Regulation of Biosurfactant Production by Quorum Sensing in Pseudomonas fluorescens 5064, the Cause of Broccoli Head Rot Disease

摘要: iii Regulation of biosurfactant production by quorum sensing in Pseudomonas fluorescens 5064, the cause broccoli head rot disease Broccoli is a destructive found most areas. The main pathogen bacterium fluorescens. P. which was first isolated from an infected SE Scotland, produces biosurfactants that are important for bacterial establishment on plant surface prior to causing broccoli. Preliminary experiments performed this study showed 5064 cell density dependent, typical characteristic mechanism. Quorum communication mechanism, controls number key processes growth, reproduction and virulence via signalling molecules (quorum signal) many gram-negative bacteria. One aim determine if controlled sensing. To do this, 35 surfactant-minus Tn5 mutants were screened their abilities produce signal. Six these biosurfactant-deficient large reduction signal production. In one mutant 6423, contains single insertion, almost eliminated. Addition signal, either synthetic or extracted wild type able restore 6423. This strongly suggests regulates 5064. Attempts made clone sequence disrupted gene but identity remains inconclusive. identified High Pressure Liquid Chromatography Mass Spectrometry as N-3-