Quorum sensing activity of Enterobacter asburiae isolated from lettuce leaves.

Yin Lau,Jian Chen,Joanita Sulaiman,Wai-Fong Yin,Kok-Gan Chan

doi:10.3390/s131014189

Abstract

Bacterial communication or quorum sensing (QS) is achieved via sensing of QS signaling molecules consisting of oligopeptides in Gram-positive bacteria and N-acyl homoserine lactones (AHL) in most Gram-negative bacteria. In this study, Enterobacteriaceae isolates from Batavia lettuce were screened for AHL production. Enterobacter asburiae, identified by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) was found to produce short chain AHLs. High resolution triple quadrupole liquid chromatography mass spectrometry (LC/MS) analysis of the E. asburiae spent supernatant confirmed the production of N-butanoyl homoserine lactone (C4-HSL) and N–hexanoyl homoserine lactone (C6-HSL). To the best of our knowledge, this is the first report of AHL production by E. asburiae.

Highlights

Quorum sensing (QS) refers to the capabilities of microorganisms to communicate via secreted signaling molecules called autoinducers which contribute to the regulation of gene expression in response to surrounding bacterial population density [1]
Enterobacter asburiae is a Gram-negative bacillus belonging to the Enterobacteriaceae family that has been isolated from soil, water and food products [11,12]
We aimed to identify the acyl homoserine lactones (AHL)(s) produced by the isolated Gram-negative bacteria E. asburiae from the Enterobacteriaceae family, obtained from Batavia lettuce

Summary

Introduction

Quorum sensing (QS) refers to the capabilities of microorganisms to communicate via secreted signaling molecules called autoinducers which contribute to the regulation of gene expression in response to surrounding bacterial population density [1]. Gram-negative bacteria employ AHL as QS signals in their communication circuits to regulate a diverse array of physiological activities These processes include symbiosis, virulence, competence, conjugation, antibiotic production, motility, sporulation, and biofilm formation [2]. Enterobacter asburiae is a Gram-negative bacillus belonging to the Enterobacteriaceae family that has been isolated from soil, water and food products [11,12]. It is termed an epiphytic bacterium [13], which are generally described as microorganisms that live on plant surfaces and can either be favorable or harmful to the plant they reside on [14]. We aimed to identify the AHL(s) produced by the isolated Gram-negative bacteria E. asburiae from the Enterobacteriaceae family, obtained from Batavia lettuce

Sample Collection and Processing

Isolation and Identification of Bacterial Strains

AHL Detection of Bacteria Isolates

AHL Extraction and Measurement of Bioluminescence

Identification of Bacterial Isolates from Batavia Lettuce