Open AccessEvidence for the mobility of an avirulence gene, avrPpiA1 , between the chromosome and plasmids of races of Pseudomonas syringae pv. pisi
Author(s) -
Arnold Dawn Louise,
Jackson Robert Wilson,
Vivian Alan
Publication year - 2000
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1046/j.1364-3703.2000.00019.x
Subject(s) - biology , pseudomonas syringae , orfs , genetics , gene , plasmid , transposase , inverted repeat , mobile genetic elements , horizontal gene transfer , insertion sequence , chromosome , open reading frame , transposable element , genome , peptide sequence
An 8.5‐kb DNA fragment containing the avirulence gene avrPpiA1 is present in the chromosome of race 2 but not present in race 4B of Pseudomonas syringae pv. pisi . The likely acquisition of avrPpiA1 in race 2 at some time in the past was indicated by the presence of direct repeat sequences at the boundaries of the 8.5‐kb region, which was amplified by polymerase chain reaction (PCR), cloned and sequenced. The sequence analysis of the 8.5‐kb fragment revealed the presence of rulAB genes, which are usually associated with plasmids. The rulB gene had been disrupted by a 4.3‐kb length of DNA, which included avrPpiA1 and open reading frames (ORFs) with similarity to bacteriophage and transposase genes. Inverted repeats flanked the 4.3‐kb region reinforcing the possibility that a further insertion had occurred in this region. The results presented here provide evidence for the horizontal transfer of an avirulence gene and suggest that this region may be a hotspot for recombination with the chromosome.