Quorum Sensing in Agrobacterium tumefaciens Using N-oxo-Acyl-homoserine Lactone Chemical Signal

 

Anna Szenthe and William J. Page

Tested Studies in Laboratory Teaching, 2003, Volume 24

Abstract

Bacteria utilize a low molecular weight chemical belonging to the N-oxo-acylhomoserine lactone (HSL) family for communication by quorum sensing. In this exercise we observe HSL production in wild type Agrobacterium tumefaciens. with the aid of a reporter strain (a modified A. tumefaciens strain with a lacZ reporter gene). The reporter strain produces ß-galactosidase in response to exogenous HSL generated by the test organism. This production is first measured qualitatively by observing X-gal cleavage as indicated by the appearance of blue color in a soft agar overlay, and then quantitatively by employing the lactose analog ONPG (ortho-nitrophenyl-galactopyranoside) in a spectrophotometric assay.

Keywords:  Agrobacterium tumefaciens, crown gall disease, natural genetic engineering of plants, TraR protein, Ti plasmid, octopine catabolism, community oriented growth pattern, N-oxo-Acyl-homoserine lactone, autoinducer, lac Z reporter gene, beta galactosidase, ONPG

Louisiana State University (2002)