Deoxymikanolide adversely altered physiology and ultrastructure of Ralstonia solanacearum
Yan Li1, Yun-Fei Zeng2, Zi-Yi Wang3
1State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang 550014, China; Department of Pesticides, Key Laboratory of Pesticide Chemistry and Application, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences, Guizhou Provincial Engineering Research Center for Natural Drugs, Guiyang 550014, China.
Abstract:
Deoxymikanolide (DEO) was isolated from Mikania micrantha Bunge and identified as a novel antibacterial compound previously. However, the mode of antimicrobial mechanism of DEO was not clear but hypothesized to affect the morphology and physiology of Ralstonia solanacearum cells. In this study, we confirmed our hypothesis via transmission electron microscopy (TEM) observation and comprehensive physiological analyses, including electric conductivity, glycan and phosphorus metabolism, activities of antioxidant enzymes (catalase, peroxidase, and superoxide dismutase), intrabacterial reactive oxygen species (ROS), and malondialdehyde (MDA) levels. We found that glycan and phosphorus metabolism, electric conductivity, intracellular ROS and MDA levels of R. solanacearum cells were significantly increased, while the activities of three antioxidant enzymes were significantly inhibited by DEO treatment. Moreover, TEM analysis showed that DEO treatment led to an early-stage of cell shrinkage, intermediate-stages of cytoplasmic damage, and a final-stage of cell disruption. Altogether, our data presented here indicate that DEO could adversely affect the physiology and morphology of R. solanacearum cells and be treated as an alternative antibacterial treatment in the future.
