Selenite activates the alternative oxidase pathway and alters primary metabolism in Brassica napus roots: evidence of a mitochondrial stress response
| Autor: | Doug Van Hoewyk, Aleksandar Dimkovikj |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
Alternative oxidase
Antioxidant γ-glutamyl cyclotransferase medicine.medical_treatment Cell Respiration chemistry.chemical_element Plant Science Biology Pentose phosphate pathway medicine.disease_cause Selenious Acid Plant Roots Mitochondrial Proteins Pentose Phosphate Pathway chemistry.chemical_compound Selenium Stress Physiological Superoxides medicine TCA cycle Plant Proteins Aconitate Hydratase Brassica napus food and beverages Glutathione Metabolism Mitochondria Metabolic pathway chemistry Biochemistry Oxidoreductases Oxidative stress Mitochondrial superoxide Research Article |
| Zdroj: | BMC Plant Biology |
| ISSN: | 1471-2229 |
| Popis: | Background Human requirements for dietary selenium are met mainly by crops. However, excessive uptake of selenium in plants can restrict growth, and its toxicity has been postulated to target roots. Selenite toxicity can be attributed to its assimilation into selenocysteine, which can replace cysteine to yield malformed selenoproteins. Additionally, selenite has pro-oxidant properties. In this study, the effects of selenite on root tissue in Brassica napus (canola) were investigated to better understand its mode of toxicity and the metabolic adjustments needed to mediate a selenite-response. Results Selenite induced the rapid formation of mitochondrial superoxide, which led to decreased aconitase activity and involvement of the alternative oxidase pathway. Although selenite altered primary metabolism, as observed by the increased amino acids and decreased TCA cycle metabolites, increased glucose presumably supported higher respiratory rates and ATP levels reported in this study. Additionally, evidence is presented indicating that selenite suppressed the ubiquitin-proteasome pathway, and induced the pentose phosphate pathway needed to maintain antioxidant metabolism. Selenite treatment also elevated glutathione concentration and coincided with increased levels of γ-glutamyl cyclotransferase, which may possibly degrade selenium metabolites conjugated to glutathione. Conclusion Collectively, the data indicate that selenite necessitates the reconfiguration of metabolic pathways to overcome the consequences of mitochondrial oxidative stress in root tissue. Efforts to mitigate the detrimental effects of selenite-induced oxidative stress may ultimately improve selenium tolerance and accumulation in crops. Electronic supplementary material The online version of this article (doi:10.1186/s12870-014-0259-6) contains supplementary material, which is available to authorized users. |
| Databáze: | OpenAIRE |
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