Laminaria japonica Extract, an Inhibitor of Clavibater michiganense Subsp. Sepedonicum

• Published in: PloS one Vol. 9; no. 4; p. e94329
• Main Authors: Cai, Jin, Feng, Jia, Xie, Shulian, Wang, Feipeng, Xu, Qiufeng
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 08.04.2014; Public Library of Science (PLoS)
• Subjects: Actinomycetales - drug effects; Actinomycetales - metabolism; Actinomycetales - ultrastructure; Anti-Bacterial Agents - pharmacology; Bacterial Proteins - metabolism; Biology and Life Sciences; Calcium - metabolism; Catalase - metabolism; Cell Membrane - drug effects; Cell Wall - drug effects; Chemical Fractionation; Cytosol - metabolism; DNA Replication - drug effects; Laminaria - chemistry; Microbial Sensitivity Tests; Plant Extracts - pharmacology; Reactive Oxygen Species - metabolism; Superoxide Dismutase - metabolism
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0094329

Bacterial ring rot of potato is one of the most serious potato plant and tuber diseases. Laminaria japonica extract was investigated for its antimicrobial activity against Clavibater michiganense subsp. sepedonicum (Spieckermann & Kotthoff) Davis et al., the causative agent of bacterial ring rot of potato. The results showed that the optimum extraction conditions of antimicrobial substances from L. japonica were an extraction temperature of 80°C, an extraction time of 12 h, and a solid to liquid ratio of 1∶25. Active compounds of L. japonica were isolated by solvent partition, thin layer chromatography (TLC) and column chromatography. All nineteen fractionations had antimicrobial activities against C. michiganense subsp. sepedonicum, while Fractionation three (Fr.3) had the highest (P<0.05) antimicrobial activity. Chemical composition analysis identified a total of 26 components in Fr.3. The main constituents of Fr.3 were alkanes (80.97%), esters (5.24%), acids (4.87%) and alcohols (2.21%). Antimicrobial activity of Fr.3 against C. michiganense subsp. sepedonicum could be attributed to its ability to damage the cell wall and cell membrane, induce the production of reactive oxygen species (ROS), increase cytosolic Ca2+ concentration, inhibit the glycolytic pathway (EMP) and tricarboxylic acid (TCA) cycle, inhibit protein and nucleic acid synthesis, and disrupt the normal cycle of DNA replication. These findings indicate that L. japonica extracts have potential for inhibiting C. michiganense subsp. sepedonicum.