The hrp cluster in Pseudomonas savastanoi pathovars and construction of knocking out mutants in hrp genes

The Type Three Secretion System (TTSS), highly conserved among a wide range of pathogenic animal and plant Gram-negative bacteria, is devoted to export effector proteins directly from the bacterial cell into the cytoplasm of the potential host. TTSS are clustered in "pathogenicity islands"...

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Bibliographic Details
Published in:Journal of plant pathology 2004-12, Vol.86 (4), p.340-340
Main Authors: Santilli, E, Lambertsen, L, Perez-Martinez, I, Michelotti, V, Beuzon, C, Murillo, J, Ramos, C, Tegli, S
Format: Article
Language:English
Subjects:
Pseudomonas savastanoi
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Summary:The Type Three Secretion System (TTSS), highly conserved among a wide range of pathogenic animal and plant Gram-negative bacteria, is devoted to export effector proteins directly from the bacterial cell into the cytoplasm of the potential host. TTSS are clustered in "pathogenicity islands" (PAI), whose core is composed of the so-called hrp (hypersensitive response and pathogenicity) genes. The genes encoding the TTSS of P. syringae were originally identified in P. savastanoi pv. phaseolicola, whose entire hrp cluster has been recently sequenced and characterised. The entire hrpC operon of P. savastanoi pv. savastanoi (Pss) has been also sequenced, and the involvement demonstrated of the hrpC gene in the development of the symptoms and in the elicitation of the HR on host and non-host plants, respectively. In the present work the entire hrp clusters of Pss and of the other two pathovars, P. savastanoi pv. nerii and pv. fraxini, have been sequenced, revealing a very high degree of homology and conservation. According to these sequences, specific primers were designed to amplify the entire sequence of the genes hrpRS (operon RS), and hrpA, hrpB and hrpZ (operon Z), hrcV (operon J), hrpL and hrpK, using Pss DNA as template. These genes were cloned in the vector pUC18Not-Km, following a strategy to construct a deletion cassette able to give in Pss the exact deletion of the coding sequence of the gene of interest after homologous recombination, mediated by the suicide vector pKAS32.
ISSN:1125-4653