Nitric oxide production in tobacco leaf cells: a generalized stress response?

Abstract

The function of nitric oxide (NO), a gaseous free radical emitted by many plants, is incompletely understood. In the present study the hypothesis that NO generation, like that of the reactive oxygen species, occurs as a general response to different environmental cues was tested. Leaf peels and mesophyll cell suspensions of Nicotiana tabacum cv. Xanthi were loaded with the NO-specific fluorophore, diaminofluorescein, and subjected to an abiotic stressor. Light stress and mechanical injury had no apparent effect on NO production. In contrast, high temperatures, hyperosmotic stress, salinity and epi-illumination in a microscope all led to rapid surges in NO-induced fluorescence. The fluorescence originated from cells of the palisade mesophyll and across all epidermal cell types, including guard cells, subsidiary cells, and long and short trichomes. Fluorescence was evident first in the plastids, then in the nucleus and finally throughout the cytosol. Nicotiana plumbaginifolia cell suspensions expressing the calcium reporter aequorin provided evidence that, under hyperosmotic stress, NO participates in the elevation of free Ca 2+ + + + in the cytoplasm. The physiological significance of NO production in response to abiotic stressors is discussed.

Nitric Oxide Contributes to Cadmium Toxicity in Arabidopsis by Promoting Cadmium Accumulation in Roots and by Up-Regulating Genes Related to Iron Uptake

“…In this condition, NO production was mainly detected in the stomata and the trichomes on the leaf surface (data not shown), a cell type in which Cd 2+ accumulates preferentially (Salt et al, 1995). This observation corroborates our previous data demonstrating that stomata and trichomes represent major sites for NO production in tobacco (Nicotiana tabacum) leaves exposed to several abiotic stresses, including hyperosmotic, heat, and salinity stresses (Gould et al, 2003).…”

“…As a positive control, roots of irt1 were exposed to sorbitol, an inducer of hyperosmotic stress. Sorbitol was previously shown to trigger NO synthesis both in plant cell suspensions and tissues (Gould et al, 2003;Lamotte et al, 2006). Remarkably, whereas sorbitol promoted a strong NO synthesis (Fig.…”

“…Reactive nitrogen species derived from NO oxidation nitrosate DAF-2 to yield the highly fluorescent DAF-2 triazole (DAF-2T; Kojima et al, 1998). DAF-2 and DAF-2 derivatives have been successfully used to detect NO production both in plants and animals (Kojima et al, 1998;Gould et al, 2003;Corpas et al, 2006).…”

“…NO was shown to participate in a wide spectrum of physiological pro-cesses, including germination, root growth, gravitropic bending, control of the timing of flowering, stomatal closure, and growth regulation of pollen tubes (Wilson et al, 2007;Besson-Bard et al, 2008b). Furthermore, NO has also been implicated in the plant adaptive response to biotic and abiotic stresses, notably by acting as a signaling molecule (Gould et al, 2003;Delledonne, 2005). It is becoming apparent that NO mediates its effects through S-nitrosylation of Cys residues of target proteins, modulation of protein kinase activities, and mobilization of free Ca 2+ and other second messengers, including cyclic GMP and cyclic ADP-Rib (Lamattina et al, 2003;Lindermayr et al, 2006;Romero-Puertas et al, 2007;Courtois et al, 2008).…”

Effect of nitric oxide and putrescine on antioxidative responses under NaCl stress in chickpea plants

“…NO has also been reported to act as a signal molecule; mediating responses to biotic and abiotic stresses in the plant kingdom and it appears to be present in most of the stress reactions (Gould et al, 2003). It has been reported to exert a protective effect in response to drought stress (Wang et al, 2004b), salt stress (Kopyra and Gwozdz, 2003;Zhao et al, 2004;Chen et al, 2004), heavy metal stress (Hsu and Kao, 2005;Wang and Yang, 2005) and UV radiation stress (Shi et al, 2005).…”