Present address: Botanical Institute, University of Basel, CH-4056 Basel, Switzerland.
Arabidopsis MAP kinase phosphatase 1 and its target MAP kinases 3 and 6 antagonistically determine UV-B stress tolerance, independent of the UVR8 photoreceptor pathway
Article first published online: 13 SEP 2011
© 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd
The Plant Journal
Volume 68, Issue 4, pages 727–737, November 2011
How to Cite
González Besteiro, M. A., Bartels, S., Albert, A. and Ulm, R. (2011), Arabidopsis MAP kinase phosphatase 1 and its target MAP kinases 3 and 6 antagonistically determine UV-B stress tolerance, independent of the UVR8 photoreceptor pathway. The Plant Journal, 68: 727–737. doi: 10.1111/j.1365-313X.2011.04725.x
- Issue published online: 9 NOV 2011
- Article first published online: 13 SEP 2011
- Accepted manuscript online: 25 JUL 2011 01:29PM EST
- Received 28 June 2011; accepted 22 July 2011; published online 13 September 2011.
- MAP kinase phosphatase;
- UV-B signalling;
- UV RESISTANCE LOCUS 8;
- abiotic stress;
Plants perceive UV-B radiation as an informational signal by a pathway involving UVR8 as UV-B photoreceptor, activating photomorphogenic and acclimation responses. In contrast, the response to UV-B as an environmental stress involves mitogen-activated protein kinase (MAPK) signalling cascades. Whereas the perception pathway is plant specific, the UV-B stress pathway is more broadly conserved. Knowledge of the UV-B stress-activated MAPK signalling pathway in plants is limited, and its potential interplay with the UVR8-mediated pathway has not been defined. Here, we show that loss of MAP kinase phosphatase 1 in the mutant mkp1 results in hypersensitivity to acute UV-B stress, but without impairing UV-B acclimation. The MKP1-interacting proteins MPK3 and MPK6 are activated by UV-B stress and are hyperactivated in mkp1. Moreover, mutants mpk3 and mpk6 exhibit elevated UV-B tolerance and partially suppress the UV-B hypersensitivity of mkp1. We show further that the MKP1-regulated stress-response MAPK pathway is independent of the UVR8 photoreceptor, but that MKP1 also contributes to survival under simulated sunlight. We conclude that, whereas UVR8-mediated acclimation in plants promotes UV-B-induced defence measures, MKP1-regulated stress signalling results when UV-B protection and repair are insufficient and damage occurs. The combined activity of these two mechanisms is crucial to UV-B tolerance in plants.