Present address: Alayne Cuzick, Plant-Pathogen Interactions Division, Rothamsted Research, Harpenden, Herts. AL5 2JQ, UK.
EDM2 is required for RPP7-dependent disease resistance in Arabidopsis and affects RPP7 transcript levels
Article first published online: 24 JAN 2007
The Plant Journal
Volume 49, Issue 5, pages 829–839, March 2007
How to Cite
Eulgem, T., Tsuchiya, T., Wang, X.-J., Beasley, B., Cuzick, A., Tör, M., Zhu, T., McDowell, J. M., Holub, E. and Dangl, J. L. (2007), EDM2 is required for RPP7-dependent disease resistance in Arabidopsis and affects RPP7 transcript levels. The Plant Journal, 49: 829–839. doi: 10.1111/j.1365-313X.2006.02999.x
- Issue published online: 2 FEB 2007
- Article first published online: 24 JAN 2007
- Received 4 July 2006; revised 15 October 2006; accepted 18 October 2006.
- Arabidopsis thaliana;
- Hyaloperonospora parasitica;
- disease resistance gene;
- EDM2 (enhanced downy mildew 2)-like proteins (ELPs);
- plant homeodomain (PHD) finger
Specific disease resistance of Arabidopsis thaliana against the Hyaloperonospora parasitica isolate Hiks1 (HpHiks1) is mediated by RPP7. Although this disease resistance gene encodes a typical nucleotide binding site leucine-rich repeat (NB-LRR) disease resistance protein, its function is independent of the defense hormone salicylic acid and most known genes required for plant immune responses. We identified EDM2 (enhanced downy mildew 2) in a genetic screen for RPP7 suppressors. Mutations of EDM2 phenocopy RPP7 mutations, but do not affect other tested disease resistance genes. We isolated EDM2 by map-based cloning. The predicted EDM2 protein is structurally unrelated to previously identified components of the plant immune system, bears typical features of transcriptional regulators, including plant homeodomain (PHD)-finger-like domains, and defines a plant-specific protein family. In edm2 mutants both constitutive and HpHiks1-induced RPP7 transcript levels are reduced, suggesting that EDM2 is either a direct or an indirect regulator of RPP7 expression. Microarray analyses defined a set of defense-associated genes, the expression of which is suppressed during successful HpHiks1 colonization of either rpp7 or edm2 plants. This transcriptional phenotype is counteracted by an EDM2/RPP7-dependent mechanism.