Table 1. Bacterial strains and plasmids used in this study.

Strain or plasmid	Genotype and/or relevant characteristics	Reference or source
P. aeruginosa
PAO1 (ATCC15692)	Prototroph	American type culture collection
PA14	Prototroph	[20]
TR1	Prototroph; cystic fibrosis isolate	[21]
PAO1 araCPBAD tolB	PAO1 with an arabinose-inducible additional copy of tolB inserted into the attB neutral site	This work
PAO1 ΔtolB araCPBAD tolB	PAO1 araCPBAD tolB deleted of the endogenous copy of tolB	This work
PA14 araCPBAD tolB	PA14 with an arabinose-inducible additional copy of tolB inserted into the attB neutral site	This work
PA14 ΔtolB araCPBAD tolB	PA14 araCPBAD tolB deleted of the endogenous copy of tolB	This work
TR1 araCPBAD tolB	TR1 with an arabinose-inducible additional copy of tolB inserted into the attB neutral site	This work
TR1 ΔtolB araCPBAD tolB	TR1 araCPBAD tolB deleted of the endogenous copy of tolB	This work
E. coli
S17.1λpir	thi pro hsdR hsdM+ recA RP4-2-Tc::Mu-Km::Tn7 λpir, GmR	[22]
DH5αF'	recA1 endA1 hsdR17 supE44 thi-1 gyrA96 relA1 Δ(lacZYA-argF)U169[φ80 dlacZΔM15], NalR	[23]
Plasmid
pBluescript-II KS+	Cloning vector; ColE1 replicon; ApR	Stratagene
pDM4	Suicide vector; sacBR, oriR6K; CmR	[23]
pDM4ΔtolB	pDM4 derivative for tolB in-frame deletion; CmR	This work
pBEM9	Vector carrying the araCPBAD regulatory region with an altered RBS for stringent arabinose-dependent control in P. aeruginosa; ApR	[24]
pBEM9-tolB	pBEM9 derivative carrying the tolB coding sequence cloned by HindIII/EcoRI digestion downstream of the araCPBAD regulatory region	This work
mini-CTX1	Self-proficient integration vector with tet, Ω-FRT-attP-MCS, ori, int, and oriT; TcR	[26]
mini-CTX1-araCPBAD tolB	mini-CTX1 derivative carrying the araCPBAD tolB from pBEM9 cloned by XhoI/EcoRI digestion	This work