Tiina A Palomäki

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We have used an hrp-positive strain of the soft rot pathogen Erwinia carotovora subsp. carotovora to elucidate plant responses to this bacterial necrotroph. Purified virulence determinants, harpin (HrpN) and polygalacturonase (PehA), were used as tools to facilitate this analysis. We show that HrpN elicits lesion formation in Arabidopsis and tobacco and(More)
A set of gene fusions was constructed between the pehA gene encoding the secreted endopolygalacturonase (PehA) and the bla gene coding for a normally periplasmic beta-lactamase (Bla). The resulting hybrid proteins were specifically and actively routed out of the cells via the Out-terminal branch of the general secretory pathway (GSP) in Erwinia carotovora(More)
Efficient response to environmental cues is crucial to successful infection by plant-pathogenic bacteria such as Erwinia carotovora ssp. carotovora. The expression of the main virulence genes of this pathogen, encoding extracellular enzymes that degrade the plant-cell wall, is subject to complex regulatory machinery where two-component systems play an(More)
Intramolecular information specifying protein secretion through the type II (GSP) pathway of Gram-negative bacteria was investigated. Two regions of the polygalacturonase (PehA) of Erwinia carotovora containing residues proposed to be included in a targeting motif were located, one close to the C-terminus between residues 342 and 369 and another between(More)
An intact C-terminus was previously shown to be required for stability and secretion of the polygalacturonase (PehA) in Erwinia carotovora ssp. carotovora. Here we have analyzed the effects of amino acid (aa) substitutions generated to five C-terminal positions of PehA. Conservation of two hydrophobic and one non-hydrophobic residue (V372, V374 and N371,(More)
A cellulase-producing clone was isolated from a genomic library of the Erwinia rhapontici (Millard) Burkholder strain NCPPB2989. The corresponding gene, named celA, encodes an endoglucanase (EC 3.2.1.4) with the extremely low pH optimum of 3.4 and a temperature optimum between 40 and 50 degrees C. A single ORF of 999 nt was found to be responsible for the(More)
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