TY - JOUR
T1 - Complete nucleotide sequence and analysis of pPSR1 (72,601 bp), a pPT23A-family plasmid from Pseudomonas syringae pv. syringae A2
AU - Sundin, G. W.
AU - Mayfield, C. T.
AU - Zhao, Y.
AU - Gunasekera, T. S.
AU - Foster, G. L.
AU - Ullrich, M. S.
N1 - Funding Information:
Acknowledgements We thank Gayle McGhee for assistance with Fig. 1, and two anonymous reviewers, whose comments significantly enhanced the manuscript. This work was supported by competitive grants from the United States Department of Agriculture and the Texas Higher Education Coordinating Board Advanced Research Program, and by the Agricultural Experiment Stations of Texas and Michigan
PY - 2004/1
Y1 - 2004/1
N2 - Plasmid pPSR1 is a conjugative plasmid originally isolated from Pseudomonas syringae pv. syringae A2, and is a member of the recently described pPT23A plasmid family. We have determined the complete sequence of pPSR1 and found the plasmid to be 72,601 bp in length, encoding 55 ORFs. Putative functions were assigned to 49 ORFs; of these, 24 (49.0%) are involved in plasmid replication, maintenance or conjugation, 17 (34.7%) have roles in virulence or ecological fitness, and eight (16.3%) encode transposase functions as part of mobile elements. pPSR1 carries the effector gene orf34, the mutagenic DNA repair operon rulAB which confers tolerance to ultraviolet radiation, and two genes for methyl-accepting chemotaxis proteins, one of which was located within the novel transposon Tn5395. The streptomycin resistance transposon Tn5393a, which carries a strA-strB determinant, was found inserted immediately downstream of the pPSR1 repA gene. Functional analysis of the replication region of pPSR1 indicated that the repA gene and flanking upstream and downstream sequences are required for autonomous replication in P. syringae. Hybridization analyses of the distribution of 11 of the pPSR1 ORFs indicated that many of the ecologically important ORFs were confined to the pathovar P. syringae pv. syringae - either to strains from the local population from which pPSR1 was originally isolated, or strains from a worldwide collection. Conjugative transfer genes and a gene encoding a transcriptional regulator were more widely distributed among several P. syringae pathovars. The sequence analysis of pPSR1 suggests that pPT23A-family plasmids evolve by accumulating genes that are important for host-pathogen interactions or growth on plant hosts, which are incorporated onto a conserved backbone encoding conjugation and stability determinants.
AB - Plasmid pPSR1 is a conjugative plasmid originally isolated from Pseudomonas syringae pv. syringae A2, and is a member of the recently described pPT23A plasmid family. We have determined the complete sequence of pPSR1 and found the plasmid to be 72,601 bp in length, encoding 55 ORFs. Putative functions were assigned to 49 ORFs; of these, 24 (49.0%) are involved in plasmid replication, maintenance or conjugation, 17 (34.7%) have roles in virulence or ecological fitness, and eight (16.3%) encode transposase functions as part of mobile elements. pPSR1 carries the effector gene orf34, the mutagenic DNA repair operon rulAB which confers tolerance to ultraviolet radiation, and two genes for methyl-accepting chemotaxis proteins, one of which was located within the novel transposon Tn5395. The streptomycin resistance transposon Tn5393a, which carries a strA-strB determinant, was found inserted immediately downstream of the pPSR1 repA gene. Functional analysis of the replication region of pPSR1 indicated that the repA gene and flanking upstream and downstream sequences are required for autonomous replication in P. syringae. Hybridization analyses of the distribution of 11 of the pPSR1 ORFs indicated that many of the ecologically important ORFs were confined to the pathovar P. syringae pv. syringae - either to strains from the local population from which pPSR1 was originally isolated, or strains from a worldwide collection. Conjugative transfer genes and a gene encoding a transcriptional regulator were more widely distributed among several P. syringae pathovars. The sequence analysis of pPSR1 suggests that pPT23A-family plasmids evolve by accumulating genes that are important for host-pathogen interactions or growth on plant hosts, which are incorporated onto a conserved backbone encoding conjugation and stability determinants.
KW - Effector proteins
KW - Epiphytic fitness
KW - Phyllosphere
KW - Virulence plasmids
KW - virB operon
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U2 - 10.1007/s00438-003-0945-9
DO - 10.1007/s00438-003-0945-9
M3 - Article
C2 - 14634868
AN - SCOPUS:1042288628
SN - 1617-4615
VL - 270
SP - 462
EP - 476
JO - Molecular Genetics and Genomics
JF - Molecular Genetics and Genomics
IS - 6
ER -