Elevation of Glutathione Level and Activation of Glutathione-related Enzymes Affect Virus Infection in Tobacco

Abstract

The effects of two chemicals, L-2-oxothiazolidine-4-carboxylic acid (OTC) and (S)-carvone, were investigated on the development of necrotic symptoms and on the virus concentration in tobacco mosaic virus (TMV)-infected tobacco plants. OTC treatments markedly increased the cellular glutathione (GSH) levels in tobacco leaf discs. In addition, OTC pretreatment considerably decreased both the number of necrotic lesions and the virus content in TMV-infected leaf discs. The monoterpene (S)-carvone increased only slightly the GSH content of leaf tissues and caused lipid peroxidation. (S)-carvone dramatically induced the activity of glutathione S-transferase and to a lesser extent elevated also the activities of ascorbate peroxidase and glutathione reductase. Treatments with (S)-carvone strongly reduced the number and size of necrotic lesions, but did not influence the virus concentration. The results show that increased levels of GSH and activities of GSH-related enzymes by OTC and (S)-carvone reduce necrotization of virus-infected tissues. However, virus multiplication and lesion formation do not necessarily correlate: virus multiplication is suppressed only by substantially elevated GSH contents.

Plant growth stimulation in Prunus species plantlets by BTH or OTC treatments under in vitro conditions

“…The addition of BTH or OTC has been used to prevent or reduce infection by different pathogens, including plant viruses Lawton et al, 1996;Gullner et al, 1999;Anfoka, 2000;Zechmann et al, 2007;Clemente-Moreno et al, 2010). However, all these assays were performed using herbaceous plants.…”

“…Moreover, in previous work, we described the micropropagation of healthy and PPV-infected GF305 peach plantlets for their use as a continuous source of PPV inoculums and as an interesting tool to study physiological stress over a timescale shorter than in ex vitro conditions, especially for woody plants . Several lines of evidence support the regulatory role that cellular antioxidants -especially reduced glutathione (GSH) and GSH-related enzymes -play in the biochemical and physiological responses of plants to biotic stress (Gullner et al, 1999;Fodor et al, 1997). Exposure of tobacco leaf discs to the cysteine precursor l-2-oxo-4-thiazolidine-carboxylic acid (OTC) led to a massive accumulation of GSH as well as to reduced contents of TMV coat protein and suppression of disease symptoms in TMV-inoculated tobacco plants (Gullner et al, 1999).…”

“…Several lines of evidence support the regulatory role that cellular antioxidants -especially reduced glutathione (GSH) and GSH-related enzymes -play in the biochemical and physiological responses of plants to biotic stress (Gullner et al, 1999;Fodor et al, 1997). Exposure of tobacco leaf discs to the cysteine precursor l-2-oxo-4-thiazolidine-carboxylic acid (OTC) led to a massive accumulation of GSH as well as to reduced contents of TMV coat protein and suppression of disease symptoms in TMV-inoculated tobacco plants (Gullner et al, 1999). Similarly, OTC treatment increased GSH at the subcellular level and resulted in the suppression of ZYMV-induced symptom development over a period of five weeks in pumpkin plants (Zechmann et al, 2007).…”

Oxidative stress and antioxidative responses in plant–virus interactions

“…Treatment of Xanthi-nc tobacco leaves with the synthetic GSH-precursor L-2-oxothiazolidine-4-carboxylic acid (OTC) markedly increased GSH levels. In addition, OTC pretreatment considerably decreased both the number of necrotic lesions and the virus content in TMV-infected leaf discs [62]. Also, tobacco grown with a sufficient sulphate supply displayed significantly less HR-type necrotic lesions and reduced TMV accumulation coupled with at least 50% higher GSH levels in most intracellular organelles (mitochondria, chloroplasts, nuclei, peroxisomes and cytosol) as compared to controls [81].…”

Chemical Outbreak for Tobacco Mosaic Virus Control

“…Terpenes may slightly increase cellular glutathione (GHS) levels in tobacco and have been found to lead to lipid peroxidation (Gullner et al, 1999). Further effects are related to the induction of glutathione S-transferase and to a lesser extent, also to the increased efficacy of other enzymes such as glutathione reductase or ascorbate peroxidase.…”