sclerotia formation. This strain displayed multiple plant growth-promoting traits, enhanced seed germination, and primed defense responses by upregulating PR5 and PR10. Hypersensitive response assays confirmed B. vietnamiensis as non-pathogenic, unlike B. gladioli and B. cepacia. This study identifies B. vietnamiensis J14EPLEAF2 as a promising, safe biocontrol agent for sustainable rice disease management.