Gene expression and mucilage adaptations to salinity in germination of extreme halophyte Schrenkiella parvula seeds.

Salinization is a significant global issue causes irreversible damage to plants by reducing osmotic potential, inhibiting seed germination, and impeding water uptake. Seed germination, a crucial step towards the seedling stage is regulated by several hormones and genes, with the balance between abscisic acid and gibberellin being the key mechanism that either promotes or inhibits this process. Additionally, mucilage, a gelatinous substance, is known to provide protection against drought, herbivory, soil adhesion, and seed sinking.

Alternative electron sinks in chloroplasts and mitochondria of halophytes as a safety valve for controlling ROS production during salinity.

Electron flow through the electron transport chain (ETC) is essential for oxidative phosphorylation in mitochondria and photosynthesis in chloroplasts. Electron fluxes depend on environmental parameters, e.g.

Differential regulation of reactive oxygen species in dimorphic chloroplasts of single cell C plant during drought and salt stress.

Single cell C (SCC) plants, discovered around two decades ago, are promising materials for efforts for genetic engineering of C photosynthesis into C crops. Unlike C plants with Kranz anatomy, they exhibit a fully functional C photosynthesis in just a single cell and do not require mesophyll and bundle sheath cell spatial separation. is one such SCC plant, with NAD-malic enzyme (NAD-ME) subtype C photosynthesis.

Differential responses of the scavenging systems for reactive oxygen species (ROS) and reactive carbonyl species (RCS) to UV-B irradiation in Arabidopsis thaliana and its high altitude perennial relative Arabis alpina.

The present work aimed to compare antioxidant response and lipid peroxide detoxification capacity of an arctic-alpine species Arabis alpina to its close relative model species Arabidopsis thaliana under acute short duration (3 h and 6 h) UV-B stress (4.6 and 8.2 W/m).

Melatonin mitigates UV-B stress via regulating oxidative stress response, cellular redox and alternative electron sinks in Arabidopsis thaliana.

Melatonin plays an active role in neutralizing free radicals, especially by triggering the defense system and certain enzymes that work under stress in both mammals and plant systems. Exposure to ultraviolet (UV-B) stress can be deadly for plants since UV-B can induce production of reactive oxygen species and damage nucleic acids. In the present study, to uncover the possible alleviative role of melatonin against UV-B stress, Arabidopsis thaliana plants were treated with melatonin (10 μM) and were exposed to UV-B stress for 90 min and 180 min (46 and 92 kJ m d).

The involvement of gamma-aminobutyric acid shunt in the endoplasmic reticulum stress response of Arabidopsis thaliana.

The endoplasmic reticulum (ER) is the main site of secretory protein production and folding and its homeostasis under environmental stress is vital for the maintenance of the protein secretory pathway. The loss of homeostasis and accumulation of unfolded proteins in the ER is referred to as ER stress. Although, γ-aminobutyric acid (GABA) is an important regulator of stress response in plants, its roles during ER stress remains unclear.

Understanding the Role of the Antioxidant System and the Tetrapyrrole Cycle in Iron Deficiency Chlorosis.

Iron deficiency chlorosis (IDC) is an abiotic stress often experienced by soybean, owing to the low solubility of iron in alkaline soils. Here, soybean lines with contrasting Fe efficiencies were analyzed to test the hypothesis that the Fe efficiency trait is linked to antioxidative stress signaling via proper management of tissue Fe accumulation and transport, which in turn influences the regulation of heme and non heme containing enzymes involved in Fe uptake and ROS scavenging. Inefficient plants displayed higher oxidative stress and lower ferric reductase activity, whereas root and leaf catalase activity were nine-fold and three-fold higher, respectively.

Reactive oxygen species and redox regulation in mesophyll and bundle sheath cells of C4 plants.

Redox regulation, antioxidant defence, and reactive oxygen species (ROS) signalling are critical in performing and tuning metabolic activities. However, our concepts have mostly been developed for C3 plants since Arabidopsis thaliana has been the major model for research. Efforts to convert C3 plants to C4 to increase yield (such as IRRI's C4 Rice Project) entail a better understanding of these processes in C4 plants.

Interplay between the unfolded protein response and reactive oxygen species: a dynamic duo.

Secretory proteins undergo modifications such as glycosylation and disulphide bond formation before proper folding, and move to their final destination via the endomembrane system. Accumulation of unfolded proteins in the endoplasmic reticulum (ER) due to suboptimal environmental conditions triggers a response called the unfolded protein response (UPR), which induces a set of genes that elevate protein folding capacity in the ER. This review aims to establish a connection among ER stress, UPR, and reactive oxygen species (ROS), which remains an unexplored topic in plants.

Endoplasmic reticulum stress regulates glutathione metabolism and activities of glutathione related enzymes in Arabidopsis.

Stress conditions generate an extra load on protein folding machinery in the endoplasmic reticulum (ER) and if the ER cannot overcome this load, unfolded proteins accumulate in the ER lumen, causing ER stress. ER lumen localised protein disulfide isomerase (PDI) catalyses the generation of disulfide bonds in conjugation with ER oxidoreductase1 (ERO1) during protein folding. Mismatched disulfide bonds are reduced by the conversion of GSH to GSSG.

Changes in redox regulation during transition from C to single cell C photosynthesis in Bienertia sinuspersici.

Bienertia sinuspersici performs single cell C photosynthesis without Kranz anatomy. Peripheral and central cytoplasmic compartments in a single chlorenchyma cell act as mesophyll cells and bundle sheath cells. Development of this specialized mechanism is gradual during plant development.

NAC transcription factor JUNGBRUNNEN1 enhances drought tolerance in tomato.

Water deficit (drought stress) massively restricts plant growth and the yield of crops; reducing the deleterious effects of drought is therefore of high agricultural relevance. Drought triggers diverse cellular processes including the inhibition of photosynthesis, the accumulation of cell-damaging reactive oxygen species and gene expression reprogramming, besides others. Transcription factors (TF) are central regulators of transcriptional reprogramming and expression of many TF genes is affected by drought, including members of the NAC family.

Halophytes as a source of salt tolerance genes and mechanisms: a case study for the Salt Lake area, Turkey.

The worst case scenario of global climate change predicts both drought and salinity would be the first environmental factors restricting agriculture and natural ecosystems, causing decreased crop yields and plant growth that would directly affect human population in the next decades. Therefore, it is vital to understand the biology of plants that are already adapted to these extreme conditions. In this sense, extremophiles such as the halophytes offer valuable genetic information for understanding plant salinity tolerance and to improve the stress tolerance of crop plants.

The effects of induced production of reactive oxygen species in organelles on endoplasmic reticulum stress and on the unfolded protein response in arabidopsis.

Background And Aims: Accumulation of unfolded proteins caused by inefficient chaperone activity in the endoplasmic reticulum (ER) is termed 'ER stress', and it is perceived by a complex gene network. Induction of these genes triggers a response termed the 'unfolded protein response' (UPR). If a cell cannot overcome the accumulation of unfolded proteins, the ER-associated degradation (ERAD) system is induced to degrade those proteins.

Preferential expression of a bromoperoxidase in sporophytes of a red alga, Pyropia yezoensis.

A 2,158 bp cDNA (PyBPO1) encoding a bromoperoxidase (BPO) of 625 amino acids was isolated from Pyropia yezoensis. Phylogenetic analysis using amino acid sequences of BPOs suggested that P. yezoensis and cyanobacteria were grouped in the same clade and separated from brown algae.

Changes in the alternative electron sinks and antioxidant defence in chloroplasts of the extreme halophyte Eutrema parvulum (Thellungiella parvula) under salinity.

Background And Aims: Eutrema parvulum (synonym, Thellungiella parvula) is an extreme halophyte that thrives in high salt concentrations (100-150 mm) and is closely related to Arabidopsis thaliana. The main aim of this study was to determine how E. parvulum uses reactive oxygen species (ROS) production, antioxidant systems and redox regulation of the electron transport system in chloroplasts to tolerate salinity.

Endoplasmic reticulum stress triggers ROS signalling, changes the redox state, and regulates the antioxidant defence of Arabidopsis thaliana.

Inefficient chaperone activity in endoplasmic reticulum (ER) causes accumulation of unfolded proteins and is called ER stress, which triggers the unfolded protein response. For proper oxidative protein folding, reactive oxygen species (ROS) such as H2O2 are produced in the ER. Although the role of ROS during abiotic stresses such as salinity is well documented, the role of ER-related ROS production and its signalling is not yet known.

Strategies of ROS regulation and antioxidant defense during transition from C₃ to C₄ photosynthesis in the genus Flaveria under PEG-induced osmotic stress.

In the present study, we aimed to elucidate how strategies of reactive oxygen species (ROS) regulation and the antioxidant defense system changed during transition from C₃ to C₄ photosynthesis, by using the model genus Flaveria, which contains species belonging to different steps in C₄ evolution. For this reason, four Flaveria species that have different carboxylation mechanisms, Flaveria robusta (C₃), Flaveria anomala (C₃-C₄), Flaveria brownii (C₄-like) and Flaveria bidentis (C₄), were used. Physiological (growth, relative water content (RWC), osmotic potential), and photosynthetical parameters (stomatal conductance (g(s)), assimilation rate (A), electron transport rate (ETR)), antioxidant defense enzymes (superoxide dismutase (SOD), catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX), glutathione reductases(GR)) and their isoenzymes, non-enzymatic antioxidant contents (ascorbate, glutathione), NADPH oxidase (NOX) activity, hydrogen peroxide (H₂O₂) content and lipid peroxidation levels (TBARS) were measured comparatively under polyethylene glycol (PEG 6000) induced osmotic stress.

Reactive oxygen species regulation and antioxidant defence in halophytes.

Production of reactive oxygen species (ROS), which are a by-product of normal cell metabolism in living organisms, is an inevitable consequence of aerobic life on Earth, and halophytes are no exception to this rule. The accumulation of ROS is elevated under different stress conditions, including salinity, due to a serious imbalance between their production and elimination. These ROS are highly toxic and, in the absence of protective mechanisms, can cause oxidative damage to lipids, proteins and DNA, leading to alterations in the redox state and further damage to the cell.