posted on 2024-01-12, 13:40authored byJingjing Xue, Xiaopeng Guo, Guangxin Xu, Xi Chen, Lihang Jiao, Xixiang Tang
The bacterial wilt caused by Ralstonia
solanacearum seriously affects crop yield and safety
and is difficult to control.
Biological activity-guided screening led to the isolation of 11 phenolic
compounds including three undescribed compounds (carnemycin H–I
and stromemycin B) from the secondary metabolites of a marine-derived Aspergillus ustus. One new compound is an unusual
phenolic dimer. Their structures were elucidated by comprehensive
spectroscopic data and J-based configurational analysis.
The antibacterial activities of the isolated compounds against R. solanacearum were evaluated. Compound 3 exhibited
excellent inhibitory activity with an MIC value of 3 μg/mL,
which was comparable to that of streptomycin sulfate. Additionally, 3 significantly changed the morphology and inhibited the activity
of succinate dehydrogenase (SDH) to interfere with the growth of R. solanacearum. Molecular docking was conducted
to clarify the potential mechanisms of compound 3 with
SDH. Further in vivo experiments demonstrated that 3 could remarkably inhibit the occurrence of bacterial wilt
on tomatoes.