AUTHOR=Han Songting , Yang Liang , Wang Yao , Ran Yuao , Li Shili , Ding Wei 

TITLE=Preliminary Studies on the Antibacterial Mechanism of a New Plant-Derived Compound, 7-Methoxycoumarin, Against Ralstonia solanacearum

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.697911

DOI=10.3389/fmicb.2021.697911

ISSN=1664-302X

ABSTRACT=<p><italic>Ralstonia solanacearum</italic> (<italic>R. solanacearum</italic>) is one of the most devastating plant bacterial pathogens and leads to serious economic losses in crops worldwide. In this study, the antibacterial mechanism of 7-methoxycoumarin, a new coumarin antibiotic, was preliminarily investigated by the observation of symptoms and physical and biochemical analyses. The results showed that 7-methoxycoumarin significantly suppressed bacterial growth of <italic>R. solanacearum</italic>, with the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values of 75 and 175 mg/L, respectively. Electron microscopy observations showed that the bacterial cell membrane was destroyed after 7-methoxycoumarin treatment. Biofilm formation of <italic>R. solanacearum</italic> was significantly suppressed by 7-methoxycoumarin at concentrations ranging from 25 to 100 mg/L. Furthermore, virulence-associated genes <italic>epsE</italic>, <italic>hrpG</italic>, and <italic>popA</italic> of <italic>R. solanacearum</italic> were significantly inhibited by 7-methoxycoumarin. The application of 7-methoxycoumarin effectively suppressed tobacco bacterial wilt progress in pot experiments, with relative control efficiencies of 83.61, 68.78, and 58.11% at 6, 8, and 10 days post inoculation, respectively.</p>