Sources and Effects of Reactive Oxygen Species in Plants

Abstract

Although basic oxygen metabolism is similar in plants and animals, there are several aspects unique to plants. Plants have photosynthetic electron transport in the chloroplast that produces oxygen and is accompanied by the production of reactive oxygen species (ROS). Other processes unique to plants that involve ROS are lignification of plant cell walls, which is important in normal growth as well as pathogenesis, and senescence, which is essential to fruit ripening, seed production, and overwintering. We have used a broad definition of the term ROS to include reactive species in which the active moiety involves oxygen (i.e., phenoxy radicals involved in lignin synthesis and acyl peroxides involved in membrane peroxidation).In this review we will explore the many processes in plant physiology where ROS metabolism appears to be strongly associated. The study of ROS involvement in plant processes is being conducted in several laboratories and we are not able to address the findings of each group in the scope of this review. However, we will touch on a wide spectrum of topics currently of interest in plant systems. In addition, we have included a discussion of the use of transgenic plants and the unique insights they can provide in studies of oxidative stress.

Role of thylakoid Ndh complex and peroxidase in the protection against photo‐oxidative stress: fluorescence and enzyme activities in wild‐type and ndhF‐deficient tobacco

“…An appropriate H + gradient across the thylakoid membrane is required for the dissipation of excess radiation incident in PSII as heat (Burrows et al 1998) by the transfer of excitation to zeaxanthin formed by the xanthophyll cycle. Otherwise, the formation of singlet oxygen and over‐reduction of the electron transporters will enhance photo‐oxidative damage (Baker and Orlandi 1999). NPQ is a measure of heat dissipation, and it has been concluded that the Ndh complex is required to maintain an appropriate NPQ level (Burrows et al 1998).…”

Temporal evolution of the Arabidopsis oxidative stress response

“…This complex of biochemical, genetic and structural changes is termed the stress-or defense response, depending on whether the inciting agent is abiotic or biotic. The plant stress/defense response includes the production of reactive oxygen species (ROS), the biosynthesis of antimicrobial compounds, cell wall proteins, antioxidants, and signaling molecules, as well as elaboration of the apoptotic hypersensitive response (HR) and the development of systemic acquired resistance (SAR) (Lamb and Dixon, 1994;Baker and Orlandi, 1995;Baker et al, 1997;Lamb and Dixon, 1997;Baker and Orlandi, 1999). Ozone (O 3 ), a component of photochemical smog, represents an oxidative stress to living organisms and is a major atmospheric pollutant, damaging crops and forests (Runeckles and Chevonne, 1992).…”

Different Signaling and Cell Death Roles of Heterotrimeric G Protein α and β Subunits in the Arabidopsis Oxidative Stress Response to Ozone

“…The oxidative burst, a transient increase in reactive oxygen species (ROS), predominantly superoxide (_O 2 ÿ ) and hydrogen peroxide (H 2 O 2 ), is among the first biochemical responses of plants to pathogen attack and abiotic stress (Mehdy, 1994;Lamb and Dixon, 1997;Alvarez et al, 1998;Baker and Orlandi, 1999). Although the deleterious effects of ROS have long been known, recognition of their role in cell signaling and regulation of gene expression is relatively recent and still poorly understood (Sauer et al, 2001;Droge, 2002;Ermak and Davies, 2002).…”