Rhizospheric Bacteria Isolate EA105 Inhibits Blast Infections in Rice

Magnaporthe oryzae is a fungus that causes blast, which can lower the yield for as much as 30%. Fortunately, naturally-occurring rice soil bacteria may provide a sustainable solution to reduce the damage of blast disease. Rhizospheric microbiomes, with their interactions with the plant roots, can modulate both growth promotion and disease suppression. This study evaluates the capacity of naturally-occurring bacteria in reducing M. oryzae infections. 

Rhizospheric bacteria isolates were obtained from field grown rice plants. These were tested for biocontrol activity against M. oryzae pathovar 70-15. The Pseudomonas isolate EA105 displayed antibiosis with 90% reduction of M. oryzae appressoria formation in vitro. Although hydrogen cyanide (HCN) is associated with biocontrol pseudomonads, the biocontrol activity of EA105 seems to be independent of HCN production. In the field test, EA105 reduced the number of blast lesions formed by 33%. Another bacteria, the Pantoea agglomerans isolate EA106, reduced lesions by 46%. Both isolates triggered jasmonic acid (JA) and ethylene (ET) dependent induced systemic resistance (ISR) response in rice.

EA105 was the most effective isolate in inhibiting the growth and appressoria formation of M. oryzae independent of cyanide production. The application of native bacteria as biocontrol agents in combination with current disease protection strategies could aid in global food security.

For more information about the study, you can visit: http://www.biomedcentral.com/1471-2229/14/130/abstract