Identification of a pathogenicity island, which contains genes for virulence and avirulence, on a large native plasmid in the bean pathogen Pseudomonas syringae pathovar phaseolicola
Fecha
1999Autor
Versión
Acceso abierto / Sarbide irekia
Tipo
Artículo / Artikulua
Versión
Versión publicada / Argitaratu den bertsioa
Impacto
|
10.1073/pnas.96.19.10875
Resumen
The 154-kb plasmid was cured from race 7
strain 1449B of the phytopathogen Pseudomonas syringae pv.
phaseolicola (Pph). Cured strains lost virulence toward bean,
causing the hypersensitive reaction in previously susceptible
cultivars. Restoration of virulence was achieved by complementation
with cosmid clones spanning a 30-kb region of the plasmid
that contained previously identified avirulence ( ...
[++]
The 154-kb plasmid was cured from race 7
strain 1449B of the phytopathogen Pseudomonas syringae pv.
phaseolicola (Pph). Cured strains lost virulence toward bean,
causing the hypersensitive reaction in previously susceptible
cultivars. Restoration of virulence was achieved by complementation
with cosmid clones spanning a 30-kb region of the plasmid
that contained previously identified avirulence (avr) genes avrD,
avrPphC, and avrPphF. Single transposon insertions at multiple
sites (including one located in avrPphF) abolished restoration of
virulence by genomic clones. Sequencing 11 kb of the complementing
region identified three potential virulence (vir) genes
that were predicted to encode hydrophilic proteins and shared
the hrp-box promoter motif indicating regulation by HrpL. One
gene achieved partial restoration of virulence when cloned on its
own and therefore was designated virPphA as the first (A) gene
from Pph to be identified for virulence function. In soybean,
virPphA acted as an avr gene controlling expression of a rapid
cultivar-specific hypersensitive reaction. Sequencing also revealed
the presence of homologs of the insertion sequence IS100
from Yersinia and transposase Tn501 from P. aeruginosa. The
proximity of several avr and vir genes together with mobile
elements, as well as G1C content significantly lower than that
expected for P. syringae, indicates that we have located a plasmidborne
pathogenicity island equivalent to those found in mammalian
pathogens. [--]
Materias
Plant disease resistance,
Hypersensitive reaction,
Signal transduction
Editor
National Academy of Sciences
Publicado en
PNAS September 14, 1999 96 (19) 10875-10880
Departamento
Universidad Pública de Navarra. Departamento de Producción Agraria /
Nafarroako Unibertsitate Publikoa. Nekazaritza Ekoizpena Saila
Versión del editor
Entidades Financiadoras
We acknowledge support from the Biotechnology and
Biological Sciences Research Council, European Community Grant
BIO-CT97-2244, Comisión Interministerial de Ciencia y Tecnología
Grant BIO97–0598, and the British Council Acciones Integradas
program.