Hydrogen peroxide- and glutathione-associated mechanisms of acclimatory stress tolerance and signalling

Abstract

I. M. 1997. Hydrogen peroxideand glutathione-associated mechanisms of acclimatory stress tolerance and signalling. -Physiol. Plant. 100: 241-254.Plants adapt to environmental stresses through specific genetic responses. The molecular mechanisms associated with signal transduction, leading to changes in gene expression early in the stress response, are largely unknown. It is clear, however, that gene expression associated with acclimatory responses is sensitive to the redox state of the cell. Of the many components which contribute to the redox balance of the cell, two factors have been shown to be crucial in mediating stress responses. Thiol/disulphide exchange reactions, particularly involving the glutathione pool and the generation of the oxidant H2O2, are central components of signal transduction in both environmental and biotic stresses. These molecules are multifunctional triggers, modulating metabolism and gene expression. Both are able to cross biological membranes and diffuse or be transported long distances from their sites of origin. Glutathione and H2O2 may act alone or in unison, in intracellular and systemic signalling systems, to achieve acclimation and tolerance to biotic and abiotic stresses.

Ammonium enhances resistance to salinity stress in citrus plants

“…The role of some ROS, such as signal molecules in biotic or abiotic stress, is of biological significance because the production of these molecules could benefit the plants brought into a state of acclimation (Foyer et al, 1997, Jubany-Marí et al, 2009. Similarly, plant hormones play an important role in response to unfavorable environmental conditions.…”

Oxidative Stress Induction by Lead in Leaves of Radish (Raphanus sativus) Seedlings

“…All these eventually lead to cell death. To combat oxidative damage, plants have antioxidant defense system comprising of enzymes of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), glutathione reductase (GR), and the non-enzymic constituents such as reduced glutathione (GSH) and ascorbate (As) that remove, neutralize, and scavenge ROS (Foyer et al, 1997;Lee et al, 1976;Navari-Lazzo and Quartacci, 2001). SOD dismutates O 2 -to H 2 O 2 , and this is decomposed to H 2 O by POD and CAT, so that the accumulation of O 2 -and H 2 O 2 is effectively prevented (Liu et al, 2002).…”

Mineral nutrient imbalance, total antioxidants level and DNA damage in common bean (Phaseolus vulgaris L.) exposed to heavy metals

“…A lot of information is available on the effect of metals on various antioxidant processes in plants (Van Assche and Clijsters 1990;Verma and Dubey 2003;Hou et al 2007;Radić et al 2009;Israr et al 2006). One possible mechanism, in which elevated concentrations of heavy metals may damage plant tissues, is the stimulation of free radical production by imposing oxidative stress (Foyer et al 1997). Heavy metals like copper and iron can be toxic because of their participation in redox cycles producing hydroxyl radicals ( .…”