Characterization and Assessment of 2, 4-Diacetylphloroglucinol (DAPG)-Producing VSMKU3054 for the Management of Tomato Bacterial Wilt Caused by .

Microbial bio-products are becoming an appealing and viable alternative to chemical pesticides for effective management of crop diseases. These bio-products are known to have potential to minimize agrochemical applications without losing crop yield and also restore soil fertility and productivity. In this study, the inhibitory efficacy of 2,4-diacetylphloroglucinol (DAPG) produced by VSMKU3054 against was assessed. Biochemical and functional characterization study revealed that produced hydrogen cyanide (HCN), siderophore, indole acetic acid (IAA) and hydrolytic enzymes such as amylase, protease, cellulase and chitinase, and had the ability to solubilize phosphate. The presence of the key antimicrobial encoding gene in the biosynthesis of 2,4-diacetylphloroglucinol (DAPG) was identified by PCR. The maximum growth and antimicrobial activity of was observed in king's B medium at pH 7, 37 °C and 36 h of growth. Glucose and tryptone were found to be the most suitable carbon and nitrogen sources, respectively. DAPG was separated by silica column chromatography and identified by various methods such as UV-Vis, FT-IR, GC-MS and NMR spectroscopy. When cells were exposed to DAPG at 90 µg/mL, the cell viability was decreased, reactive oxygen species (ROS) were increased and chromosomal DNA was damaged. Application of and DAPG significantly reduced the bacterial wilt incidence. In addition, was also found effective in promoting the growth of tomato seedlings. It is concluded that the indigenous isolate VSMKU3054 could be used as a suitable biocontrol agent against bacterial wilt disease of tomato.