Arabidopsis proteins important for modulating defense responses to Pseudomonas syringae that secrete HopW1-1
Article first published online: 7 FEB 2008
© 2008 The Authors. Journal compilation © 2008 Blackwell Publishing Ltd
The Plant Journal
Volume 54, Issue 3, pages 452–465, May 2008
How to Cite
Lee, M. W., Jelenska, J. and Greenberg, J. T. (2008), Arabidopsis proteins important for modulating defense responses to Pseudomonas syringae that secrete HopW1-1. The Plant Journal, 54: 452–465. doi: 10.1111/j.1365-313X.2008.03439.x
- Issue published online: 7 FEB 2008
- Article first published online: 7 FEB 2008
- Received 15 October 2007; revised 18 January 2008; accepted 22 January 2008.
- signal transduction;
- salicylic acid;
Plant infection responses result from the interaction of pathogen-derived molecules with host components. For the bacterial pathogen Pseudomonas syringae, these molecules are often effector proteins (Hops) that are injected into plant cells. P. syringae carrying hopW1-1 have restricted host range on some Arabidopsis thaliana accessions. At least two Arabidopsis genomic regions are important for the natural variation that conditions resistance to P. syringae/hopW1-1. HopW1-1 elicits a resistance response, and consequently the accumulation of the signal molecule salicylic acid (SA) and transcripts of HWI1 (HopW1-1-Induced Gene1). This work identified three HopW1-1-interacting (WIN) plant proteins: a putative acetylornithine transaminase (WIN1), a protein phosphatase (WIN2) and a firefly luciferase superfamily protein (WIN3). Importantly, WIN2 and WIN3 are partially required for HopW1-1-induced disease resistance, SA production and HWI1 expression. The requirement for WIN2 is specific for HopW1-1-induced resistance, whereas WIN3 is important for responses to several effectors. Overexpression of WIN2 or WIN3 confers resistance to virulent P. syringae, which is consistent with these proteins being defense components. Several known genes important for SA production or signaling are also partially (EDS1, NIM1/NPR1, ACD6 and ALD1) or strongly (PAD4) required for the robust resistance induced by HopW1-1, suggesting a key role for SA in the HopW1-1-induced resistance response. Finally, WIN1 is an essential protein, the overexpression of which over-rides the resistance response to HopW1-1 (and several other defense-inducing effectors), and delays SA and HWI1 induction. Thus, the WIN proteins have different roles in modulating plant defense.