The antibacterial mechanism of phenylacetic acid isolated from Bacillus megaterium L2 against Agrobacterium tumefaciens

PeerJ

article

Hang Pan¹  Yang Xiao²  Ailin Xie¹  Zhu Li¹  Haixia Ding⁴  XiaoJu Yuan⁵  Ran Sun¹  Qiuju Peng¹ 

[1] Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region ,(Ministry of Education), College of Life Sciences/Institute of Agro-bioengineering, Guizhou University, Guiyang, Guizhou Province;Institution of Supervision and Inspection Product Quality of Guizhou Province;Guizhou Key Laboratory of Agricultural Biotechnology, Guizhou Academy of Agricultural Sciences;Department of Plant Pathology, College of Agriculture, Guizhou University;Development Center of Planting, Huishui County of Qiannan Prefecture, Guizhou Province

关键词: Bacillus megaterium;    Metabolite;    Phenylacetic acid;    Agrobacterium tumefaciens;    Antibacterial mechanism;   

DOI  :  10.7717/peerj.14304

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

BackgroundAgrobacterium tumefaciens T-37 can infect grapes and other fruit trees and cause root cancer. Given the pollution and damage of chemical agents to the environment, the use of biological control has become an important area of focus. Bacillus megaterium L2 is a beneficial biocontrol strain isolated and identified in the laboratory, which has a good antibacterial effect on a variety of plant pathogens. The antibacterial metabolites of L2 were separated and purified to obtain a bioactive compound phenylacetic acid (PAA).MethodsThe potential antibacterial mechanism of PAA against A. tumefaciens T-37 strain was determined by relative conductivity, leakage of nucleic acids, proteins, and soluble total sugars, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and reactive oxygen species (ROS).ResultsPAA showed good antibacterial activity against strain A. tumefaciens T-37 with IC50 of 0.8038 mg/mL. Our data suggested that after treatment with PAA, the relative conductivity, nucleic acid, protein, and total soluble sugar of T-37 were increased significantly compared with the chloramphenicol treatment group and the negative treatment group. The total protein synthesis of T-37 cells was inhibited, the consumption of phosphorus decreased with the increase of incubation time, and the content of ROS was significantly higher than that in the negative treatment group. Meanwhile, the activity of two key enzymes (MDH and SDH) involved in the tricarboxylic acid cycle (TCA cycle) decreased. In addition, T-37 cells were found to be damaged by scanning electron microscopy observation. Our results showed that PAA can destroy cell membrane integrity, damage cell structures, affect cell metabolism, and inhibit protein synthesis to exert an antibacterial effect.ConclusionsWe concluded that the mechanism of action of the PAA against strain T-37 might be described as PAA exerting antibacterial activity by affecting cell metabolism, inhibiting protein synthesis, and destroying cell membrane integrity and cell ultrastructure. Therefore, PAA has a promising application prospect in the prevention and treatment of root cancer disease caused by A. tumefaciens.

【 授权许可】

CC BY