The two senescence-related markers, GS1 (cytosolic glutamine synthetase) and GDH (glutamate dehydrogenase), involved in nitrogen mobilization, are differentially regulated during pathogen attack and by stress hormones and reactive oxygen species in Nicotiana tabacum L. leaves

Abstract

To investigate the role of stress in nitrogen management in plants, the effect of pathogen attack, elicitors, and phytohormone application on the expression of the two senescence-related markers GS1 (cytosolic glutamine synthetase EC 6.3.1.2) and GDH (glutamate dehydrogenase, EC 1.4.1.2) involved in nitrogen mobilization in senescing leaves of tobacco (Nicotiana tabacum L.) plants, was studied. The expression of genes involved in primary nitrogen assimilation such as GS2 (chloroplastic glutamine synthetase) and Nia (nitrate reductase, EC 1.6.1.1) was also analysed. The Glubas gene, coding a beta-1,3-glucanase, was used as a plant-defence gene control. As during natural senescence, the expression of GS2 and Nia was repressed under almost all stress conditions. By contrast, GS1 and GDH mRNA accumulation was increased. However, GS1 and GDH showed differential patterns of expression depending on the stress applied. The expression of GS1 appeared more selective than GDH. Results indicate that the GDH and GS1 genes involved in leaf senescence are also a component of the plant defence response during plant-pathogen interaction. The links between natural plant senescence and stress-induced senescence are discussed, as well as the potential role of GS1 and GDH in a metabolic safeguard process.

Amino acid changes during sunflower infection by the necrotrophic fungusB. cinerea

“…8 Glutamate dehydrogenase (GDH), a senescence-related marker, could be a component of the plant defence response during plant-pathogen interaction, related to cell death. 12 GDH transcription was activated during infection of sunflower by the necrotrophic fungus Phoma macdonadii and by fungal elicitors. 12,13 It has been suggested that GDH expression could be regarded as a cell survival process during the late phase preceding cell death.…”

“…12 GDH transcription was activated during infection of sunflower by the necrotrophic fungus Phoma macdonadii and by fungal elicitors. 12,13 It has been suggested that GDH expression could be regarded as a cell survival process during the late phase preceding cell death. 12 We analyzed, by real time Q-PCR the expression of a GDH transcript sunflower EST metabolized than other amino acids.…”

“…12,13 It has been suggested that GDH expression could be regarded as a cell survival process during the late phase preceding cell death. 12 We analyzed, by real time Q-PCR the expression of a GDH transcript sunflower EST metabolized than other amino acids. However, experiments conducted on sucrose starvation of sycamore cells revealed asparagine accumulation.…”

Comparative Studies Involving Transgenic and Non-Transgenic Soybean: What is Going On?

“…As already mentioned, the cytosolic glutamine synthetase is involved in nitrogen fixation. Oxidative stress can also control the expression of nitrogen-metabolism genes as recently demonstrated [90], demonstrating that cytosolic glutamine synthetase can be altered because of the oxidative stress observed in the transgenic soybean line [90]. …”

Functional Comparative Study of <i>Arabidopsis thaliana</i> Glutamine Synthetase gene <i>GLN1;1</i> and GLN1;5 in Response to Salt Stress during Germination

“…In previous studies, expression profiles and localization of GSs in many plant species were examined (Brugière et al, 1999(Brugière et al, , 2000Kichey et al, 2005, Lothier andGaufichon, 2009;Nord-Larsen, 2009, Peterman and Goodman, 1991, Teixeira and Fidalgo, 2009, Vance et al, 1994, and there are some studies reported the stress-resistant and nitrogen-utilization function of GS in some species (Cai et al, 2009, Fuentes et al, 2001, Habash et al, 2001, Martin et al, 2006, Jing et al, 2004, Migge et al, 2000, Oléa et al, 2004, Oliveira et al, 2002, Pageau et al, 2006, Pérez-García et al, 1998, Tavernier et al, 2007. However, specific analysis of AtGLNs is lacking of exploring expression patterns and their function in resisting salt stress during germination and seedling stage.…”