Journal
PLANT JOURNAL
Volume 57, Issue 4, Pages 706-717Publisher
WILEY
DOI: 10.1111/j.1365-313X.2008.03723.x
Keywords
plant immunity; effector; Pseudomonas syringae; virulence; pore formation; receptor
Categories
Funding
- Deutsche Forschungsgemeinschaft (GKI 685)
- European Community Biotechnology [BIO-CT97-2244]
- The Academy of Finland
Ask authors/readers for more resources
The HrpZ1 gene product from phytopathogenic Pseudomonas syringae is secreted in a type-III secretion system-dependent manner during plant infection. The ability of HrpZ1 to form ion-conducting pores is proposed to contribute to bacterial effector delivery into host cells, or may facilitate the nutrition of bacteria in the apoplast. Furthermore, HrpZ1 is reminiscent of a pathogen-associated molecular pattern (PAMP) that triggers immunity-associated responses in a variety of plants. Here, we provide evidence that the ion pore formation and immune activation activities of HrpZ1 have different structure requirements. All HrpZ1 orthologous proteins tested possess pore formation activities, but some of these proteins fail to trigger plant defense-associated responses. In addition, a C-terminal fragment of HrpZ1 retains the ability to activate plant immunity, whereas ion pore formation requires intact HrpZ1. Random insertion mutagenesis of HrpZ1 further revealed the C terminus to be important for the PAMP activity of the protein. HrpZ1 binds to plant membranes with high affinity and specificity, suggesting that the activation of plant immunity-associated responses by HrpZ1 is receptor-mediated. Our data are consistent with dual roles of HrpZ1 as a virulence factor affecting host membrane integrity, and as a microbial pattern governing the activation of plant immunity during infection.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available