Regulation of Sulfate Assimilation in Arabidopsis and Beyond

Kopriva, Stanislav

doi:10.1093/aob/mcl006

Cited by 276 publications

(241 citation statements)

References 202 publications

(289 reference statements)

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“…Considering the expression of the sulfite network components and sulfur-containing metabolites in SIR Ri tomato plants, our results indicate that SiR impairment results in a thiol shortage that activates the sulfate reduction pathway, including APR-generated sulfite (Leustek et al, 2000;Kopriva and Rennenberg, 2004;Kopriva, 2006). In the absence of normal SiR activity, the other sulfite-converting components of the sulfite network are activated for maintaining homeostatic sulfite levels in the plant tissues.…”

Section: Sulfite Homeostasis In Sir-impaired Tomato Plantsmentioning

confidence: 86%

“…APR is known to be regulated by a number of factors such as diurnal rhythm (Kopriva et al, 1999), nitrogen deficiency , and carbohydrate (Hesse et al, 2003) and salinity levels (Koprivova et al, 2008). Importantly, APR is highly regulated by thiols in a demand-driven manner (Leustek et al, 2000;Kopriva and Rennenberg, 2004;Kopriva, 2006), i.e. its activity increases when reduced sulfur compounds levels are low, such as during sulfur starvation or depletion of glutathione, and decreases when excess reduced sulfur is available (Vauclare et al, 2002; .…”

Section: Sulfite Homeostasis In Sir-impaired Tomato Plantsmentioning

confidence: 99%

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Impairment in Sulfite Reductase Leads to Early Leaf Senescence in Tomato Plants

et al. 2014

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Sulfite reductase (SiR) is an essential enzyme of the sulfate assimilation reductive pathway, which catalyzes the reduction of sulfite to sulfide. Here, we show that tomato (Solanum lycopersicum) plants with impaired SiR expression due to RNA interference (SIR Ri) developed early leaf senescence. The visual chlorophyll degradation in leaves of SIR Ri mutants was accompanied by a reduction of maximal quantum yield, as well as accumulation of hydrogen peroxide and malondialdehyde, a product of lipid peroxidation. Interestingly, messenger RNA transcripts and proteins involved in chlorophyll breakdown in the chloroplasts were found to be enhanced in the mutants, while transcripts and their plastidic proteins, functioning in photosystem II, were reduced in these mutants compared with wild-type leaves. As a consequence of SiR impairment, the levels of sulfite, sulfate, and thiosulfate were higher and glutathione levels were lower compared with the wild type. Unexpectedly, in a futile attempt to compensate for the low glutathione, the activity of adenosine-59-phosphosulfate reductase was enhanced, leading to further sulfite accumulation in SIR Ri plants. Increased sulfite oxidation to sulfate and incorporation of sulfite into sulfoquinovosyl diacylglycerols were not sufficient to maintain low basal sulfite levels, resulting in accumulative leaf damage in mutant leaves. Our results indicate that, in addition to its biosynthetic role, SiR plays an important role in prevention of premature senescence. The higher sulfite is likely the main reason for the initiation of chlorophyll degradation, while the lower glutathione as well as the higher hydrogen peroxide and malondialdehyde additionally contribute to premature senescence in mutant leaves.

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Section: Sulfite Homeostasis In Sir-impaired Tomato Plantsmentioning

confidence: 86%

Section: Sulfite Homeostasis In Sir-impaired Tomato Plantsmentioning

confidence: 99%

Impairment in Sulfite Reductase Leads to Early Leaf Senescence in Tomato Plants

et al. 2014

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“…We hypothesize that CGN-associated sulfate groups become part of the human intestinal epithelial cell's electron acceptor pool and disrupt the normal redox balance. The sulfate assimilation pathway in plants, yeast, and protists provides a prototype for a series of reactions that reduce sulfate groups and metabolize sulfate so that it can be re-utilized in sulfotransferase reactions [39][40][41][42][43][44][45].…”

Section: Discussionmentioning

confidence: 99%

Carrageenan-induced NFκB activation depends on distinct pathways mediated by reactive oxygen species and Hsp27 or by Bcl10

Bhattacharyya

Dudeja

Tobacman

2008

Biochimica et Biophysica Acta (BBA) - General Subjects

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Carrageenans are highly sulfated polysaccharides that are widely used as food additives due to their ability to improve food texture. They are also widely recognized for their ability to induce inflammation in animal models of colitis. Recently, we reported that carrageenan (CGN) activated a pathway of innate immunity in human colonic epithelial cells mediated by Bcl10 (B-cell CLL/ lymphoma 10). However, increases in phospho-IκBα and Interleukin-8 (IL-8) were not completely inhibited by silencing Bcl10, suggesting that CGN also influenced another mechanism, or mechanisms, of inflammation. In this report, we demonstrate that CGN increases production of reactive oxygen species (ROS) in human colonic epithelial cells. The combination of ROS quenching by the free radical scavenger Tempol and of Bcl10 silencing by siRNA completely inhibited the CGN-induced increases in nuclear NFκB (p65), phospho-IκBα, and secretion of IL-8. The CGN-induced increase in ROS was associated with declines in phosphorylation of MAPK 12 (p38γ), MAPK 13 (p38δ), and heat-shock protein (Hsp) 27. The CGN-induced decline in phospho-Hsp27 was reversed by co-administration of Tempol (100nM), but unaffected by silencing Bcl10. Since Hsp27 phosphorylation is inversely associated with phosphorylation of the IκBα kinase (IKK) signalosome, CGN exposure appears to affect the IKK signalosome by both the catalytic component, mediated by ROS-phospho-Hsp27, and the regulatory component, mediated by Bcl10 interaction with IKKγ (Nemo). Hence, the CGN-activated inflammatory cascades related to innate immunity and to generation of ROS may be integrated at the level of the IKK signalosome.

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“…4A). Since Cys is also used as the precursor for the synthesis of glutathione (GSH) and the level of GSH is limited by Cys content (Kopriva, 2006), the level of GSH was also determined. Similarly to Cys, the levels of GSH were reduced significantly by 12% in SSE 1 and by 16% in SSE 2 (Fig.…”

Section: Transgenic Seeds Expressing Atd-cgs Accumulate Higher Levelsmentioning

confidence: 99%

Seed-Specific Expression of a Feedback-Insensitive Form of CYSTATHIONINE-γ-SYNTHASE in Arabidopsis Stimulates Metabolic and Transcriptomic Responses Associated with Desiccation Stress

et al. 2014

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and Tel-Hai College, Upper Galilee 11016, Israel (R.A.) With an aim to elucidate novel metabolic and transcriptional interactions associated with methionine (Met) metabolism in seeds, we have produced transgenic Arabidopsis (Arabidopsis thaliana) seeds expressing a feedback-insensitive form of CYSTATHIONINEg-SYNTHASE, a key enzyme of Met synthesis. Metabolic profiling of these seeds revealed that, in addition to higher levels of Met, the levels of many other amino acids were elevated. The most pronounced changes were the higher levels of stress-related amino acids (isoleucine, leucine, valine, and proline), sugars, intermediates of the tricarboxylic acid cycle, and polyamines and lower levels of polyols, cysteine, and glutathione. These changes reflect stress responses and an altered mitochondrial energy metabolism. The transgenic seeds also had higher contents of total proteins and starch but lower water contents. In accordance with the metabolic profiles, microarray analysis identified a strong induction of genes involved in defense mechanisms against osmotic and drought conditions, including those mediated by the signaling cascades of ethylene and abscisic acid. These changes imply that stronger desiccation processes occur during seed development. The expression levels of transcripts controlling the levels of Met, sugars, and tricarboxylic acid cycle metabolites were also significantly elevated. Germination assays showed that the transgenic seeds had higher germination rates under salt and osmotic stresses and in the presence of ethylene substrate and abscisic acid. However, under oxidative conditions, the transgenic seeds displayed much lower germination rates. Altogether, the data provide new insights on the factors regulating Met metabolism in Arabidopsis seeds and on the mechanisms by which elevated Met levels affect seed composition and behavior.

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Regulation of Sulfate Assimilation in Arabidopsis and Beyond

Cited by 276 publications

References 202 publications

Impairment in Sulfite Reductase Leads to Early Leaf Senescence in Tomato Plants

Impairment in Sulfite Reductase Leads to Early Leaf Senescence in Tomato Plants

Carrageenan-induced NFκB activation depends on distinct pathways mediated by reactive oxygen species and Hsp27 or by Bcl10

Seed-Specific Expression of a Feedback-Insensitive Form of CYSTATHIONINE-γ-SYNTHASE in Arabidopsis Stimulates Metabolic and Transcriptomic Responses Associated with Desiccation Stress

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