A bioluminescent whole-cell reporter for detection of 2,4-dichlorophenoxyacetic acid and 2,4-dichlorophenol in soil

A bioreporter was made containing a tfdRP(DII)-luxCDABE: fusion in a modifi ed mini-Tn5 construct. When it was introduced into the chromosome of Ralsto nia eutropha JMP134, the resulting strain, JMP134-32, produced a sensitive bioluminescent response to 2,4-dichlorophenoxyacetic acid (2,4-D) at concen trations of 2.0 mu M to 5.0 mM. This response was linear (R-2 = 0.9825) in the range of 2.0 mu M to 1.1 x 10(2) mu M. Saturation occurred at higher co ncentrations, with maximal bioluminescence occurring in the presence of app roximately 1.2 mM 2,4-D. A sensitive response was also recorded in the pres ence of 2,4-dichlorophenol at concentrations below 1.1 x 10(2) mu M; howeve r, only a limited bioluminescent response was recorded in the presence of 3 -chlorobenzoic acid at concentrations below 1.0 mM. A significant biolumine scent response was also recorded when strain JMP134-32 was incubated with s oils containing aged 2,4-D residues.