Control of Ascorbate Peroxidase 2 expression by hydrogen peroxide and leaf water status during excess light stress reveals a functional organisation of Arabidopsis leaves
Article first published online: 28 FEB 2003
The Plant Journal
Volume 33, Issue 4, pages 691–705, February 2003
How to Cite
Fryer, M. J., Ball, L., Oxborough, K., Karpinski, S., Mullineaux, P. M. and Baker, N. R. (2003), Control of Ascorbate Peroxidase 2 expression by hydrogen peroxide and leaf water status during excess light stress reveals a functional organisation of Arabidopsis leaves. The Plant Journal, 33: 691–705. doi: 10.1046/j.1365-313X.2003.01656.x
- Issue published online: 28 FEB 2003
- Article first published online: 28 FEB 2003
- Received 31 July 2002; revised 1 November 2002; accepted 19 November 2002.
- abscisic acid;
- bundle sheath;
- photosynthetic electron transport;
- reactive oxygen species
In Arabidopsis leaves, high light stress induces rapid expression of a gene encoding a cytosolic ascorbate peroxidase (APX2), whose expression is restricted to bundle sheath cells of the vascular tissue. Imaging of chlorophyll fluorescence and the production of reactive oxygen species (ROS) indicated that APX2 expression followed a localised increase in hydrogen peroxide (H2O2) resulting from photosynthetic electron transport in the bundle sheath cells. Furthermore, leaf transpiration rate also increased prior to APX2 expression, suggesting that water status may also be involved in the signalling pathway. Abscisic acid stimulated APX2 expression. Exposure of ABA-insensitive mutants (abi1-1, abi2-1) to excess light resulted in reduced levels of APX2 expression and confirmed a role for ABA in the signalling pathway. ABA appears to augment the role of H2O2 in initiating APX2 expression. This regulation of APX2 may reflect a functional organisation of the leaf to resolve two conflicting physiological requirements of protecting the sites of primary photosynthesis from ROS and, at the same time, stimulating ROS accumulation to signal responses to changes in the light environment.