Fig. 2.

The expression of lqqP in Pseudomonas fluorescens 2P24 remarkably inhibits the production of AHL. (A) Co-IP reveals a list of potential PcoI-binding proteins from L. enzymogenes OH11; (B-C) The production of AHL in 2P24 carrying each PcoI-binding protein gene shown in Fig. 2A was determined by the AHL bioassay strain JZA1 (B) and the AHL quantification indicated by β-galactosidase assay (C); (D) Biofilm formation of 2P24 carrying lqqP and its variant gene lqqP^C78Y. ΔpcoI, the pcoI mutant of P. fluorescens 2P24 lacking the ability to produce AHL; gfp, a negative control; (E-F) Effect of LqqP truncations (E) on blocking AHL production in 2P24 (F). Coding sequences of LqqP truncations were separately cloned into a broad-host vector, pBBR1-MCS5 and transformed into 2P24, followed by AHL plate detection (up panel) and quantification (down panel) as described in panels B-C. In panels B, C, D, F, average data from three experiments are presented, ± SD. ***P < 0.0001 relative to 2P24 or 2P24 expressing gfp. “ns” stands for not statistically significant.