Proteome analysis for antifungal effects of Bacillus subtilis KB-1122 on Magnaporthe grisea P131.

Rice blast, caused by Magnaporthe grisea threatens rice production worldwide. It is important to develop novel and environment-safe strategies to control the fungus. Here we reported that Bacillus subtilis KB-1122 could strikingly inhibit the growth of M. grisea P131 in agar diffusion assays. To further understand the molecular mechanism on the suppressive role of B. subtilis on M. grisea, the antagonist-pathogen interaction of the two strains was studied by using comparative proteome analysis in this report. The cellular and culture supernatant (CSN) proteins were prepared from co-culture and subjected to two-dimensional polyacrylamide gel electrophoresis. Proteome analysis revealed 33 cellular and 18 CSN proteins showing changes upon co-culture respectively. Importantly, down-regulated cellular proteins came from M. grisea, whereas up-regulated proteins derived from B. subtilis. Results suggested that glyceraldehyde-3-phosphate dehydrogenase and serine protein kinase might contribute to antifungal activity of B. subtilis KB-1122. Of CSN proteins identified, the endo-1,4-beta-glucanase (involved in degradation of polysaccharides) was up-regulated consistently at different times of incubation. This suggests that this enzyme plays an important role in the interaction between B. subtilis KB-1122 with M. grisea P131.