Present address: Department of Biology, Massachusetts Institute of Technology, Cambridge, 02139 MA, USA.
Transcriptional reprogramming regulated by WRKY18 and WRKY40 facilitates powdery mildew infection of Arabidopsis
Article first published online: 4 NOV 2010
© 2010 The Authors. The Plant Journal © 2010 Blackwell Publishing Ltd
The Plant Journal
Volume 64, Issue 6, pages 912–923, December 2010
How to Cite
Pandey, S. P., Roccaro, M., Schön, M., Logemann, E. and Somssich, I. E. (2010), Transcriptional reprogramming regulated by WRKY18 and WRKY40 facilitates powdery mildew infection of Arabidopsis. The Plant Journal, 64: 912–923. doi: 10.1111/j.1365-313X.2010.04387.x
- Issue published online: 10 DEC 2010
- Article first published online: 4 NOV 2010
- Accepted manuscript online: 5 OCT 2010 02:58PM EST
- Received 21 July 2010; revised 3 September 2010; accepted 7 September 2010; published online 4 November 2010.
- chromatin immunoprecipitation;
- enhanced disease susceptibility 1;
- G. orontii;
- JAZ repressors;
- wrky18 wrky40 double mutant
The two closely related Arabidopsis transcription factors, WRKY18 and WRKY40, play a major and partly redundant role in PAMP-triggered basal defense. We monitored the transcriptional reprogramming induced by the powdery mildew fungus, Golovinomyces orontii, during early stages of infection with respect to the role of WRKY18/40. Expression of >1300 Arabidopsis genes was differentially altered already 8 hours post infection (hpi), indicating rapid pre-penetration signaling between the pathogen and the host. We found that WRKY18/40 negatively affects pre-invasion host defenses and deduced a subset of genes that appear to be under WRKY18/40 control. A mutant lacking the WRKY18/40 repressors executes pathogen-dependent but exaggerated expression of some defense genes leading, for example, to strongly elevated levels of camalexin. This implies that WRKY18/40 act in a feedback repression system controlling basal defense. Moreover, using chromatin immunoprecipitation (ChIP), direct in vivo interactions of WRKY40 to promoter regions containing W box elements of the regulatory gene EDS1, the AP2-type transcription factor gene RRTF1 and to JAZ8, a member of the JA-signaling repressor gene family were demonstrated. Our data support a model in which WRKY18/40 negatively modulate the expression of positive regulators of defense such as CYP71A13, EDS1 and PAD4, but positively modulate the expression of some key JA-signaling genes by partly suppressing the expression of JAZ repressors.