HrpZPsph from the plant pathogen Pseudomonas syringae pv. phaseolicola binds to lipid bilayers and forms an ion-conducting pore invitro

Abstract

The hrp gene clusters of plant pathogenic bacteria control pathogenicity on their host plants and ability to elicit the hypersensitive reaction in resistant plants. Some hrp gene products constitute elements of the type III secretion system, by which effector proteins are exported and delivered into plant cells. Here, we show that the hrpZ gene product from the bean halo-blight pathogen, Pseudomonas syringae pv. phaseolicola (HrpZPsph), is secreted in an hrp-dependent manner in P. syringae pv. phaseolicola and exported by the type III secretion system in the mammalian pathogen Yersinia enterocolitica. HrpZPsph was found to associate stably with liposomes and synthetic bilayer membranes. Under symmetric ionic conditions, addition of 2 nM of purified recombinant HrpZ Psph to the cis compartment of planar lipid bilayers provoked an ion current with a large unitary conductivity of 207 pS. HrpZPsphrelated proteins from P. syringae pv. tomato or syringae triggered ion currents similar to those stimulated by HrpZPsph. The HrpZPsphmediated ion-conducting pore was permeable for cations but did not mediate fluxes of Cl ؊ . Such pore-forming activity may allow nutrient release and͞or delivery of virulence factors during bacterial colonization of host plants.

The Arabidopsis Wall Associated Kinase-Like 10 Gene Encodes a Functional Guanylyl Cyclase and Is Co-Expressed with Pathogen Defense Related Genes

“…The expression of the gene set was also induced by other pathogen derived elicitors including, bacterial secreted harpin, hypersensitive reaction and pathogenicity (Hrp)-Z (+2.37) [67] and syringolin A (+3.18) [68] and the oomycete-derived necrosis-inducing Phytophthora protein 1 (NPP1) (+2.23) [69].…”

Microbial manipulation of the amyloid fold

“…Harpins are heat-stable, type III-secreted proteins that plant pathogens inject into host cells and that induce a hypersensitive response (Kim et al, 2003, Wei et al, 1992). Although the mode of harpin toxicity is not completely understood, various harpins have been shown to interact with synthetic lipid membranes (Lee et al, 2001) and to depolarize plant cell membranes (Ahmad et al, 2001, Pike et al, 1998). Oh et al .…”

Pseudomonas aeruginosa Cytotoxicity Is Attenuated at High Cell Density and Associated with the Accumulation of Phenylacetic Acid

“…6). T3SS is the major virulence determinant of bacterial early infection and acute cytotoxicity [3]–[8]. Identification of PAA as a T3SS inhibitor provides a molecular basis to the early observation that the expression level of P. aerugionsa T3SS genes drops drastically at the stationary growth phase [18].…”

“…This protein secretion and delivery system acts by injecting effector proteins into host cells, and with which to modulate the host cellular activities in favor of infection [3], [4], [5]. T3SS is known to play various roles in host-pathogen interaction, including generation of pores in host cells and promoting bacterial internalization [6], [7], [8], induction of macrophage apoptosis [9], and inhibition of phagocytosis by changing the structure of macrophage actin skeleton [10].…”