Levansucrases are bacterial extracellular enzymes that act on sucrose producing b-2,6-linked fructans of varied chain length. We summarize here our up-to-date results on (i) novel methods for the production of heterologous levansucrase proteins in Escherichia coli, (ii) biochemical characterization of the levansucrases encoded in the genome of a tomato and Arabidopsis pathogen Pseudomonas syrin...

BACKGROUND Under the threat of global climatic change and food shortages, it is essential to take the initiative to obtain a comprehensive understanding of common and specific defence mechanisms existing in plant systems for protection against different types of biotic invaders. We have implemented an integrated approach to analyse the overall transcriptomic reprogramming and systems-level defe...

Heterotrimeric G-proteins have been proposed to be involved in many aspects of plant disease resistance but their precise role in mediating nonhost disease resistance is not well understood. We evaluated the roles of specific subunits of heterotrimeric G-proteins using knock-out mutants of Arabidopsis Gα, Gβ and Gγ subunits in response to host and nonhost Pseudomonas pathogens. Plants lacking f...

citrus blast is one of the important diseases of citrus in north of iran. the disease causes considerable damage during and immediately after the cold seasons. the causal agents have epiphytic survival on diverse weeds during spring and summer. during 2009-2010, samples were collected from several candidate weed plants including: poa annua, phalaris canariensis, sorghum halepense, cynodon dacty...

Although chemically defined media have been developed and widely used to study the expression of virulence factors in the model plant pathogen Pseudomonas syringae, it has been difficult to link specific medium components to the induction response. Using a chemostat system, we found that iron is the limiting nutrient for growth in the standard hrp-inducing minimal medium and plays an important ...

Mutations in the global regulatory genes gacS and gacA render Pseudomonas syringae pv. syringae strain B728a completely nonpathogenic in foliar infiltration assays on bean plants. It had been previously demonstrated that gac genes regulate alginate production in Pseudomonas species, while other published work indicated that alginate is involved in the pathogenic interaction of P. syringae on be...

Bacteriophages isolated from culture supernatants of Pseudomonas syringae pv. syringae and from sewage were identified. The DNA from each phage was isolated and digested with the restriction endonuclease EcoRI. Eight isolates were determined to be different, with two phage isolates from sewage having restriction patterns identical to two phages from culture supernatants. The sizes of the phage ...

Copper-resistant strains of Pseudomonas syringae carrying the cop operon produce periplasmic copper-binding proteins, and this sequestration outside the cytoplasm has been proposed as a resistance mechanism. In this study, strain PS61 of P. syringae carrying the cloned cop operon accumulated more total cellular copper than without the operon. Several other copper-resistant pseudomonads with hom...