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=Volume 12 - 2021

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=Ralstonia solanacearum (R. solanacearum) 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 the bacterial growth of R. solanacearum, with the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values of 75 mg/L and 175 mg/L, respectively. Electron microscopy observations showed that the bacterial cell membrane was destroyed after 7-methoxycoumarin treatment. Biofilm formation of R. solanacearum was significantly suppressed by 7-methoxycoumarin at concentrations ranging from 25 mg/L to 100 mg/L. Furthermore, virulence-associated genes of R. solanacearum including EpsE, HrpG and PopA, were significantly inhibited. 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 d, 8 d, and 10 d post inoculation with R. solanacearum, respectively.