Oxidative Stress in Plants

Reactive oxygen intermediates (ROI) are toxic byproducts of oxygen reduction, continuously produced in cells during normal metabolism or stress. They play an important role in many signaling events related to biotic or abiotic stresses, programmed cell death, and hormonal action. Although our understanding of ROI metabolism in plants has considerably advanced in recent years, very little is known about the signal transduction pathway(s) associated with ROI sensing in cells. In my laboratory we study different Arabidopsis mutants, and transgenic tobacco plants, deficient in ROI scavenging genes. We are using Affymetrix chips and other molecular techniques to study gene expression in these plants and to identify different signal transduction components involved in ROI sensing in plants. I also collaborate with different labs to perform a proteomic analysis of oxidized proteins (Dr. David Oliver, ISU) and metabolic profiling (Dr. Vladimir Shulaev, VT) of these plants. My goal is to elucidate the signal transduction pathway activated in plants in response to elevated levels of ROI. Through a comprehensive analysis of gene expression, coupled with genetic crosses, I am working toward identifying and characterizing key components of this signaling pathway.

Mittler, R., Hallak-Herr, E., Orvar, B.L., Van Camp, W., Willekens, H., Inze, D. and Ellis, B.E. (1999) Transgenic tobacco plants with reduced capability to detoxify reactive oxygen intermediates are hyper-responsive to pathogen infection. Proc. Natl. Acad. Sci. USA. 96, 14165-14170.

Rizhsky, L. Hallak-Herr, E., Van Breusegem, F., Rachmilevitch, S., Rodermel, S., Inzé, D. and Mittler, R. (2002) Double antisense plants with suppressed expression of ascorbate peroxidase and catalase are less sensitive to oxidative stress than single antisense plants with suppressed expression of ascorbate peroxidase or catalase. Plant J. 32, 329-342.

Mittler, R. (2002) Oxidative stress, antioxidants, and stress tolerance. Trends Plant Sci. 7, 405-410.

Pnueli, L., Liang, H., Rozenberg, M. and Mittler, R. (2003) Growth suppression, altered stomatal responses, and augmented induction of heat shock proteins in cytosolic ascorbate peroxidase (Apx1)-deficient Arabidopsis plants. Plant J. 34, 187-203.

Rizhsky, L., Liang, H. and Mittler, R. (2003) The water-water cycle is essential for chloroplast protection in the absence of stress. J. Biol. Chem. 278, 38921-38925.

Rizhsky L., Davletova S., Liang H. and Mittler R. (2003) The zinc-finger protein Zat12 is required for cytosolic ascorbate peroxidase 1 expression during oxidative stress in Arabidopsis. J. Biol. Chem. 279, 11736-11743

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

Davletova, S., Rizhsky, L.,  Liang, H., Shengqiang, D., Oliver, D., Coutu, J., Shulaev, V., Schlauch, K. and Mittler R. (2004) Cytosolic Ascorbate Peroxidase 1 is a Central Component of the Reactive Oxygen Gene Network of Arabidopsis. The Plant Cell, 17.268-281

Davletova S, Schlauch K, Coutu J, Mittler R (2005) The zinc-finger protein Zat12 plays a central role in reactive oxygen and abiotic stress signaling in Arabidopsis. Plant Physiology,139, 847–856.

Suzuki N, Mittler R (2006) Reactive oxygen species and temperature stresses: A delicate balance between signaling and destruction. Physiol. Plant. 126, 45-51.