scholarly journals Tolerance to oxidative stress is associated with both oxidative stress response and inherent growth in a fungal wheat pathogen

Genetics ◽  
2020 ◽  
Vol 217 (2) ◽  
Author(s):  
Ziming Zhong ◽  
Bruce A McDonald ◽  
Javier Palma-Guerrero
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Stress Tolerance ◽  
Stress Responses ◽  
Plant Pathogens ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Zymoseptoria Tritici ◽  
Oxidative Stress Tolerance ◽  
Animal Pathogens

Abstract Reactive oxygen species are toxic byproducts of aerobic respiration that are also important in mediating a diversity of cellular functions. Reactive oxygen species form an important component of plant defenses to inhibit microbial pathogens during pathogen–plant interactions. Tolerance to oxidative stress is likely to make a significant contribution to the viability and pathogenicity of plant pathogens, but the complex network of oxidative stress responses hinders identification of the genes contributing to this trait. Here, we employed a forward genetic approach to investigate the genetic architecture of oxidative stress tolerance in the fungal wheat pathogen Zymoseptoria tritici. We used quantitative trait locus (QTL) mapping of growth and melanization under axenic conditions in two cross-populations to identify genomic regions associated with tolerance to oxidative stress. We found that QTLs associated with growth under oxidative stress as well as inherent growth can affect oxidative stress tolerance, and we identified two uncharacterized genes in a major QTL associated with this trait. Our data suggest that melanization does not affect tolerance to oxidative stress, which differs from what was found for animal pathogens. This study provides a whole-genome perspective on the genetic basis of oxidative stress tolerance in a plant pathogen.

scholarly journals Genetic architecture of oxidative stress tolerance in the fungal wheat pathogen Zymoseptoria tritici

2020 ◽  
Author(s):  
Ziming Zhong ◽  
Bruce A. McDonald ◽  
Javier Palma-Guerrero
Keyword(s):  
Oxidative Stress ◽  
Stress Tolerance ◽  
Stress Responses ◽  
Genetic Architecture ◽  
Plant Pathogens ◽  
Fungal Growth ◽  
Microbial Pathogens ◽  
Zymoseptoria Tritici ◽  
Oxidative Stress Tolerance ◽  
Trade Off

ABSTRACTReactive oxygen species are toxic byproducts of aerobic respiration produced during cell growth. They also are an important component of plant defenses to inhibit microbial pathogens. Tolerance to oxidative stress contributes to viability and pathogenicity of plant pathogens. However, the complex molecular network of oxidative stress responses hinders identification of the genes contributing to variation in this trait. Variation in genes affecting responses to oxidative stress is likely to affect the evolutionary potential of pathogen tolerance to host defences. Here, we employed a forward genetic approach to investigate the genetic architecture of oxidative stress tolerance in the fungal wheat pathogen Zymoseptoria tritici. By performing quantitative trait locus (QTL) mapping in two crosses, we identified several genomic regions associated with tolerance to oxidative stress, including a QTL having a large effect on growth under oxidative stress. We found evidence for a significant trade-off between growth under non-stressful conditions and growth inhibition under oxidative stress. We identified a large QTL associated with this trade-off and with growth under non-stressful conditions, suggesting that differences in fungal growth could result in different sensitivities to oxidative stress. Our results suggest that genes related to fungal growth could also contribute to variation in oxidative stress tolerance among fungal strains.

scholarly journals Distinct Signaling Pathways Respond to Arsenite and Reactive Oxygen Species in Schizosaccharomyces pombe

2005 ◽  
Vol 4 (8) ◽  
pp. 1396-1402 ◽  
Author(s):  
Miguel A. Rodríguez-Gabriel ◽  
Paul Russell
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Schizosaccharomyces Pombe ◽  
Stress Responses ◽  
Biological Effects ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Increased Risk ◽  
Risk Of Cancer

ABSTRACT Exposure to certain metal and metalloid species, such as arsenic, cadmium, chromium, and nickel, has been associated with an increased risk of cancer in humans. The biological effects of these metals are thought to result from induction of reactive oxygen species (ROS) and inhibition of DNA repair enzymes, although alterations in signal transduction pathways may also be involved in tumor development. To better understand metal toxicity and its connection to ROS, we have compared the effects of arsenite and hydrogen peroxide in wild-type and mutant strains of the fission yeast Schizosaccharomyces pombe. An atf1Δ pap1Δ strain, which is defective in two transcription factors that control stress responses, is extremely sensitive to hydrogen peroxide but not to arsenite. A strain that lacks the transcription factor Zip1 has the opposite relationship. Spc1 (Sty1) mitogen-activated protein kinase (MAPK), a homologue of mammalian p38 MAPK, and the upstream MAPK kinase (MAPKK) Wis1 are essential for survival of both arsenite and hydrogen peroxide. Inactivation of two MAPKK kinases, Win1 and Wis4, almost completely eliminates Spc1 activation by arsenite, yet these cells survive arsenite treatment. The two-component phosphorelay protein Mcs4, which acts upstream of Win1 and Wis4 and is required for Spc1 activation in response to oxidative stress, is not required for Spc1 activation in response to arsenite. We conclude that the toxic effects of arsenic are not strongly connected to oxidative stress and that although Spc1 is activated by arsenic exposure, the basal activity of Spc1 is largely sufficient for the survival of arsenic.

scholarly journals Effects of Salicylic Acid on the Metabolism of Mitochondrial Reactive Oxygen Species in Plants

Biomolecules ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 341 ◽  
Author(s):  
Péter Poór
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Salicylic Acid ◽  
Stress Responses ◽  
Current Knowledge ◽  
Reactive Oxygen ◽  
Defense Responses ◽  
Full Detail ◽  
Oxygen Species ◽  
Cell Organelles

Different abiotic and biotic stresses lead to the production and accumulation of reactive oxygen species (ROS) in various cell organelles such as in mitochondria, resulting in oxidative stress, inducing defense responses or programmed cell death (PCD) in plants. In response to oxidative stress, cells activate various cytoprotective responses, enhancing the antioxidant system, increasing the activity of alternative oxidase and degrading the oxidized proteins. Oxidative stress responses are orchestrated by several phytohormones such as salicylic acid (SA). The biomolecule SA is a key regulator in mitochondria-mediated defense signaling and PCD, but the mode of its action is not known in full detail. In this review, the current knowledge on the multifaceted role of SA in mitochondrial ROS metabolism is summarized to gain a better understanding of SA-regulated processes at the subcellular level in plant defense responses.

Functional comparison of Deinococcus radiodurans Dps proteins suggests distinct in vivo roles

2012 ◽  
Vol 447 (3) ◽  
pp. 381-391 ◽  
Author(s):  
Brian J. Reon ◽  
Khoa H. Nguyen ◽  
Gargi Bhattacharyya ◽  
Anne Grove
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Signal Peptide ◽  
Stress Responses ◽  
Cellular Localization ◽  
Fluorescent Protein ◽  
Deinococcus Radiodurans ◽  
Reactive Oxygen ◽  
Oxygen Species

Deinococcus radiodurans exhibits extreme resistance to DNA damage and is one of only few bacteria that encode two Dps (DNA protection during starvation) proteins. Dps-1 was shown previously to bind DNA with high affinity and to localize to the D. radiodurans nucleoid. A unique feature of Dps-2 is its predicted signal peptide. In the present paper, we report that Dps-2 assembly into a dodecamer requires the C-terminal extension and, whereas Dps-2 binds DNA with low affinity, it protects against degradation by reactive oxygen species. Consistent with a role for Dps-2 in oxidative stress responses, the Dps-2 promoter is up-regulated by oxidative stress, whereas the Dps-1 promoter is not. Although DAPI (4′,6-diamidino-2-phenylindole) staining of Escherichia coli nucleoids shows that Dps-1 can compact genomic DNA, such nucleoid condensation is absent from cells expressing Dps-2. A fusion of EGFP (enhanced green fluorescent protein) to the Dps-2 signal peptide results in green fluorescence at the perimeter of D. radiodurans cells. The differential response of the Dps-1 and Dps-2 promoters to oxidative stress, the distinct cellular localization of the proteins and the differential ability of Dps-1 and Dps-2 to attenuate hydroxyl radical production suggest distinct functional roles; whereas Dps-1 may function in DNA metabolism, Dps-2 may protect against exogenously derived reactive oxygen species.

scholarly journals Overexpression of a Metallothionein 2A Gene from Date Palm Confers Abiotic Stress Tolerance to Yeast and Arabidopsis thaliana

2019 ◽  
Vol 20 (12) ◽  
pp. 2871 ◽  
Author(s):  
Himanshu V. Patankar ◽  
Ibtisam Al-Harrasi ◽  
Latifa Al Kharusi ◽  
Gerry Aplang Jana ◽  
Rashid Al-Yahyai ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Abiotic Stress ◽  
Transgenic Plants ◽  
Stress Tolerance ◽  
Date Palm ◽  
Oxygen Species ◽  
In Planta ◽  
Oxidative Stress Tolerance ◽  
And Oxidative Stress

Although the date palm tree is an extremophile with tolerance to drought and certain levels of salinity, the damage caused by extreme salt concentrations in the soil, has created a need to explore stress-responsive traits and decode their mechanisms. Metallothioneins (MTs) are low-molecular-weight cysteine-rich proteins that are known to play a role in decreasing oxidative damage during abiotic stress conditions. Our previous study identified date palm metallothionein 2A (PdMT2A) as a salt-responsive gene, which has been functionally characterized in yeast and Arabidopsis in this study. The recombinant PdMT2A protein produced in Escherichia coli showed high reactivity against the substrate 5′-dithiobis-2-nitrobenzoic acid (DTNB), implying that the protein has the property of scavenging reactive oxygen species (ROS). Heterologous overexpression of PdMT2A in yeast (Saccharomyces cerevisiae) conferred tolerance to drought, salinity and oxidative stresses. The PdMT2A gene was also overexpressed in Arabidopsis, to assess its stress protective function in planta. Compared to the wild-type control, the transgenic plants accumulated less Na+ and maintained a high K+/Na+ ratio, which could be attributed to the regulatory role of the transgene on transporters such as HKT, as demonstrated by qPCR assay. In addition, transgenic lines exhibited higher chlorophyll content, higher superoxide dismutase (SOD) activity and improved scavenging ability for reactive oxygen species (ROS), coupled with a better survival rate during salt stress conditions. Similarly, the transgenic plants also displayed better drought and oxidative stress tolerance. Collectively, both in vitro and in planta studies revealed a role for PdMT2A in salt, drought, and oxidative stress tolerance.

scholarly journals Arabidopsis thaliana Trihelix Transcription factor AST1 mediates abiotic stress tolerance by binding to a novel AGAG-box and some GT motifs

2017 ◽  
Author(s):  
Hongyun Xu ◽  
Lin He ◽  
Yong Guo ◽  
Xinxin Shi ◽  
Dandan Zang ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Abiotic Stress ◽  
Stress Tolerance ◽  
Stress Responses ◽  
Abiotic Stress Tolerance ◽  
Light Stress ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Qrt Pcr ◽  
Helix Loop Helix

AbstractTrihelix transcription factors are characterized by containing a conserved trihelix (helix-loop-helix-loop-helix) domain that bind to GT elements required for light response, play roles in light stress, and also in abiotic stress responses. However, only few of them have been functionally characterised. In the present study, we characterized the function of AST1 (Arabidopsis SIP1 clade Trihelix1) in response to abiotic stress. AST1 shows transcriptional activation activity, and its expression is induced by osmotic and salt stress. The genes regulated by AST1 were identified using qRT-PCR and transcriptome assays. A conserved sequence highly present in the promoters of genes regulated by AST1 was identified, which is bound by AST1, and termed AGAG-box with the sequence [A/G][G/A][A/T]GAGAG. Additionally, AST1 also binds to some GT motifs including GGTAATT, TACAGT, GGTAAAT and GGTAAA, but failed in binding to GTTAC and GGTTAA. Chromatin immunoprecipitation combined with qRT-PCR analysis suggested that AST1 binds to AGAG-box and/or some GT motifs to regulate the expression of stress tolerance genes, resulting in reduced reactive oxygen species, Na+ accumulation, stomatal apertures, lipid peroxidation, cell death and water loss rate, and increased proline content and reactive oxygen species scavenging capability. These physiological changes mediated by AST1 finally improve abiotic stress tolerance.

scholarly journals Differences in Antibiotic-Induced Oxidative Stress Responses between Laboratory and Clinical Isolates of Streptococcus pneumoniae

2015 ◽  
Vol 59 (9) ◽  
pp. 5420-5426 ◽  
Author(s):  
Bédis Dridi ◽  
Andréanne Lupien ◽  
Michel G. Bergeron ◽  
Philippe Leprohon ◽  
Marc Ouellette
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Streptococcus Pneumoniae ◽  
Stress Responses ◽  
Bacterial Species ◽  
Reactive Oxygen ◽  
Clinical Isolates ◽  
Complex Nature ◽  
Oxygen Species ◽  
Content Type

ABSTRACTOxidants were shown to contribute to the lethality of bactericidal antibiotics in different bacterial species, including the laboratory strainStreptococcus pneumoniaeR6. Resistance to penicillin amongS. pneumoniaeR6 mutants was further shown to protect against the induction of oxidants upon exposure to unrelated bactericidal compounds. In the work described here, we expanded on these results by studying the accumulation of reactive oxygen species in the context of antibiotic sensitivity and resistance by includingS. pneumoniaeclinical isolates. InS. pneumoniaeR6, penicillin, ciprofloxacin, and kanamycin but not the bacteriostatic linezolid, erythromycin, or tetracycline induced the accumulation of reactive oxygen species. For the three bactericidal compounds, resistance to a single molecule prevented the accumulation of oxidants upon exposure to unrelated bactericidal antibiotics, and this was accompanied by a reduced lethality. This phenomenon does not involve target site mutations but most likely implicates additional mutations occurring early during the selection of resistance to increase survival while more efficient resistance mechanisms are being selected or acquired. Bactericidal antibiotics also induced oxidants in sensitiveS. pneumoniaeclinical isolates. The importance of oxidants in the lethality of bactericidal antibiotics was less clear than forS. pneumoniaeR6, however, since ciprofloxacin induced oxidants even in ciprofloxacin-resistantS. pneumoniaeclinical isolates. Our results provide a clear example of the complex nature of the mode of action of antibiotics. The adaptive approach to oxidative stress ofS. pneumoniaeis peculiar, and a better understanding of the mechanism implicated in response to oxidative injury should also help clarify the role of oxidants induced by antibiotics.

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