The exploration of Bacillus spp. as antagonist agents against Xanthomonas axonopodis pv. glycines from the weed phyllosphere in soybean plantation
Bacterial pustules caused by Xanthomonas axonopodis pv. glycines (Xag) is one of the important diseases in soybean plants. Bacillus bacteria from the soybean phyllosphere have the potential to inhibit these pathogens. Weed phyllosphere in soybean plantations is also a good habitat for Bacillus life. The purpose of this study was to obtain Bacillus from the weed phyllosphere which has the potential as an antagonistic agent against Xag. The study methods included exploration, screening, and physio-biochemical identification. The results obtained 31 isolates and 22 of them were able to inhibit Xag with various inhibitory properties. Five strains of Bacillus spp. had large inhibitory effects against Xag, namely strain Bp 2(2), Jg3(3), Bg d1(1), Jg 1(3) and Jg 1(4)1. The Bacillus strain Bp2(2) had the largest inhibition zone witht 15 mm and strain Jg1(4)1 had the fastest colony growth with 68 mm. Five Bacillus spp had different growth capability based on the environmental condition and carbon source. The physio-biochemical identification results indicated that Bacillus strain Jg 3(6), Bg d 1(1), Jg 1(3), Jg 1(4)1 had the similar characteristics to B. licheniformis, while strain Bp 2(2) had the similar characteristics to B. coagulans.