Severity reduction of Frogeye Leaf Spot of soybean by inoculation with the native strain Bacillus sp.CHEP5

MARÍA LAURA TONELLI; ADRIANA FABRA

Simposio; 32nd New Phytologist Symposium. Plant interactions with other microorganisms: molecules, ecology and evolution; 2013

Frogeye Leaf Spot (FLS) caused by Cercospora sojina Hara limits soybean production. The aim of this study was to evaluate the ability of the biocontrol agent Bacillus sp. CHEP5 to induce plant defense response against C. sojina. Soybean plants were inoculated in the roots with Bacillus sp. CHEP5.Trifoliate leaves were challenged with C. sojina CCC 172-09. FLS severity was evaluated by analyzing the plant infection level, damaged leaf area and chlorophyll content. AOS gene expression was evaluated by Real Time PCR in induced and challenged plants. Plants inoculated with Bacillus sp. CHEP5 and C. sojina, showed a reduced disease level, a decrease in the damaged leaf area without changes in their chlorophyll content. On the other hand, AOS gene expression was not primed during Bacillus sp. CHEP5 induction. In conclusion, Bacillus sp. CHEP5 reduced the severity of FLS in soybean, suggesting that this bacterium induced systemic resistance in the plants. However, this induction did not involve the primed expression of AOS gene under the conditions used in this study.