Spatial and temporal regulation of the metabolism of reactive oxygen and nitrogen species during the early development of pepper (Capsicum annuum) seedlings

Background and Aims The development of seedlings involves many morphological, physiological and biochemical processes, which are controlled by many factors. Some reactive oxygen and nitrogen species (ROS and RNS, respectively) are implicated as signal molecules in physiological and phytopathological processes. Pepper (Capsicum annuum) is a very important crop and the goal of this work was to provide a framework of the behaviour of the key elements in the metabolism of ROS and RNS in the main organs of pepper during its development.Methods The main seedling organs (roots, hypocotyls and green cotyledons) of pepper seedlings were analysed 7, 10 and 14 d after germination. Activity and gene expression of the main enzymatic antioxidants (catalase, ascorbate–glutathione cycle enzymes), NADP-generating dehydrogenases and S-nitrosoglutathione reductase were determined. Cellular distribution of nitric oxide (^·NO), superoxide radical (O₂^·–) and peroxynitrite (ONOO^–) was investigated using confocal laser scanning microscopy.Key Results The metabolism of ROS and RNS during pepper seedling development was highly regulated and showed significant plasticity, which was co-ordinated among the main seedling organs, resulting in correct development. Catalase showed higher activity in the aerial parts of the seedling (hypocotyls and green cotyledons) whereas roots of 7-d-old seedlings contained higher activity of the enzymatic components of the ascorbate glutathione cycle, NADP-isocitrate dehydrogenase and NADP-malic enzyme.Conclusions There is differential regulation of the metabolism of ROS, nitric oxide and NADP dehydrogenases in the different plant organs during seedling development in pepper in the absence of stress. The metabolism of ROS and RNS seems to contribute significantly to plant development since their components are involved directly or indirectly in many metabolic pathways. Thus, specific molecules such as H₂O₂ and NO have implications for signalling, and their temporal and spatial regulation contributes to the success of seedling establishment.     

Host Suitability of Rapeseed for Heterodera schachtii

Because rapeseed, especially canola, has the potential to be grown in rotation with sugarbeet in the north-central region of the United States, this study was initiated to assess its susceptibility to infection by Heterodera schachtii and to develop a screening method for Brassica germplasm. Existing methodology was adapted for growing Brassica juncea, B. napus, B. rapa, Brassica hybrids, and sugarbeet, Beta vulgaris, in H. schachtii-infested soil to count the females that developed on the roots. Cysts on sugarbeet contained a mean of 130 eggs compared with 240 for B. napus, lowest for the Brassica. Viability of eggs produced was assessed in soil planted with Brassica and sugarbeet and infested with with 0, 100, 1,000, 3,000, and 5,000 eggs to count resulting females and cysts. Number of females (y) was related linearly to infestation rate (x) by the regression equations y = 2.82 + 0.07(x) for the Brassica lines (R² = 0.79; P < 0.001) and y = 0.43 + 0.04(x) for sugarbeet (R² = 0.69; P < 0.007). These data indicated the potential for H. schachtii population increase if the two crops are used in rotation. All of the 111 germplasm lines tested were susceptible. The methodology developed during this research would benefit attempts to develop rapeseed cultivars resistant to H. schachtii.     

Peroxisomes sense and respond to environmental cues by regulating ROS and RNS signalling networks

Background Peroxisomes are highly dynamic, metabolically active organelles that used to be regarded as a sink for H₂O₂ generated in different organelles. However, peroxisomes are now considered to have a more complex function, containing different metabolic pathways, and they are an important source of reactive oxygen species (ROS), nitric oxide (NO) and reactive nitrogen species (RNS). Over-accumulation of ROS and RNS can give rise oxidative and nitrosative stress, but when produced at low concentrations they can act as signalling molecules.Scope This review focuses on the production of ROS and RNS in peroxisomes and their regulation by antioxidants. ROS production is associated with metabolic pathways such as photorespiration and fatty acid β-oxidation, and disturbances in any of these processes can be perceived by the cell as an alarm that triggers defence responses. Genetic and pharmacological studies have shown that photorespiratory H₂O₂ can affect nuclear gene expression, regulating the response to pathogen infection and light intensity. Proteomic studies have shown that peroxisomal proteins are targets for oxidative modification, S-nitrosylation and nitration and have highlighted the importance of these modifications in regulating peroxisomal metabolism and signalling networks. The morphology, size, number and speed of movement of peroxisomes can also change in response to oxidative stress, meaning that an ROS/redox receptor is required. Information available on the production and detection of NO/RNS in peroxisomes is more limited. Peroxisomal homeostasis is critical for maintaining the cellular redox balance and is regulated by ROS, peroxisomal proteases and autophagic processes.Conclusions Peroxisomes play a key role in many aspects of plant development and acclimation to stress conditions. These organelles can sense ROS/redox changes in the cell and thus trigger rapid and specific responses to environmental cues involving changes in peroxisomal dynamics as well as ROS- and NO-dependent signalling networks, although the mechanisms involved have not yet been established. Peroxisomes can therefore be regarded as a highly important decision-making platform in the cell, where ROS and RNS play a determining role.     

Antioxidant defense system in leaves of Indian mustard (<Emphasis Type="Italic">Brassica juncea</Emphasis>) and rape (<Emphasis Type="Italic">Brassica napus</Emphasis>) under cadmium stress

Plant species capable of hyper-accumulating heavy metals are of considerable interest for phytoremediation, and differ in their ability to accumulate metals from environment. Using two brassica species (Brassica juncea and Brassica napus), nutrient solution experiments were conducted to study variation in tolerance to cadmium (Cd) toxicity based on (1) lipid peroxidation and (2) changes in antioxidative defense system in leaves of both plants (i.e., superoxide dismutase (SOD EC 1.15.1.1), catalase (CAT EC 1.11.1.6), ascorbate peroxidase (APX EC 1.11.1.11), guaiacol peroxidase (GPX EC 1.11.1.7), glutathione reductase (GR EC 1.6.4.2), levels of phytochelatins (PCs), non-protein thiols (NP-SH), and glutathione. Plants were grown in nutrient solution under controlled environmental conditions, and subjected to increasing concentrations of Cd (0, 10, 25 and 50 μM) for 15 days. Results showed marked differences between both species. Brassica napus under Cd stress exhibited increased level of lipid peroxidation, as was evidenced by the increased malondialdehyde (MDA) content in leaves. However, in Brassica juncea treated plants, MDA content remained unchanged. In Brassica napus, with the exception of GPX, activity levels of some antioxidant enzymes involved in detoxification of reactive oxygen species (ROS), including SOD, CAT, GR, and APX, decreased drastically at high Cd concentrations. By contrast, in leaves of Brassica juncea treated plants, there was either only slight or no change in the activities of the antioxidative enzymes. Analysis of the profile of anionic isoenzymes of GPX revealed qualitative changes occurring during Cd exposure for both species. Moreover, levels of NP-SH and PCs, monitored as metal detoxifying responses, were much increased in leaves of Brassica juncea by increasing Cd supply, but did not change in Brassica napus. These results indicate that Brassica juncea plants possess the greater potential for Cd accumulation and tolerance than Brassica napus.     

Oxidative and nitrosative signaling in plants: Two branches in the same tree?

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) constitute key features underpinning the dynamic nature of cell signaling systems in plants. Despite their importance in many aspects of cell biology, our understanding of oxidative and especially of nitrosative signaling and their regulation remains poorly understood. Early reports have established that ROS and RNS coordinately regulate plant defense responses to biotic stress. In addition, evidence has accumulated demonstrating that there is a strong cross-talk between oxidative and nitrosative signaling upon abiotic stress conditions. The goal of this mini-review is to provide latest findings showing how both ROS and RNS comprise a coordinated oxidative and nitrosative signaling network that modulates cellular responses in response to environmental stimuli.Key words: abiotic stress, nitrosative stress, oxidative stress, reactive nitrogen species, reactive oxygen species, signaling     

Developmental stage- and concentration-specific sodium nitroprusside application results in nitrate reductase regulation and the modification of nitrate metabolism in leaves of Medicago truncatula plants

Nitric oxide (NO) is a bioactive molecule involved in numerous biological events that has been reported to display both pro-oxidant and antioxidant properties in plants. Several reports exist which demonstrate the protective action of sodium nitroprusside (SNP), a widely used NO donor, which acts as a signal molecule in plants responsible for the expression regulation of many antioxidant enzymes. This study attempts to provide a novel insight into the effect of application of low (100 μΜ) and high (2.5 mM) concentrations of SNP on the nitrosative status and nitrate metabolism of mature (40 d) and senescing (65 d) Medicago truncatula plants. Higher concentrations of SNP resulted in increased NO content, cellular damage levels and reactive oxygen species (ROS) concentration, further induced in older tissues. Senescing M. truncatula plants demonstrated greater sensitivity to SNP-induced oxidative and nitrosative damage, suggesting a developmental stage-dependent suppression in the plant’s capacity to cope with free oxygen and nitrogen radicals. In addition, measurements of the activity of nitrate reductase (NR), a key enzyme involved in the generation of NO in plants, indicated a differential regulation in a dose and time-dependent manner. Furthermore, expression levels of NO-responsive genes (NR, nitrate/nitrite transporters) involved in nitrogen assimilation and NO production revealed significant induction of NR and nitrate transporter during long-term 2.5 mM SNP application in mature plants and overall gene suppression in senescing plants, supporting the differential nitrosative response of M. truncatula plants treated with different concentrations of SNP.     

A triallelic genetic male sterility locus in Brassica napus: an integrative strategy for its physical mapping and possible local chromosome evolution around it

Background and Aims

Spontaneous male sterility is an advantageous trait for both constructing efficient pollination control systems and for understanding the developmental process of the male reproductive unit in many crops. A triallelic genetic male-sterile locus (BnMs5) has been identified in Brassica napus; however, its complicated genome structure has greatly hampered the isolation of this locus. The aim of this study was to physically map BnMs5 through an integrated map-based cloning strategy and analyse the local chromosomal evolution around BnMs5.

Methods

A large F₂ population was used to integrate the existing genetic maps around BnMs5. A map-based cloning strategy in combination with comparative mapping among B. napus, Arabidopsis, Brassica rapa and Brassica oleracea was employed to facilitate the identification of a target bacterial artificial chromosome (BAC) clone covering the BnMs5 locus. The genomic sequences from the Brassica species were analysed to reveal the regional chromosomal evolution around BnMs5.

Key Results

BnMs5 was finally delimited to a 0·3-cM genetic fragment from an integrated local genetic map, and was anchored on the B. napus A8 chromosome. Screening of a B. napus BAC clone library and identification of the positive clones validated that JBnB034L06 was the target BAC clone. The closest flanking markers restrict BnMs5 to a 21-kb region on JBnB034L06 containing six predicted functional genes. Good collinearity relationship around BnMs5 between several Brassica species was observed, while violent chromosomal evolutionary events including insertions/deletions, duplications and single nucleotide mutations were also found to have extensively occurred during their divergence.

Conclusions

This work represents major progress towards the molecular cloning of BnMs5, as well as presenting a powerful, integrative method to mapping loci in plants with complex genomic architecture, such as the amphidiploid B. napus.     

Analysis of Oxidative Stress in Zebrafish Embryos

High levels of reactive oxygen species (ROS) may cause a change of cellular redox state towards oxidative stress condition. This situation causes oxidation of molecules (lipid, DNA, protein) and leads to cell death. Oxidative stress also impacts the progression of several pathological conditions such as diabetes, retinopathies, neurodegeneration, and cancer. Thus, it is important to define tools to investigate oxidative stress conditions not only at the level of single cells but also in the context of whole organisms. Here, we consider the zebrafish embryo as a useful in vivo system to perform such studies and present a protocol to measure in vivo oxidative stress. Taking advantage of fluorescent ROS probes and zebrafish transgenic fluorescent lines, we develop two different methods to measure oxidative stress in vivo: i) a “whole embryo ROS-detection method” for qualitative measurement of oxidative stress and ii) a “single-cell ROS detection method” for quantitative measurements of oxidative stress. Herein, we demonstrate the efficacy of these procedures by increasing oxidative stress in tissues by oxidant agents and physiological or genetic methods. This protocol is amenable for forward genetic screens and it will help address cause-effect relationships of ROS in animal models of oxidative stress-related pathologies such as neurological disorders and cancer.     

Role of oxygen and the OxyR protein in the response to iron limitation in Rhodobacter sphaeroides

Background

High intracellular levels of unbound iron can contribute to the production of reactive oxygen species (ROS) via the Fenton reaction, while depletion of iron limits the availability of iron-containing proteins, some of which have important functions in defence against oxidative stress. Vice versa increased ROS levels lead to the damage of proteins with iron sulphur centres. Thus, organisms have to coordinate and balance their responses to oxidative stress and iron availability. Our knowledge of the molecular mechanisms underlying the co-regulation of these responses remains limited. To discriminate between a direct cellular response to iron limitation and indirect responses, which are the consequence of increased levels of ROS, we compared the response of the α-proteobacterium Rhodobacter sphaeroides to iron limitation in the presence or absence of oxygen.

Results

One third of all genes with altered expression under iron limitation showed a response that was independent of oxygen availability. The other iron-regulated genes showed different responses in oxic or anoxic conditions and were grouped into six clusters based on the different expression profiles. For two of these clusters, induction in response to iron limitation under oxic conditions was dependent on the OxyR regulatory protein. An OxyR mutant showed increased ROS production and impaired growth under iron limitation.

Conclusion

Some R. sphaeroides genes respond to iron limitation irrespective of oxygen availability. These genes therefore reflect a “core iron response” that is independent of potential ROS production under oxic, iron-limiting conditions. However, the regulation of most of the iron-responsive genes was biased by oxygen availability. Most strikingly, the OxyR-dependent activation of a subset of genes upon iron limitation under oxic conditions, including many genes with a role in iron metabolism, revealed that elevated ROS levels were an important trigger for this response. OxyR thus provides a regulatory link between the responses to oxidative stress and to iron limitation in R. sphaeroides.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-794) contains supplementary material, which is available to authorized users.     

Relationships between functional traits and inorganic nitrogen acquisition among eight contrasting European grass species

Backgrounds and Aims Leaf functional traits have been used as a basis to categoize plants across a range of resource-use specialization, from those that conserve available resources to those that exploit them. However, the extent to which the leaf functional traits used to define the resource-use strategies are related to root traits and are good indicators of the ability of the roots to take up nitrogen (N) are poorly known. This is an important question because interspecific differences in N uptake have been proposed as one mechanism by which species’ coexistence may be determined. This study therefore investigated the relationships between functional traits and N uptake ability for grass species across a range of conservative to exploitative resource-use strategies.Methods Root uptake of NH4+ and NO3–, and leaf and root functional traits were measured for eight grass species sampled at three grassland sites across Europe, in France, Austria and the UK. Species were grown in hydroponics to determine functional traits and kinetic uptake parameters (I_max and K_m) under standardized conditions.Key Results Species with high specific leaf area (SLA) and shoot N content, and low leaf and root dry matter content (LDMC and RDMC, respectively), which are traits associated with the exploitative syndrome, had higher uptake and affinity for both N forms. No trade-off was observed in uptake between the two forms of N, and all species expressed a higher preference for NH4+.Conclusions The results support the use of leaf traits, and especially SLA and LDMC, as indicators of the N uptake ability across a broad range of grass species. The difficulties associated with assessing root properties are also highlighted, as root traits were only weakly correlated with leaf traits, and only RDMC and, to a lesser extent, root N content were related to leaf traits.     

Over-expression of Trxo1 increases the viability of tobacco BY-2 cells under H2O2 treatment

Background and Aims Reactive oxygen species (ROS), especially hydrogen peroxide, play a critical role in the regulation of plant development and in the induction of plant defence responses during stress adaptation, as well as in plant cell death. The antioxidant system is responsible for controlling ROS levels in these processes but redox homeostasis is also a key factor in plant cell metabolism under normal and stress situations. Thioredoxins (Trxs) are ubiquitous small proteins found in different cell compartments, including mitochondria and nuclei (Trxo1), and are involved in the regulation of target proteins through reduction of disulphide bonds, although their role under oxidative stress has been less well studied. This study describes over-expression of a Trxo1 for the first time, using a cell-culture model subjected to an oxidative treatment provoked by H₂O₂.Methods Control and over-expressing PsTrxo1 tobacco (Nicotiana tabacum) BY-2 cells were treated with 35 mm H₂O₂ and the effects were analysed by studying the growth dynamics of the cultures together with oxidative stress parameters, as well as several components of the antioxidant systems involved in the metabolism of H₂O₂. Analysis of different hallmarks of programmed cell death was also carried out.Key Results Over-expression of PsTrxo1 caused significant differences in the response of TBY-2 cells to high concentrations of H₂O₂, namely higher and maintained viability in over-expressing cells, whilst the control line presented a severe decrease in viability and marked indications of oxidative stress, with generalized cell death after 3 d of treatment. In over-expressing cells, an increase in catalase activity, decreases in H₂O₂ and nitric oxide contents and maintenance of the glutathione redox state were observed.Conclusions A decreased content of endogenous H₂O₂ may be responsible in part for the delayed cell death found in over-expressing cells, in which changes in oxidative parameters and antioxidants were less extended after the oxidative treatment. It is concluded that PsTrxo1 transformation protects TBY-2 cells from exogenous H₂O₂, thus increasing their viability via a process in which not only antioxidants but also Trxo1 seem to be involved.     

Reproductive biology of the horned viper,Cerastes cerastes gasperettii in the central region of Saudi Arabia

The reproductive biology of the horned viper, Cerastes cerastes gasperettii, in Riyadh region of Saudi Arabia was investigated over a period of one year. Study of reproductive cycle of male and female C. c. gasperettii revealed that the breeding season is relatively short (April and May). Thereafter females laid eggs by mid of July and hatching probably had taken place by the end of September. No activity was observed during winter, this may indicate just a single clutch per year. Relative testis weight to body weight was drastically increased (X¯ = 0.88%) during the peak of reproductive activity (May) where maximal expansion of seminiferous tubules was also attained during April and May (X¯ = 209 μm and 191 μm, respectively). Likewise, the ovarian activity was the highest during May where ovarian parameters were greater in terms of relative ovarian weight to body weight and ova diameter being 0.46% and 2.29 mm, respectively. Fat body weight was increased drastically just before the peak of reproductive activity then started to decline during June. It could be concluded that the harsh desert conditions and similar environments certainly affect reproductive activity of Saudi Arabian reptiles including snakes.     

The Fate of Chromosomes and Alleles in an Allohexaploid Brassica Population

Production of allohexaploid Brassica (2n = AABBCC) is a promising goal for plant breeders due to the potential for hybrid heterosis and useful allelic contributions from all three of the Brassica genomes present in the cultivated diploid (2n = AA, 2n = BB, 2n = CC) and allotetraploid (2n = AABB, 2n = AACC, and 2n = BBCC) crop species (canola, cabbages, mustards). We used high-throughput SNP molecular marker assays, flow cytometry, and fluorescent in situ hybridization (FISH) to characterize a population of putative allohexaploids derived from self-pollination of a hybrid from the novel cross (B. napus × B. carinata) × B. juncea to investigate whether fertile, stable allohexaploid Brassica can be produced. Allelic segregation in the A and C genomes generally followed Mendelian expectations for an F₂ population, with minimal nonhomologous chromosome pairing. However, we detected no strong selection for complete 2n = AABBCC chromosome complements, with weak correlations between DNA content and fertility (r² = 0.11) and no correlation between missing chromosomes or chromosome segments and fertility. Investigation of next-generation progeny resulting from one highly fertile F₂ plant using FISH revealed general maintenance of high chromosome numbers but severe distortions in karyotype, as evidenced by recombinant chromosomes and putative loss/duplication of A- and C-genome chromosome pairs. Our results show promise for the development of meiotically stable allohexaploid lines, but highlight the necessity of selection for 2n = AABBCC karyotypes.     

Sublethal vancomycin-induced ROS mediating antibiotic resistance in Staphylococcus aureus

Staphylococcus aureus is the leading cause of many human infectious diseases. Besides infectious dangers, S. aureus is well-known for the quickly developed drug resistance. Although great efforts have been made, mechanisms underlying the antibiotic effects of S. aureus are still not well clarified. Recently, reports have shown that oxidative stress connects with bactericidal antibiotics [Dwyer et al. (2009) Curr. Opin. Microbiol. 12, 482–489]. Based on this point, we demonstrate that reactive oxygen species (ROS) induced by sublethal vancomycin may be partly responsible for the antibiotic resistance in heterogeneous vancomycin resistant S. aureus (hVRSA). Sublethal vancomycin treatment may induce protective ROS productions in hVRSA, whereas reduction in ROS level in hVRSA strains may increase their vancomycin susceptibility. Moreover, low dose of ROS in VSSA (vancomycin susceptible S. aureus) strains may promote their survival under vancomycin conditions. Our findings reveal that modest ROS generation may be protective for vancomycin resistance in hVRSA. These results recover novel insights into the relationship between oxidative stress and bacterial resistance, which has important applications for further use of antibiotics and development of therapeutics strategies for hVRSA.     

The role of oxidative stress in lung injury induced by cigarette smoke

Oxidative stress is a damaging process resulting from an imbalance between excessive generation of oxidant compounds and insufficient antioxidant defence mechanisms. Oxidative stress plays a crucial role in the initiation and progression of cigarette smoke-induced lung injury, deterioration in lung functions, and development of chronic obstructive pulmonary disease (COPD). In smokers and in patients with COPD, the increased oxidant burden derives from cigarette smoke per se, and from activated inflammatory cells releasing enhanced amounts of reactive oxygen and nitrogen species (ROS, RNS, respectively). Although mild oxidative stress resulting from cigarette smoking leads to the upregulation of the antioxidative enzymes synthesis in the lungs, high levels of ROS and RNS observed in patients with COPD overwhelm the antioxidant enzymes capacities, resulting in oxidant-mediated lung injury and cell death. In addition, depletion of antioxidative systems in the systemic circulation was consistently observed in such patients. The imbalance between the generation of ROS/RNS and antioxidant capacities — the state of “oxidative stress” — is one of the major pathophysiologic hallmarks in the development of COPD. Detrimental effects of oxidative stress include impairment of membrane functions, inactivation of membrane-bound receptors and enzymes, and increased tissue permeability. In addition, oxidative stress aggravates the inflammatory processes in the lungs, and contributes to the worsening of the protease-antiprotease imbalance. Several markers of oxidative stress, such as increases in lipid peroxidation products and reductions in glutathione peroxidase activity, have been shown to be related to the reductions in pulmonary functions. In the present article we review the current knowledge about the vicious cycle of cigarette smoking, oxidative stress, and inflammation in the pathogenesis of COPD.     

Identification of genome-wide single nucleotide polymorphisms in allopolyploid crop Brassica napus

Background

Single nucleotide polymorphisms (SNPs) are the most common type of genetic variation. Identification of large numbers of SNPs is helpful for genetic diversity analysis, map-based cloning, genome-wide association analyses and marker-assisted breeding. Recently, identifying genome-wide SNPs in allopolyploid Brassica napus (rapeseed, canola) by resequencing many accessions has become feasible, due to the availability of reference genomes of Brassica rapa (2n = AA) and Brassica oleracea (2n = CC), which are the progenitor species of B. napus (2n = AACC). Although many SNPs in B. napus have been released, the objective in the present study was to produce a larger, more informative set of SNPs for large-scale and efficient genotypic screening. Hence, short-read genome sequencing was conducted on ten elite B. napus accessions for SNP discovery. A subset of these SNPs was randomly selected for sequence validation and for genotyping efficiency testing using the Illumina GoldenGate assay.

Results

A total of 892,536 bi-allelic SNPs were discovered throughout the B. napus genome. A total of 36,458 putative amino acid variants were located in 13,552 protein-coding genes, which were predicted to have enriched binding and catalytic activity as a result. Using the GoldenGate genotyping platform, 94 of 96 SNPs sampled could effectively distinguish genotypes of 130 lines from two mapping populations, with an average call rate of 92%.

Conclusions

Despite the polyploid nature of B. napus, nearly 900,000 simple SNPs were identified by whole genome resequencing. These SNPs were predicted to be effective in high-throughput genotyping assays (51% polymorphic SNPs, 92% average call rate using the GoldenGate assay, leading to an estimated >450 000 useful SNPs). Hence, the development of a much larger genotyping array of informative SNPs is feasible. SNPs identified in this study to cause non-synonymous amino acid substitutions can also be utilized to directly identify causal genes in association studies.     

Attenuation of hydrogen peroxide-mediated oxidative stress by Brassica juncea annexin-3 counteracts thiol-specific antioxidant (TSA1) deficiency in Saccharomyces cerevisiae

Brassica juncea annexin-3 (BjAnn3) was functionally characterized for its ability to modulate H₂O₂-mediated oxidative stress in Saccharomyces cerevisiae. BjAnn3 showed a significant protective role in cellular-defense against oxidative stress and partially alleviated inhibition of mitochondrial respiration in presence of exogenously applied H₂O₂. Heterologous expression of BjAnn3 protected membranes from oxidative stress-mediated damage and positively regulated antioxidant gene expression for ROS detoxification. We conclude that, BjAnn3 partially counteracts the effects of thioredoxin peroxidase 1 (TSA1) deficiency and aids in cellular-protection across kingdoms. Despite partial compensation of TSA1 by BjAnn3 in cell-viability tests, the over-complementation in ROS-related features suggests the existence of both redundant (e.g. ROS detoxification) and distinct features (e.g. membrane protection versus proximity-based redox regulator) of both proteins.