Indonesia Conference Directory

The capacity of Serratia plymuthica UBCR_12 in suppressing anthracnose causal agent, Colletotrichum gloeosporioides is regulated molecularly through protein expression. Regarding its suppression, the efficacy of this antianthracnose bacteria is greatly affected by various environmental factors, particularly the presence of bacterial main nutrients (carbon and nitrogen). This study was aimed to investigate the expression profile of antianthracnose-related proteins in S. plymuthica UBCR_12 under different modified medium. Antagonistic activity of this bacteria against C. gloeosporioides was assessed using agar spot method in PDA medium supplemented with several concentrations of peptone or glucose. Pathogenic fungi-bacteria co-culture was performed under the same condition as an antagonistic assay to induce the extracellular proteomes expression related to this antianthracnose trait. Proteome profiles were visualized using SDS-PAGE and 2-DE, then a highly differential protein spot was further analyzed using MALDI-TOF-MS. Prediction of protein classification and possible hypothetical pathway were performed in-silico. The highest suppression (42.3% at 9th-day post application) resulted in 2% glucose-supplemented medium, however 2% peptone-supplemented medium conferred a quicker suppression (at 5th-day post application) with quite lower inhibition efficacy (40%). Differential expression of 42 kDa protein band recorded during peptone addition was predicted to be flagellin protein, which might correlate with a rapid stimulus of suppression activity. This protein involved in the quorum-sensing mechanism by triggering the greater rate of cell division resulting in bacterial colonization and motility approaching the fungal pathogen.