The plant pathogen Pseudomonas syringae may cope with osmotic stress on plants, in part, by importing osmoprotective compounds. In this study, we found that P. syringae pv. tomato strain DC3000 was distinct from most bacterial species in deriving greater osmoprotection from exogenous choline than from glycine betaine. This superior osmoprotection was correlated with a higher capacity for uptake...

Many strains of Pseudomonas syringae pv. syringae produce one of four classes of small cyclic lipodepsinonapeptides: syringomycins, syringostatins, syringotoxins, or pseudomycins. These metabolites are phytotoxic and growth inhibitory against a broad spectrum of fungi. Their production is dependent upon the expression of conserved biosynthesis and export genes syrB and syrD, respectively. PCR a...

Two types of necrosis-inducing lipodepsipeptide toxins, called syringomycin and syringopeptin, are major virulence factors of Pseudomonas syringae pv. syringae strain B301D. A previous study showed that a locus, called syrA, was required for both syringomycin production and plant pathogenicity, and the syrA locus was speculated to encode a regulator of toxin production. In this study, sequence ...

The ability of Pseudomonas syringae pv. phaseolicola to cause halo blight of bean is dependent on its ability to translocate effector proteins into host cells via the hypersensitive response and pathogenicity (Hrp) type III secretion system (T3SS). To identify genes encoding type III effectors and other potential virulence factors that are regulated by the HrpL alternative sigma factor, we used...

The plant pathogen Pseudomonas syringae may cope with osmotic stress on plants, in part, by importing osmoprotective compounds. In this study, we found that P. syringae pv. tomato strain DC3000 was distinct from most bacterial species in deriving greater osmoprotection from exogenous choline than from glycine betaine. This superior osmoprotection was correlated with a higher capacity for uptake...

Production of the phytotoxins syringomycin and syringopeptin by Pseudomonas syringae pv. syringae is controlled by the regulatory genes salA and syrF. Analysis with 70-mer oligonucleotide microarrays established that the syr-syp genes responsible for synthesis and secretion of syringomycin and syringopeptin belong to the SyrF regulon. Vector pMEKm12 was successfully used to express both SalA an...

The Arabidopsis mitogen-activated protein kinase (MAPK) kinase 2 (MKK2) was shown to mediate cold and salt stress responses through activation of the two MAP kinases MPK4 and MPK6. Transcriptome analysis of plants expressing constitutively active MKK2 (MKK2-EE plants) showed altered expression of genes induced by abiotic stresses but also a significant number of genes involved in defense respon...

We investigated indole-3-acetic acid (IAA) production by 57 pathovars of Pseudomonas syringae and related species. Most of those analyzed produced IAA, especially in the presence of tryptophan. Eight strains produced high IAA concentrations in the absence of Trp. The iaaM and iaaH genes of P. savastanoi pv. savastanoi were detected in a limited number of strains only, including the eight above-...