IBIS-Flora

Angiosperm Flora of India

PopW of Ralstonia solanacearum, a new two-domain harpin targeting the plant cell wall

Publication Type:Journal Article
Year of Publication:2010
Authors:LI, JIAN-GANG, LIU, HONG-XIA, Cao, J, CHEN, LI-FENG, GU, CHUN, ALLEN, CAITILYN, GUO, JIAN-HUA
Journal:Molecular Plant Pathology
Volume:11
Issue:3
Date Published:2010
ISBN Number:1364-3703
Keywords:glycine
Abstract:

Harpins are extracellular glycine-rich proteins eliciting a hypersensitive response (HR). In this study, we identified a new harpin, PopW, from Ralstonia solanacearum strain ZJ3721. This 380-amino-acid protein is acidic, rich in glycine and serine, and lacks cysteine. When infiltrated into the leaves of tobacco (non-host), PopW induced a rapid tissue collapse via a heat-stable but protease-sensitive HR-eliciting activity. PopW has an N-terminal harpin domain (residues 1–159) and a C-terminal pectate lyase (PL) domain (residues 160–366); its HR-eliciting activity depends on its N-terminal domain. Analyses of subcellular localization and plasmolysis demonstrated that PopW targeted the onion cell wall. This was further confirmed by its ability to specifically bind to calcium pectate, a major component of the plant cell wall. However, PopW had no detectable PL activity. Western blotting revealed that PopW was secreted by the type III secretion system in an hrpB-dependent manner. Gene sequencing indicated that popW is conserved among 20 diverse strains of R. solanacearum. A popW-deficient mutant retained the ability of wild-type strain ZJ3721 to elicit HR in tobacco and to cause wilt disease in tomato (a host). We conclude that PopW is a new cell wall-associated, hrpB-dependent, two-domain harpin that is conserved across the R. solanacearum species complex.

URL:http://dx.doi.org/10.1111/j.1364-3703.2010.00610.x
Short Title:Molecular Plant Pathology
Taxonomic name: 
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Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith