These authors contributed equally to this work.
Layers of defense responses to Leptosphaeria maculans below the RLM1- and camalexin-dependent resistances
Article first published online: 11 FEB 2009
© The Authors (2009). Journal compilation © New Phytologist (2009)
Volume 182, Issue 2, pages 470–482, April 2009
How to Cite
Persson, M., Staal, J., Oide, S. and Dixelius, C. (2009), Layers of defense responses to Leptosphaeria maculans below the RLM1- and camalexin-dependent resistances. New Phytologist, 182: 470–482. doi: 10.1111/j.1469-8137.2009.02763.x
- Issue published online: 27 MAR 2009
- Article first published online: 11 FEB 2009
- Received: 21 October 2008Accepted: 14 December 2008
- Arabidopsis thaliana;
- defense responses;
- Leptosphaeria maculans;
- Phoma lingam;
- quantitative real-time PCR
- • Plants have evolved different defense components to counteract pathogen attacks. The resistance locus resistance to Leptosphaeria maculans 1 (RLM1) is a key factor for Arabidopsis thaliana resistance to L. maculans. The present work aimed to reveal downstream defense responses regulated by RLM1.
- • Quantitative assessment of fungal colonization in the host was carried out using quantitative polymerase chain reaction (qPCR) and GUS expression analyses, to further characterize RLM1 resistance and the role of salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) in disease development. Additional assessments of A. thaliana mutants were performed to expand our understanding of this pathosystem.
- • Resistance responses such as lignification and the formation of vascular plugs were found to occur in an RLM1-dependent manner, in contrast to the RLM1-independent increase in reactive oxygen species at the stomata and hydathodes. Analyses of mutants defective in hormone signaling in the camalexin-free rlm1Lerpad3 background revealed a significant influence of JA and ET on symptom development and pathogen colonization.
- • The overall results indicate that the defense responses of primary importance induced by RLM1 are all associated with physical barriers, and that responses of secondary importance involve complex cross-talk among SA, JA and ET. Our observations further suggest that ET positively affects fungal colonization.