Researchers from the Brazilian Agricultural Research Corporation and the University of São Paulo have identified three bacteria that can help suppress a soil-borne pathogen responsible for wheat root rot, potentially paving the way for new agricultural inoculants.
The findings were reported by André Julião in an article about the research published by the Agency FAPESP. The study found that wheat grown in soil containing the bacteria and the pathogen Bipolaris sorokiniana had 60% fewer disease symptoms than plants exposed only to the pathogen.
The researchers selected Streptomyces virginiae, Paenibacillus ottowii and Pseudomonas inefficax from bacteria identified in an earlier study as having plant growth-promoting and pathogen-suppressing potential.
P. inefficax was the most effective of the three, significantly increasing root biomass and restoring microbiome functions associated with plant protection. Along with S. virginiae, it also showed a high abundance of genes associated with plant growth promotion and increased biosynthetic gene clusters involved in producing potentially beneficial plant compounds.
The researchers found that the bacteria did not eliminate B. sorokiniana from the soil. Instead, the bacteria altered the soil microbiome in ways that helped protect wheat plants from the pathogen.
The bacteria were described as acting as ecological engineers, changing the microbial community and strengthening the plant's defenses. The findings indicate that controlling disease may depend not only on eliminating pathogens but also on promoting microbial communities that help plants resist infection.
The bacteria were originally isolated from soil associated with ancestral wheat varieties. The samples came from two landrace varieties obtained from Turkey and Iran, countries near the center of origin of wheat.
An earlier study by the research group found that lower soil microbiome diversity increased the severity of B. sorokiniana infection and that P. inefficax could suppress the pathogen.
The three bacteria evaluated in the latest research are part of EMBRAPA's portfolio of assets and can be licensed by companies interested in developing products based on the findings.
Researchers are continuing to investigate which metabolites produced by wheat support beneficial bacteria and are working to predict the metabolic pathways activated during the interaction. The work could support development of technologies for controlling and preventing diseases in agricultural crops.
Root rot is among the most common diseases affecting wheat. Brazil produced 7.87 million metric tons of wheat in 2025, while more than 800 million metric tons were harvested worldwide.
Source: Agency FAPESP, "Soil bacteria protect wheat from pathogenic fungus"