Detection of Antagonistic Compounds Synthesized by against subsp. by Metabolome and RNA Sequencing.

Biological control of plant diseases has gained attraction for controlling various bacterial diseases at a field trial stage. An isolated endophytic bacterium, 25 (Bv-25), from species had strong antagonistic activity against subsp. (), which causes citrus canker disease. When Bv-25 was incubated in Landy broth or yeast nutrient broth (YNB), the ethyl acetate extract of Landy broth exhibited higher levels of antagonistic activity against compared to that of YNB. Therefore, the antimicrobial compounds in the two ethyl acetate extracts were detected by high performance liquid chromatography-mass spectrometry. This comparison revealed an increase in production of several antimicrobial compounds, including difficidin, surfactin, fengycin, and Iturin-A or bacillomycin-D by incubation in Landy broth. RNA sequencing for the Bv-25 grown in Landy broth were performed, and the differential expressions were detected for the genes encoding the enzymes for the synthesis of antimicrobial compounds, such as bacilysin, plipastatin or fengycin, surfactin, and mycosubtilin. Combination of metabolomics analysis and RNA sequencing strongly suggests that several antagonistic compounds, especially bacilysin produced by , exhibit an antagonistic effect against .