Pseudomonas syringae strains translocate large and distinct collections of effector proteins into plant cells via the type III secretion system (T3SS). Mutations in T3SS-encoding hrp genes are unable to elicit the hypersensitive response or pathogenesis in nonhost and host plants, respectively. Mutations in individual effectors lack strong phenotypes, which has impeded their discovery. P. syrin...

The phytopathogenic bacterium Pseudomonas syringae pv. glycinea infects soybean plants and causes bacterial blight. In addition to P. syringae, the human pathogen Pseudomonas aeruginosa and the soil bacterium Azotobacter vinelandii produce the exopolysaccharide alginate, a copolymer of d-mannuronic and l-guluronic acids. Alginate production in P. syringae has been associated with increased fitn...

Resistance of tomato plants to the bacterial pathogen Pseudomonas syringae pv. tomato race 0 is controlled by the locus Pto. A bacterial avirulence gene was cloned by constructing a cosmid library from an avirulent P. syringae pv. tomato race, conjugating the recombinants into a strain of P. syringae pv. maculicola virulent on a tomato cultivar containing Pto, and screening for those clones tha...

ABSTRACT Thirty-eight bacterial strains isolated from hazelnut (Corylus avellana) cv. Tonda Gentile delle Langhe showing a twig dieback in Piedmont and Sardinia, Italy, were studied by a polyphasic approach. All strains were assessed by fatty acids analysis and repetitive sequence-based polymerase chain reaction (PCR) fingerprinting using BOX and ERIC primer sets. Representative strains also we...

AvrPtoB is a type III effector protein from Pseudomonas syringae pv. tomato that physically interacts with the tomato Pto kinase and, depending on the host genotype, either elicits or suppresses programmed cell death associated with plant immunity. We reported previously that avrPtoB-related sequences are present in diverse gram-negative phytopathogenic bacteria. Here we describe characterizati...

Many plant pathogens suppress antimicrobial defenses using virulence factors that modulate endogenous host defenses. The Pseudomonas syringae phytotoxin coronatine (COR) is believed to promote virulence by acting as a jasmonate analog, because COR-insensitive 1 (coil) Arabidopsis thaliana and tomato mutants are impaired in jasmonate signaling and exhibit reduced susceptibility to P. syringae. T...

The species Pseudomonas syringae encompasses plant pathogens with differing host specificities and corresponding pathovar designations. P. syringae requires the Hrp (type III protein secretion) system, encoded by a 25-kb cluster of hrp and hrc genes, in order to elicit the hypersensitive response (HR) in nonhosts or to be pathogenic in hosts. DNA sequence analysis of the hrpC and hrpRS operons ...

as a diagnostic probe for P. syringae pv. tomato. In a survey of 75 plant-associated bacteria, pTPR1 hybridized exclusively to those strains that produced coronatine. The detection limit for this probe, which was labeled with the Chemiprobe nonradioactive reporter system, was approximately 4 x 103 CFU of lesion bacteria. During the 1989 growing season, a total of 258 leaf and fruit lesions from...

The host-specific plant pathogen Pseudomonas syringae elicits the hypersensitive response (HR) in nonhost plants and secretes the HrpZ harpin in culture via the Hrp (type III) secretion system. Previous genetic evidence suggested the existence of another harpin gene in the P. syringae genome. hrpW was found in a region adjacent to the hrp cluster in P. syringae pv. tomato DC3000. hrpW encodes a...

The molecular characteristics of the ethylene-forming enzymes of strains of Pseudomonas syringae were tested. The ethylene-producing activities of the nine strains as measured in vivo and in vitro were similar, except for that of P. syringae pv. mori M5. A polyclonal antibody and a DNA probe for the ethylene-forming enzyme from P. syringae pv. phaseolicola PK2 were prepared to investigate homol...