Chromosomally located gene fusions constructed in Acinetobacter sp. ADP1 for the detection of salicylate

Abstract

Acinetobacter sp. ADP1 is a common soil-associated bacterium with high natural competency, allowing it to efficiently integrate foreign DNA fragments into its chromosome. This property was exploited to engineer salicylate-inducible luxCDABE and green fluorescent protein (GFP) variants of Acinetobacter sp. ADP1. Specifically, Acinetobacter sp. ADPWH_lux displayed the higher sensitivity when comparing the two variants (minimum detection c. 0.5-1 microM salicylate) and a faster turnover of the lux marker gene, making it suitable for whole-cell luminescence assays of salicylate concentration. In contrast, the longer maturation and turnover times of the GFP protein make the Acinetobacter sp. ADPWH_gfp variant more suited to applications involving whole-cell imaging of the presence of salicylate. The sensitivity of the luxCDABE variant was demonstrated by assaying salicylate production in naphthalene-degrading cultures. Assays using ADPWH_lux specifically mapped the kinetics of salicylate production from naphthalene and were similar to that observed by high-performance liquid chromatography (HPLC) data. However, ADPWH_lux exhibited the higher sensitivity, when compared with HPLC, for detecting salicylate production during the first 24 h of naphthalene metabolism. These data demonstrate that the engineered Acinetobacter variants have significant potential for salicylate detection strategies in laboratory and field studies, especially in scenarios where genetic stability of the construct is required for in situ monitoring.

Salicylic acid mediates the reduced growth of lignin down-regulated plants

“…SA levels were determined by using the biosensor organism Acinetobacter sp. ADPWH_lux as described previously (36,37) and in SI Materials and Methods.…”

Bacterial recombination promotes the evolution of multi-drug-resistance in functionally diverse populations

“…To verify the recombination rate of our constructed strains, we compared the transformation capacity of Rec (2) to that of an ADPWH_lux_DsalR mutant that had the selective salR deletion marker, but without the knockout of recA [35]. Transformation of both mutants was attempted by mixing cells with PCR products of intact salR fragments using ADP1 colony as DNA template (PCR primers are listed in electronic supplementary material, table S2).…”

Acinetobacter baylyi ADP1: Transforming the choice of model organism

“…For example, salicylic acid is an important plant chemical that signals stress or infection. In strain ADPWH_lux, luminescence genes from Photorhabdus luminescens are under control of the chromosomal salA promoter and allow quantification of free salicylic acid with astounding accuracy and sensitivity (35)(36)(37). In addition, b-glucosidase can be used to treat samples containing glucose-conjugated salicylic acid, an inert storage reservoir.…”