title: Comparative analysis of the Hrp pathogenicity island of Rubus- and Spiraeoideae-infecting Erwinia amylovora strains identifies the IT region as a remnant of an integrative conjugative element.
abstract: The Hrp pathogenicity island (hrpPAI) of Erwinia amylovora not only encodes a type III secretion system (T3SS) and other genes required for pathogenesis on host plants, but also includes the so-called island transfer (IT) region, a region that originates from an integrative conjugative element (ICE). Comparative genomic analysis of the IT regions of two Spiraeoideae- and three Rubus-infecting strains revealed that the regions in Spiraeoideae-infecting strains were syntenic and highly conserved in length and genetic information, but that the IT regions of the Rubus-infecting strains varied in gene content and length, showing a mosaic structure. None of the ICEs in E. amylovora strains were complete, as conserved ICE genes and the left border were missing, probably due to reductive genome evolution. Comparison of the hrpPAI region of E. amylovora strains to syntenic regions from other Erwinia spp. indicates that the hrpPAI and the IT regions are the result of several insertion and deletion events that have occurred within the ICE. It also suggests that the T3SS was present in a common ancestor of the pathoadapted Erwinia spp. and that insertion and deletion events in the IT region occurred during speciation.
authors.affiliation: Cooperative Research Centre for National Plant Biosecurity, 621 Burwood Hwy, Knoxfield, VIC 3180, Australia.
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Mann
authors.forename: Jochen
authors.initials: J
authors.lastname: Blom
authors.forename: Andreas
authors.initials: A
authors.lastname: Bühlmann
authors.forename: Kim M
authors.initials: KM
authors.lastname: Plummer
authors.forename: Steven V
authors.initials: SV
authors.lastname: Beer
authors.forename: Joanne E
authors.initials: JE
authors.lastname: Luck
authors.forename: Alexander
authors.initials: A
authors.lastname: Goesmann
authors.forename: Jürg E
authors.initials: JE
authors.lastname: Frey
authors.forename: Brendan C
authors.initials: BC
authors.lastname: Rodoni
authors.forename: Brion
authors.initials: B
authors.lastname: Duffy
authors.forename: Theo H M
authors.initials: TH
authors.lastname: Smits
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D003227:Conjugation, Genetic; D027825:Crataegus / Q000382:microbiology*; D004268:DNA-Binding Proteins / Q000235:genetics*; D044084:Erwinia amylovora / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity; D015964:Gene Expression Regulation, Bacterial; D044404:Genomic Islands / Q000235:genetics*; D020071:Interspersed Repetitive Sequences / Q000235:genetics*; D010935:Plant Diseases / Q000382:microbiology; D027824:Rosaceae / Q000382:microbiology*; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C421032:HrpY protein, Erwinia amylovora