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Compartment-specific importance of glutathione during abiotic and biotic stress.

Zechmann B - Front Plant Sci (2014)

Bottom Line: Due to technical advances in the visualization of glutathione and the redox state through microscopical methods some progress was made in the last few years in studying the importance of subcellular glutathione contents during stress conditions in plants.The data will be discussed in connection with the subcellular accumulation of ROS during these conditions and glutathione synthesis which are both highly compartment specific (e.g., glutathione synthesis takes place in chloroplasts and the cytosol).Thus this review will reveal the compartment-specific importance of glutathione during abiotic and biotic stress conditions.

View Article: PubMed Central - PubMed

Affiliation: Center for Microscopy and Imaging, Baylor University , Waco, TX, USA.

ABSTRACT
The tripeptide thiol glutathione (γ-L-glutamyl-L-cysteinyl-glycine) is the most important sulfur containing antioxidant in plants and essential for plant defense against abiotic and biotic stress conditions. It is involved in the detoxification of reactive oxygen species (ROS), redox signaling, the modulation of defense gene expression, and the regulation of enzymatic activities. Even though changes in glutathione contents are well documented in plants and its roles in plant defense are well established, still too little is known about its compartment-specific importance during abiotic and biotic stress conditions. Due to technical advances in the visualization of glutathione and the redox state through microscopical methods some progress was made in the last few years in studying the importance of subcellular glutathione contents during stress conditions in plants. This review summarizes the data available on compartment-specific importance of glutathione in the protection against abiotic and biotic stress conditions such as high light stress, exposure to cadmium, drought, and pathogen attack (Pseudomonas, Botrytis, tobacco mosaic virus). The data will be discussed in connection with the subcellular accumulation of ROS during these conditions and glutathione synthesis which are both highly compartment specific (e.g., glutathione synthesis takes place in chloroplasts and the cytosol). Thus this review will reveal the compartment-specific importance of glutathione during abiotic and biotic stress conditions.

No MeSH data available.


Related in: MedlinePlus

Images show the typical distribution of glutathione. (A) Monochlorobimane staining in guard cells of the upper epidermis of tobacco cells in the light microscope. Fluorescence was observed in cytosol and nuclei (N) but not in vacuoles (V) and cell walls (arrowhead). Additionally, no fluorescence could be observed in chloroplasts (arrows in A and B) which can be best identified when comparing the autofluorescence of chloroplast (B) with monochlorobimane staining (A). Transmission electron micrographs show the subcellular distribution of glutathione (C,D) in mesophyll cells of leaves from Arabidopsis Col-0 plants. Glutathione-specific labeling could be observed in different concentrations in mitochondria (M), chloroplasts (C), peroxisomes (Px) but not in vacuoles (V) and cell walls (CW). Glutathione-specific labeling was observed in the stroma as well as inside the thylakoid lumen (arrowheads) when plants were exposed to high light intensities of 700 µmol m-2 s-1. Bars in (A,B) = 10 µm, (C,D) = 0.5 µm.
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Figure 3: Images show the typical distribution of glutathione. (A) Monochlorobimane staining in guard cells of the upper epidermis of tobacco cells in the light microscope. Fluorescence was observed in cytosol and nuclei (N) but not in vacuoles (V) and cell walls (arrowhead). Additionally, no fluorescence could be observed in chloroplasts (arrows in A and B) which can be best identified when comparing the autofluorescence of chloroplast (B) with monochlorobimane staining (A). Transmission electron micrographs show the subcellular distribution of glutathione (C,D) in mesophyll cells of leaves from Arabidopsis Col-0 plants. Glutathione-specific labeling could be observed in different concentrations in mitochondria (M), chloroplasts (C), peroxisomes (Px) but not in vacuoles (V) and cell walls (CW). Glutathione-specific labeling was observed in the stroma as well as inside the thylakoid lumen (arrowheads) when plants were exposed to high light intensities of 700 µmol m-2 s-1. Bars in (A,B) = 10 µm, (C,D) = 0.5 µm.

Mentions: With light microscopical methods after monochloro- or monobromobimane staining glutathione could be detected in nuclei and the cytosol (Fricker et al., 2000; Meyer and Fricker, 2000; Meyer et al., 2001; Müller et al., 2005). Nevertheless, light microscopical investigations which allow investigations of the in vivo situation are limited by the resolution of the light microscope (about 200 nm), by the ability of the antibodies/dyes to infiltrate the different organelles (Müller et al., 2005) and by their specificity to bind with the respective component. Monochlorobimanes, for example, bind to all thiols (not only to the reduced form of glutathione) in cells and do not infiltrate chloroplasts (Hartmann et al., 2003; Müller et al., 2005; Figures 3A,B). Additionally, monochloro- and monobromobimane are toxic to the plant and are transported into the vacuole after complexation with reduced glutathione (Fricker et al., 2000; Meyer and Fricker, 2002). This process can be inhibited by using chemicals that inhibit the transport of glutathione conjugates through the tonoplast such as sodium azide (Fricker et al., 2000). The use of redox sensitive GFP in plants has been proven to overcome some of these problems and has allowed investigations of the glutathione redox potential in vivo even in very small cell compartments with fluorescence microscopy (Meyer et al., 2007; Gutscher et al., 2008). As the signal can be targeted specifically to different cell compartments the situation can be even studied in small cell compartments such as the endoplasmic reticulum (ER) which cannot be resolved with the light microscope otherwise (Meyer et al., 2007). Additionally, this method is able to differentiate between the reduced and oxidized form of glutathione and has been used to detect changes in glutathione contents in the cytosol during environmental stress situations (Jubany-Marí et al., 2010; Lim et al., 2014). Nevertheless, in vivo investigations with confocallaser scanning or fluorescence microscopes face the problems that only very thin cell layers, tissues, or organs can be investigated and that the sample preparation (e.g., mechanical separation of the epidermis, or other tissues and cells) and investigations with the microscope (exposure to a strong light source, high temperature, lack of oxygen, water stress) can also be seen as a stress source to the sample. Single culture cells are a good alternative but similar to the above-described situation it remains unclear how the situation in single cells, cell types or tissues (e.g., epidermis) correlates with the situation in whole leaves or other tissues. Therefore the labeling results have to be carefully evaluated and the situation in single cells or tissues (e.g., epidermis) cannot always be transferred to the situation in deeper cell layers (e.g., mesophyll, vascular tissue) or the whole plant. Additionally, it was not possible so far with the above-mentioned methods to measure glutathione levels in all cell compartments simultaneously in one experiment.


Compartment-specific importance of glutathione during abiotic and biotic stress.

Zechmann B - Front Plant Sci (2014)

Images show the typical distribution of glutathione. (A) Monochlorobimane staining in guard cells of the upper epidermis of tobacco cells in the light microscope. Fluorescence was observed in cytosol and nuclei (N) but not in vacuoles (V) and cell walls (arrowhead). Additionally, no fluorescence could be observed in chloroplasts (arrows in A and B) which can be best identified when comparing the autofluorescence of chloroplast (B) with monochlorobimane staining (A). Transmission electron micrographs show the subcellular distribution of glutathione (C,D) in mesophyll cells of leaves from Arabidopsis Col-0 plants. Glutathione-specific labeling could be observed in different concentrations in mitochondria (M), chloroplasts (C), peroxisomes (Px) but not in vacuoles (V) and cell walls (CW). Glutathione-specific labeling was observed in the stroma as well as inside the thylakoid lumen (arrowheads) when plants were exposed to high light intensities of 700 µmol m-2 s-1. Bars in (A,B) = 10 µm, (C,D) = 0.5 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4202713&req=5

Figure 3: Images show the typical distribution of glutathione. (A) Monochlorobimane staining in guard cells of the upper epidermis of tobacco cells in the light microscope. Fluorescence was observed in cytosol and nuclei (N) but not in vacuoles (V) and cell walls (arrowhead). Additionally, no fluorescence could be observed in chloroplasts (arrows in A and B) which can be best identified when comparing the autofluorescence of chloroplast (B) with monochlorobimane staining (A). Transmission electron micrographs show the subcellular distribution of glutathione (C,D) in mesophyll cells of leaves from Arabidopsis Col-0 plants. Glutathione-specific labeling could be observed in different concentrations in mitochondria (M), chloroplasts (C), peroxisomes (Px) but not in vacuoles (V) and cell walls (CW). Glutathione-specific labeling was observed in the stroma as well as inside the thylakoid lumen (arrowheads) when plants were exposed to high light intensities of 700 µmol m-2 s-1. Bars in (A,B) = 10 µm, (C,D) = 0.5 µm.
Mentions: With light microscopical methods after monochloro- or monobromobimane staining glutathione could be detected in nuclei and the cytosol (Fricker et al., 2000; Meyer and Fricker, 2000; Meyer et al., 2001; Müller et al., 2005). Nevertheless, light microscopical investigations which allow investigations of the in vivo situation are limited by the resolution of the light microscope (about 200 nm), by the ability of the antibodies/dyes to infiltrate the different organelles (Müller et al., 2005) and by their specificity to bind with the respective component. Monochlorobimanes, for example, bind to all thiols (not only to the reduced form of glutathione) in cells and do not infiltrate chloroplasts (Hartmann et al., 2003; Müller et al., 2005; Figures 3A,B). Additionally, monochloro- and monobromobimane are toxic to the plant and are transported into the vacuole after complexation with reduced glutathione (Fricker et al., 2000; Meyer and Fricker, 2002). This process can be inhibited by using chemicals that inhibit the transport of glutathione conjugates through the tonoplast such as sodium azide (Fricker et al., 2000). The use of redox sensitive GFP in plants has been proven to overcome some of these problems and has allowed investigations of the glutathione redox potential in vivo even in very small cell compartments with fluorescence microscopy (Meyer et al., 2007; Gutscher et al., 2008). As the signal can be targeted specifically to different cell compartments the situation can be even studied in small cell compartments such as the endoplasmic reticulum (ER) which cannot be resolved with the light microscope otherwise (Meyer et al., 2007). Additionally, this method is able to differentiate between the reduced and oxidized form of glutathione and has been used to detect changes in glutathione contents in the cytosol during environmental stress situations (Jubany-Marí et al., 2010; Lim et al., 2014). Nevertheless, in vivo investigations with confocallaser scanning or fluorescence microscopes face the problems that only very thin cell layers, tissues, or organs can be investigated and that the sample preparation (e.g., mechanical separation of the epidermis, or other tissues and cells) and investigations with the microscope (exposure to a strong light source, high temperature, lack of oxygen, water stress) can also be seen as a stress source to the sample. Single culture cells are a good alternative but similar to the above-described situation it remains unclear how the situation in single cells, cell types or tissues (e.g., epidermis) correlates with the situation in whole leaves or other tissues. Therefore the labeling results have to be carefully evaluated and the situation in single cells or tissues (e.g., epidermis) cannot always be transferred to the situation in deeper cell layers (e.g., mesophyll, vascular tissue) or the whole plant. Additionally, it was not possible so far with the above-mentioned methods to measure glutathione levels in all cell compartments simultaneously in one experiment.

Bottom Line: Due to technical advances in the visualization of glutathione and the redox state through microscopical methods some progress was made in the last few years in studying the importance of subcellular glutathione contents during stress conditions in plants.The data will be discussed in connection with the subcellular accumulation of ROS during these conditions and glutathione synthesis which are both highly compartment specific (e.g., glutathione synthesis takes place in chloroplasts and the cytosol).Thus this review will reveal the compartment-specific importance of glutathione during abiotic and biotic stress conditions.

View Article: PubMed Central - PubMed

Affiliation: Center for Microscopy and Imaging, Baylor University , Waco, TX, USA.

ABSTRACT
The tripeptide thiol glutathione (γ-L-glutamyl-L-cysteinyl-glycine) is the most important sulfur containing antioxidant in plants and essential for plant defense against abiotic and biotic stress conditions. It is involved in the detoxification of reactive oxygen species (ROS), redox signaling, the modulation of defense gene expression, and the regulation of enzymatic activities. Even though changes in glutathione contents are well documented in plants and its roles in plant defense are well established, still too little is known about its compartment-specific importance during abiotic and biotic stress conditions. Due to technical advances in the visualization of glutathione and the redox state through microscopical methods some progress was made in the last few years in studying the importance of subcellular glutathione contents during stress conditions in plants. This review summarizes the data available on compartment-specific importance of glutathione in the protection against abiotic and biotic stress conditions such as high light stress, exposure to cadmium, drought, and pathogen attack (Pseudomonas, Botrytis, tobacco mosaic virus). The data will be discussed in connection with the subcellular accumulation of ROS during these conditions and glutathione synthesis which are both highly compartment specific (e.g., glutathione synthesis takes place in chloroplasts and the cytosol). Thus this review will reveal the compartment-specific importance of glutathione during abiotic and biotic stress conditions.

No MeSH data available.


Related in: MedlinePlus