Table 2.

Overview of localization, relative G+C contents, and lengths of pathogenicity islands which encode type III secretion system gene clusters

OrganismLocationRelative G+C content of type III gene cluster (%) (reference)Medium relative G+C content of rest of genome (%) (reference)Length (kb) (reference)
Yersinia spp.70-kb plasmid4446–50ca. 20
P. aeruginosa Chromosomal, 55 min (493)67.5 (491)69 (491)?
S. typhimurium SPI-1Chromosomal centisome 6342–47 (63)52 (332)ca. 40 (312)
S. typhimurium SPI-2Chromosomal centisome 30.742–45 (194,332)52 (332)?
S. flexneri 220-kb plasmid34 (332)51 (332)ca. 31
EPECChromosomal, centisome 8238.4 (102)51 (332)35.5
Chlamydiaspp.?40 (211)41–44% (211)?
P. syringae Chromosomal (365)ca. 61a ?22 (365)
E. amylovora Chromosomalca. 58a ?ca. 25 (470)
R. solanacearum Megaplasmid69.1a ?ca. 27 (448)
X. campestris Chromosomal64.6a ?ca. 25 (61) 
Rhizobium spp.sym plasmid (139)56 (139)58.5% for the sym plasmid (139)17.7 (139)
  • a Determined from published sequences.