Cross-talk between singlet oxygen-and hydrogen peroxide-dependent signaling of stress responses in Arabidopsis thaliana (original) (raw)
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Signaling role of reactive oxygen species in plants under stress
Russian Journal of Plant Physiology, 2012
The review considers the role of H 2 O 2 , 1 O 2 , , and the products of lipid peroxidation as sig naling molecules in the processes of stress signal transduction in plants. The data concerning possible ROS participation in transduction of stress signals from chloroplasts to the nuclear genome, H 2 O 2 involvement in transduction stress signals in cyanobacteria, and also the interactions between ROS and other signaling sys tems within the cell are presented. It is suggested that redox regulators, protein kinases/protein phosphatases, and transcription factors play a crucial role in the functioning of ROS dependent signaling systems in the plant cell.
Plant Cell, 2005
Reactive oxygen species (ROS), such as O 2 ÿ and H 2 O 2 , play a key role in plant metabolism, cellular signaling, and defense. In leaf cells, the chloroplast is considered to be a focal point of ROS metabolism. It is a major producer of O 2 ÿ and H 2 O 2 during photosynthesis, and it contains a large array of ROS-scavenging mechanisms that have been extensively studied. By contrast, the function of the cytosolic ROS-scavenging mechanisms of leaf cells is largely unknown. In this study, we demonstrate that in the absence of the cytosolic H 2 O 2-scavenging enzyme ascorbate peroxidase 1 (APX1), the entire chloroplastic H 2 O 2-scavenging system of Arabidopsis thaliana collapses, H 2 O 2 levels increase, and protein oxidation occurs. We further identify specific proteins oxidized in APX1-deficient plants and characterize the signaling events that ensue in knockout-Apx1 plants in response to a moderate level of light stress. Using a dominant-negative approach, we demonstrate that heat shock transcription factors play a central role in the early sensing of H 2 O 2 stress in plants. Using knockout plants for the NADPH oxidase D protein (knockout-RbohD), we demonstrate that RbohD might be required for ROS signal amplification during light stress. Our study points to a key role for the cytosol in protecting the chloroplast during light stress and provides evidence for cross-compartment protection of thylakoid and stromal/mitochondrial APXs by cytosolic APX1.
Plant Cell, 2005
Reactive oxygen species (ROS), such as O 2 ÿ and H 2 O 2 , play a key role in plant metabolism, cellular signaling, and defense. In leaf cells, the chloroplast is considered to be a focal point of ROS metabolism. It is a major producer of O 2 ÿ and H 2 O 2 during photosynthesis, and it contains a large array of ROS-scavenging mechanisms that have been extensively studied. By contrast, the function of the cytosolic ROS-scavenging mechanisms of leaf cells is largely unknown. In this study, we demonstrate that in the absence of the cytosolic H 2 O 2 -scavenging enzyme ascorbate peroxidase 1 (APX1), the entire chloroplastic H 2 O 2 -scavenging system of Arabidopsis thaliana collapses, H 2 O 2 levels increase, and protein oxidation occurs. We further identify specific proteins oxidized in APX1-deficient plants and characterize the signaling events that ensue in knockout-Apx1 plants in response to a moderate level of light stress. Using a dominant-negative approach, we demonstrate that heat shock transcription factors play a central role in the early sensing of H 2 O 2 stress in plants. Using knockout plants for the NADPH oxidase D protein (knockout-RbohD), we demonstrate that RbohD might be required for ROS signal amplification during light stress. Our study points to a key role for the cytosol in protecting the chloroplast during light stress and provides evidence for cross-compartment protection of thylakoid and stromal/mitochondrial APXs by cytosolic APX1.
The oxidative burst, during which large quantities of reactive oxygen species (ROS) like superoxide, hydrogen peroxide, hydroxyl radicals, peroxy radicals, alkoxy radicals, singlet oxygen, etc. are generated, is one of the earliest responses of plant cells under various abiotic and biotic stresses and natural course of senescence. In fact, reactions involving ROS are an inherent feature of plant cells and contribute to a process of oxidative deterioration that may lead ultimately to cell death. Sources of ROS include leakage of electrons from electron transport systems, decompartmentalization of iron which facilitates generation of highly reactive hydroxyl radicals, and also various biological reactions. The imposition of both abiotic and biotic stresses causes overproduction of ROS, which ultimately imposes a secondary oxidative stress in plant cells. Degradation of membrane lipids, resulting in free fatty acids, initiates oxidative deterioration by providing a substrate for enzyme lipoxygenase, causing membrane lipid peroxidation. Since lipid peroxidation is known to produce alkoxy, peroxy radicals as well as singlet oxygen, these reactions in the membrane are a major source of ROS in plant cells. Regulatory mechanisms function both at gene and protein level to coordinate antioxidant responses. Superimposed upon our understanding of ROS-induced oxidative damages and their protection by antioxidative system, is the newly discovered role of ROS in signalling processes. ROS like H 2 O 2 act as a signalling molecule, second messenger, mediating the acquisition of tolerance to both biotic and abiotic stresses. ROS as ubiquitous messengers of stress responses likely play a signalling role in various adaptive processes. Plants can sense, transduce and translate ROS signal into appropriate cellular responses with the help of some redox-sensitive proteins. Hydrogen peroxide has been implicated as a key factor mediating programmed cell death. Plants exposed to abiotic stresses can produce a systemic signal, a component of which may be H 2 O 2 which sets up an acclimatary response in unstressed regions of plants. ROS is also found to communicate with other signal molecules and the pathways forming part of signalling network that controls responses downstream of ROS.
Rapid Induction of Distinct Stress Responses after the Release of Singlet Oxygen in Arabidopsis
THE PLANT CELL ONLINE, 2003
The conditional fluorescent ( flu ) mutant of Arabidopsis accumulates the photosensitizer protochlorophyllide in the dark. After a dark-to-light shift, the generation of singlet oxygen, a nonradical reactive oxygen species, starts within the first minute of illumination and was shown to be confined to plastids. Immediately after the shift, plants stopped growing and developed necrotic lesions. These early stress responses of the flu mutant do not seem to result merely from physicochemical damage. Peroxidation of chloroplast membrane lipids in these plants started rapidly and led to the transient and selective accumulation of a stereospecific and regiospecific isomer of hydroxyoctadecatrieonic acid, free (13 S )-HOTE, that could be attributed almost exclusively to the enzymatic oxidation of linolenic acid. Within the first 15 min of reillumination, distinct sets of genes were activated that were different from those induced by superoxide/hydrogen peroxide. Collectively, these results demonstrate that singlet oxygen does not act primarily as a toxin but rather as a signal that activates several stress-response pathways. Its biological activity in Arabidopsis exhibits a high degree of specificity that seems to be derived from the chemical identity of this reactive oxygen species and/or the intracellular location at which it is generated.
Rapid Induction of Distinct Stress Responses after the Release of Singlet Oxygen in Arabidopsis[W]
The Plant Cell, 2003
The conditional fluorescent (flu) mutant of Arabidopsis accumulates the photosensitizer protochlorophyllide in the dark. After a dark-to-light shift, the generation of singlet oxygen, a nonradical reactive oxygen species, starts within the first minute of illumination and was shown to be confined to plastids. Immediately after the shift, plants stopped growing and developed necrotic lesions. These early stress responses of the flu mutant do not seem to result merely from physicochemical damage. Peroxidation of chloroplast membrane lipids in these plants started rapidly and led to the transient and selective accumulation of a stereospecific and regiospecific isomer of hydroxyoctadecatrieonic acid, free (13S)-HOTE, that could be attributed almost exclusively to the enzymatic oxidation of linolenic acid. Within the first 15 min of reillumination, distinct sets of genes were activated that were different from those induced by superoxide/hydrogen peroxide. Collectively, these results dem...
Current Science, 2005
The oxidative burst, during which large quantities of reactive oxygen species (ROS) like superoxide, hydrogen peroxide, hydroxyl radicals, peroxy radicals, alkoxy radicals, singlet oxygen, etc. are generated, is one of the earliest responses of plant cells under various abiotic and biotic stresses and natural course of senescence. In fact, reactions involving ROS are an inherent feature of plant cells and contribute to a process of oxidative deterioration that may lead ultimately to cell death. Sources of ROS include leakage of electrons from electron transport systems, decompartmentalization of iron which facilitates generation of highly reactive hydroxyl radicals, and also various biological reactions. The imposition of both abiotic and biotic stresses causes overproduction of ROS, which ultimately imposes a secondary oxidative stress in plant cells. Degradation of membrane lipids, resulting in free fatty acids, initiates oxidative deterioration by providing a substrate for enzyme lipoxygenase, causing membrane lipid peroxidation. Since lipid peroxidation is known to produce alkoxy, peroxy radicals as well as singlet oxygen, these reactions in the membrane are a major source of ROS in plant cells. Regulatory mechanisms function both at gene and protein level to coordinate antioxidant responses. Superimposed upon our understanding of ROS-induced oxidative damages and their protection by antioxidative system, is the newly discovered role of ROS in signalling processes. ROS like H 2 O 2 act as a signalling molecule, second messenger, mediating the acquisition of tolerance to both biotic and abiotic stresses. ROS as ubiquitous messengers of stress responses likely play a signalling role in various adaptive processes. Plants can sense, transduce and translate ROS signal into appropriate cellular responses with the help of some redox-sensitive proteins. Hydrogen peroxide has been implicated as a key factor mediating programmed cell death. Plants exposed to abiotic stresses can produce a systemic signal, a component of which may be H 2 O 2 which sets up an acclimatary response in unstressed regions of plants. ROS is also found to communicate with other signal molecules and the pathways forming part of signalling network that controls responses downstream of ROS.