Reactive oxygen species and antioxidant machinery in abiotic stress tolerance in crop plants

The thioredoxin antioxidant system.

The terms 'antioxidant', 'oxidative stress' and 'oxidative damage' are widely used but rarely defined. This brief review attempts to define them and to examine the ways in which oxidative stress and oxidative damage can affect cell behaviour both in vivo and in cell culture, using cancer as an example.

Biochemistry of oxidative stress

Chloroplasts and mitochondria are the powerhouses of photosynthetic cells. The oxidation-reduction (redox) cascades of the photosynthetic and respiratory electron transport chains not only provide the driving forces for metabolism but also generate redox signals, which participate in and regulate every aspect of plant biology from gene expression and translation to enzyme chemistry. Plastoquinone, thioredoxin and reactive oxygen have all been shown to have signalling functions. Moreover, the intrinsic involvement of molecular oxygen in electron transport processes with the inherent generation of superoxide, hydrogen peroxide and singlet oxygen provides a repertoire of additional extremely powerful signals. Accumulating evidence implicates the major redox buffers of plant cells, ascorbate and glutathione, in redox signal transduction. The network of redox signals from energy-generating organelles orchestrates metabolism to adjust energy production to utilization, interfacing with hormone signalling to respond to environmental change at every stage of plant development.

https://portal.uah.es/portal/page/portal/GP_EPD/PG-MA-ASIG/PG-ASIG-65343/TAB42351/redox%20sensing%20and%20signalling.pdf

Redox sensing and signalling associated with reactive oxygen in chloroplasts, peroxisomes and mitochondria

https://www.cell.com/trends/cell-biology/pdf/S0962-8924(05)00102-9.pdf

Complex cellular responses to reactive oxygen species

Reactive oxygen species and yeast apoptosis.

Glutaredoxins are small heat-stable proteins that act as glutathione-dependent disulfide oxidoreductases. Two genes, designatedGRX1 and GRX2, which share 40–52% identity and 61–76% similarity with ...

The yeast Saccharomyces cerevisiae contains two glutaredoxin genes that are required for protection against reactive oxygen species.

Glutathione and catalase provide overlapping defenses for protection against hydrogen peroxide in the yeast Saccharomyces cerevisiae

BACKGROUND: Arsenic and cadmium are widely distributed in nature and pose serious threats to the environment and human health Exposure to these nonessential toxic metals may result in a variety of human diseases including cancer However, arsenic and cadmium toxicity targets and the cellular systems contributing to tolerance acquisition are not fully known RESULTS: To gain insight into metal action and cellular tolerance mechanisms, we carried out genome-wide screening of the Saccharomyces cerevisiae haploid and homozygous diploid deletion mutant collections and scored for reduced growth in the presence of arsenite or cadmium Processes found to be required for tolerance to both metals included sulphur and glutathione biosynthesis, environmental sensing, mRNA synthesis and transcription, and vacuolar/endosomal transport and sorting We also identified metal-specific defence processes Arsenite-specific defence functions were related to cell cycle regulation, lipid and fatty acid metabolism, mitochondrial biogenesis, and the cytoskeleton whereas cadmium-specific defence functions were mainly related to sugar/carbohydrate metabolism, and metal-ion homeostasis and transport Molecular evidence indicated that the cytoskeleton is targeted by arsenite and that phosphorylation of the Snf1p kinase is required for cadmium tolerance CONCLUSION: This study has pin-pointed core functions that protect cells from arsenite and cadmium toxicity It also emphasizes the existence of both common and specific defence systems Since many of the yeast genes that confer tolerance to these agents have homologues in humans, similar biological processes may act in yeast and humans to prevent metal toxicity and carcinogenesis

/pdf/genetic-basis-of-arsenite-and-cadmium-tolerance-in-ge003fe1au.pdf

Gabriel G. Perrone

Papers

Complex cellular responses to reactive oxygen species

Reactive oxygen species and yeast apoptosis.

The yeast Saccharomyces cerevisiae contains two glutaredoxin genes that are required for protection against reactive oxygen species.

Glutathione and catalase provide overlapping defenses for protection against hydrogen peroxide in the yeast Saccharomyces cerevisiae

Genetic basis of arsenite and cadmium tolerance in Saccharomyces cerevisiae.