Related Experiment Video
Updated: Jul 31, 2026

Biosensor-based High Throughput Biopanning and Bioinformatics Analysis Strategy for the Global Validation of Drug-protein Interactions
Published on: December 1, 2020
Protocol: a simple method for biosensor visualization of bacterial quorum sensing and quorum quenching interaction on
1Department of Plant and Soil Sciences, University of Delaware, 311 AP Biopharma, 590 Avenue 1743, Newark, DE, 19713, USA. amandaro@udel.edu.
Background:
Defining interactions of bacteria in the rhizosphere (encompassing the area near and on the plant root) is important to understand how they affect plant health. Some rhizosphere bacteria, including plant growth promoting rhizobacteria (PGPR) engage in the intraspecies communication known as quorum sensing (QS). Many species of Gram-negative bacteria use extracellular autoinducer signal molecules called N-acyl homoserine lactones (AHLs) for QS. Other rhizobacteria species, including PGPRs, can interfere with or disrupt QS through quorum quenching (QQ). Current AHL biosensor assays used for screening and identifying QS and QQ bacteria interactions fail to account for the role of the plant root.
Methods:
Medicago spp. seedlings germinated on Lullien agar were transferred to soft-agar plates containing the broad-range AHL biosensor Agrobacterium tumefaciens KYC55 and X-gal substrate. Cultures of QS and QQ bacteria as well as pure AHLs and a QQ enzyme were applied to the plant roots and incubated for 3 days.
Results:
We show that this expanded use of an AHL biosensor successfully allowed for visualization of QS/QQ interactions localized at the plant root. KYC55 detected pure AHLs as well as AHLs from live bacteria cultures grown directly on the media. We also showed clear detection of QQ interactions occurring in the presence of the plant root.
Conclusions:
Our novel tri-trophic system using an AHL biosensor is useful to study QS interspecies interactions in the rhizosphere.
Related Concept Videos
Bacterial Signaling
Gene Regulation in Microbial Communities: Quorum Sensing
Microbial Biosensors

