TABLE 1.

Bacterial strains and plasmids used

Strain or plasmid	Description	Source or reference
Strains
E. coli DH5α	F− φ80dlacZΔM15 Δ(lacZYA-argF)U169 endA1 recA1 hsdR17(rK− rM+) deoR thi-1 supE44 λ−gyrA96 relA1	Life Technologies, Inc. (Gaithersburg, Md.)
Erwinia amylovora
Ea273	Wild type	S. V. Beer
Ea273-K178	Hrp secretion mutant; Tn10 mini-Km insertion in hrpJ operon	Z.-M. Wei (34)
Ea273dspEΔ1521	Nonpolar dspE mutant; 1,521-bp in-frame deletion in 3′ half of dspE	4
Plasmids
pCPP50	pINIII113-A2-based expression vector; Apr	3
pCPP1244	3.1-kb HpaI-BamHI clone containing 5′ half of dspE in pCPP50	4
pCPP1259	7.7-kb HpaI-HindIII clone containing dspE and dspF in pCPP50	4