Reactive oxygen species (ROS) are key players in the regulation of plant development, stress responses and programmed cell death. A fine-tuned balance between ROS production and scavenging is hence crucial for plant survival. In Arabidopsis this delicate ROS management is steered by a gene network that comprises at least 152 genes (Mittler et al., 2004). While the importance of ROS for cellular signaling has been established, relatively little is known about how ROS stimuli are perceived, transduced.

Using tobacco and Arabidopsis model systems we have demonstrated a signaling role for H₂O₂ in launching both a defense response and cell death events. More recently, we started to dissect the transcriptional gene networks during H₂O₂ stress and pinpoint genes that are potential candidates for innovative molecular breeding strategies to develop stress-tolerant crops. Using both microarrays and cDNA-AFLP technology, expression profiles were compared between wild-type and catalase-deficient plants. These genome-wide analyses allowed us to reveal the expression characteristics of complete pathways and functional categories during H₂O₂ stress and several transcription factors and candidate regulatory genes involved in H₂O₂ transcriptional gene networks were identified. This analysis allowed us to identify a high-light induced transcriptional cluster involved in flavonoid biosynthesis (Vandenabeele et al., 2004, Vanderauwera et al., 2005). A recent meta-analysis of transcriptome data revealed a significant intersection between H₂O₂-deregulated genes and abiotic stress induced gene expression, hereby molecularly consolidating the signaling role of ROS within the abiotic stress response. Within this study we identified transcriptomic footprints that disclose the specificity of ROS signaling in

The best studied examples of ROS-driven cell death events in plants are those following the typical biphasic oxidative burst during the hypersensitive response and ozone stress. Although it is becoming more and more evident that programmed cell death is also induced during abiotic stresses (Van Breusegem and Dat, 2006; Gechev et al., 2006). During plant cell death a strong interplay exists between ROS and other phytohormones. Recently we have consolidated the cross-talk between nitric oxide (NO) and H₂O₂ during plant cell death and obtained new insights in the early transcriptional response of plants to increased NO and H₂O₂ levels by identifying target genes of the combined action of NO and H₂O₂ during the induction of plant cell death (Zago et al., 2006).

Further reading

Gadjev, I., Vanderauwera, S., Gechev, T.S., Laloi, C., Minkov, I.N., Shulaev, V., Apel, K., Inze, D., Mittler, R., and Van Breusegem, F. (2006). Transcriptomic footprints disclose specificity of reactive oxygen species signaling in Arabidopsis. Plant Physiol. 141, 436-445.

Schuhegger, R., Ihring, A., Gantner, S., Bahnweg, G., Knappe, C., Vogg, G., Hutzler, P., Schmid, M., Van Breusegem, F., Eberl, L., Hartmann, A., and Langebartels, C. (2006). Induction of systemic resistance in tomato by N-acyl-L-homoserine lactone-producing rhizosphere bacteria. Plant Cell Environ. 29, 909-918

Gechev, T.S., Van Breusegem, F., Stone, J.M., Denev, I., and Laloi, C. (2006). Reactive oxygen species as signals that modulate plant stress responses and programmed cell death. Bioessays 28, 1091-1101.

Zago, E., Morsa, S., Dat, J.F., Alard, P., Ferrarini, A., Inze, D., Delledonne, M., and Van Breusegem, F. (2006). Nitric oxide- and hydrogen peroxide-responsive gene regulation during cell death induction in tobacco. Plant Physiol. 141, 404-411.

Van Breusegem, F., and Dat, J.F. (2006). Reactive oxygen species in plant cell death. Plant Physiol 141, 384-390.

Vanderauwera, S., Zimmermann, P., Rombauts, S., Vandenabeele, S., Langebartels, C., Gruissem, W., Inze, D., and Van Breusegem, F. (2005). Genome-wide analysis of hydrogen peroxide-regulated gene expression in Arabidopsis reveals a high light-induced transcriptional cluster involved in anthocyanin biosynthesis. Plant Physiol. 139, 806-821.

Montillet, J.L., Chamnongpol, S., Rusterucci, C., Dat, J., van de Cotte, B., Agnel, J.P., Battesti, C., Inze, D., Van Breusegem, F., and Triantaphylides, C. (2005). Fatty acid hydroperoxides and H2O2 in the execution of hypersensitive cell death in tobacco leaves. Plant Physiol. 138, 1516-1526.

Vandenabeele, S., Vanderauwera, S., Vuylsteke, M., Rombauts, S., Langebartels, C., Seidlitz, H.K., Zabeau, M., Van Montagu, M., Inze, D., and Van Breusegem, F. (2004). Catalase deficiency drastically affects gene expression induced by high light in Arabidopsis thaliana. Plant J. 39, 45-58.

Mittler, R., Vanderauwera, S., Gollery, M., and Van Breusegem, F. (2004). Reactive oxygen gene network of plants. Trends Plant Sci. 9, 490-498.

Vandenabeele, S., Van Der Kelen, K., Dat, J., Gadjev, I., Boonefaes, T., Morsa, S., Rottiers, P., Slooten, L., Van Montagu, M., Zabeau, M., Inze, D., and Van Breusegem, F. (2003). A comprehensive analysis of hydrogen peroxide-induced gene expression in tobacco. Proc Natl Acad Sci USA 100, 16113-16118.

Dat, J.F., Pellinen, R., Beeckman, T., Van De Cotte, B., Langebartels, C., Kangasjarvi, J., Inze, D., and Van Breusegem, F. (2003). Changes in hydrogen peroxide homeostasis trigger an active cell death process in tobacco. Plant J. 33, 621-632.