title: Antagonistic mechanisms of endophytic Pseudomonas fluorescens against Athelia rolfsii.
abstract: OBJECTIVE
  To explore specific mechanisms of endophytic Pseudomonas fluorescens antagonizing Athelia rolfsii, causing southern blight of Atractylodes lancea and to evaluate the potential of this Ps. fluorescens strain to control southern blight.
  
  
  RESULTS
  Endophytic Ps. fluorescens strain ALEB 7B isolated from A. lancea can significantly inhibit the growth of A. rolfsii strain SY4. Pre-inoculating A. lancea seedlings with Ps. fluorescens ALEB 7B reduces the southern blight morbidity rate significantly. In situ observation using scanning electron microscopy shows Ps. fluorescens ALEB 7B colonizing the plant cells. Volatile organic compounds (VOCs) from Ps. fluorescens ALEB 7B can kill A. rolfsii SY4 and dimethyl disulphide (DMDS) plays a major role. 2-Piperidinone is a unique substance having antifungal activity in dichloromethane extracts of bacterial cell-free culture filtrates. Other antagonistic mechanisms include ecological niche occupation, antibiotic production and lytic exoenzymes secretion.
  
  
  CONCLUSIONS
  Specific antagonistic mechanisms of Ps. fluorescens ALEB 7B on A. rolfsii SY4 were detailed, including release of DMDS, production of 2-piperidone, secretion of antibiotics and lytic exoenzymes and competition for spaces and nutrients.
  
  
  CONCLUSIONS
  This work firstly reports the significant inhibition of VOCs released by Ps. fluorescens on the growth of A. rolfsii. 2-Piperidinone is firstly found synthesized by Ps. fluorescens, having antifungal activity. This work provides an antagonistic bacterium with practical convenience and ecologically amity, which has potential for control to A. rolfsii in vitro.
authors: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences, Nanjing Normal University, Jiangsu Province, Nanjing, China.
authors: J Y
authors: JY
authors: Zhou
authors: X Y
authors: XY
authors: Zhao
authors: C C
authors: CC
authors: Dai
mesh_terms: D000898:Antibiosis; D000935:Antifungal Agents / Q000494:pharmacology; D031174:Atractylodes / Q000382:microbiology*; D001487:Basidiomycota / Q000187:drug effects / Q000254:growth & development*; D064347:Microscopy, Electrochemical, Scanning; D010881:Piperidones / Q000494:pharmacology; D011551:Pseudomonas fluorescens / Q000737:chemistry* / Q000302:isolation & purification / Q000648:ultrastructure; D055549:Volatile Organic Compounds / Q000032:analysis
chemical_list: D000935:Antifungal Agents; D010881:Piperidones; D055549:Volatile Organic Compounds; C043384:2-piperidone
keywords: 2-piperidinone; Atractylodes lancea; Pseudomonas fluorescens; endophytic bacterium; southern blight; specific mechanism; volatile organic compound