Antimicrobial Activity of Bacillus sp. to Xanthomonas oryzae pv. oryzae, Pseudomonas syringae pv. glycines, and Pseudomonas fluorescens.

Abstract

Leaf blight disease caused by bacterial plant pathogen such as X. oryzae pv. oryzae and P. syringae pv. glycines had deathly effect to plants. The pathogens can be controlled by biological control using P. fluorescens or antimicrobial substances. The research studied the inhibition ability and production of antimicrobial substances produced by Bacillus sp. againts bacterial plant pathogen such as X. oryzae pv. oryzae, P. syringae pv. glycines, and biological control P. fluorescens. As many as 31 Bacillus sp. isolates isolated from forest soil was determined their antimicrobial activity against indicator bacteria using double layer method. The result showed that 13 isolates was able to inhibit Staphylococcus aureus, Eschericia coli, and X. oryzae pv. oryzae growth, 8 isolates could inhibit P. fluorescens A growth, 9 isolates could inhibit P. fluorescens B growth, and 8 isolates could inhibit P. syringae pv. glycines growth. Bacillus sp. F13 had the fastest inhibition and good efficiency against all indicator bacteria. Mixed culture competition test showed that this isolate had a broad spectrum inhibition activity, it was able to inhibit Gram positive and Gram negative bacteria. The isolate could inhibit growth of P. syringae pv. glycines and X. oryzae pv. oryzae up to 100%. The antimicrobial substance the isolate was produced in the late logarithmic growth phase.