Summary: JOURNAL OF BACTERIOLOGY, Jan. 2005, p. 649663 Vol. 187, No. 2
0021-9193/05/$08.00 0 doi:10.1128/JB.187.2.649663.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.
The hrpK Operon of Pseudomonas syringae pv. tomato DC3000
Encodes Two Proteins Secreted by the Type III (Hrp)
Protein Secretion System: HopB1 and HrpK,
a Putative Type III Translocator
Karin van Dijk,1
and James R. Alfano1
Plant Science Initiative and Department of Plant Pathology1
and School of Biological Sciences,2
University of Nebraska, Lincoln, Nebraska
Received 29 July 2004/Accepted 4 October 2004
Pseudomonas syringae is a gram-negative bacterial plant pathogen that is dependent on a type III protein
secretion system (TTSS) and the effector proteins it translocates into plant cells for pathogenicity. The P.
syringae TTSS is encoded by hrp-hrc genes that reside in a central region of a pathogenicity island (Pai).
Flanking one side of this Pai is the exchangeable effector locus (EEL). We characterized the transcriptional
expression of the open reading frames (ORFs) within the EEL of P. syringae pv. tomato DC3000. One of these