scholarly journals AtFAHD1a: A New Player Influencing Seed Longevity and Dormancy in Arabidopsis?

2021 ◽  
Vol 22 (6) ◽  
pp. 2997
Author(s):  
Davide Gerna ◽  
Erwann Arc ◽  
Max Holzknecht ◽  
Thomas Roach ◽  
Pidder Jansen-Dürr ◽  
...  
Keyword(s):  
Redox State ◽  
Redox Regulation ◽  
Seed Quality ◽  
Seed Longevity ◽  
Wild Type ◽  
Sequence Alignments ◽  
Redox Poise ◽  
Threonic Acid ◽  
Fumarylacetoacetate Hydrolase ◽  
Seed Quality Traits

Fumarylacetoacetate hydrolase (FAH) proteins form a superfamily found in Archaea, Bacteria, and Eukaryota. However, few fumarylacetoacetate hydrolase domain (FAHD)-containing proteins have been studied in Metazoa and their role in plants remains elusive. Sequence alignments revealed high homology between two Arabidopsis thaliana FAHD-containing proteins and human FAHD1 (hFAHD1) implicated in mitochondrial dysfunction-associated senescence. Transcripts of the closest hFAHD1 orthologue in Arabidopsis (AtFAHD1a) peak during seed maturation drying, which influences seed longevity and dormancy. Here, a homology study was conducted to assess if AtFAHD1a contributes to seed longevity and vigour. We found that an A. thaliana T-DNA insertional line (Atfahd1a-1) had extended seed longevity and shallower thermo-dormancy. Compared to the wild type, metabolite profiling of dry Atfahd1a-1 seeds showed that the concentrations of several amino acids, some reducing monosaccharides, and δ-tocopherol dropped, whereas the concentrations of dehydroascorbate, its catabolic intermediate threonic acid, and ascorbate accumulated. Furthermore, the redox state of the glutathione disulphide/glutathione couple shifted towards a more reducing state in dry mature Atfahd1a-1 seeds, suggesting that AtFAHD1a affects antioxidant redox poise during seed development. In summary, AtFAHD1a appears to be involved in seed redox regulation and to affect seed quality traits such as seed thermo-dormancy and longevity.

scholarly journals Redox Regulation of Monodehydroascorbate Reductase by Thioredoxin y in Plastids Revealed in the Context of Water Stress

Antioxidants ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 183 ◽  
Author(s):  
Hélène Vanacker ◽  
Marjorie Guichard ◽  
Anne-Sophie Bohrer ◽  
Emmanuelle Issakidis-Bourguet
Keyword(s):  
Stress Tolerance ◽  
Redox State ◽  
Redox Regulation ◽  
Plant Stress ◽  
Monodehydroascorbate Reductase ◽  
Environmental Constraints ◽  
Wild Type ◽  
Response Network ◽  
Antioxidant Metabolites ◽  
Plant Stress Tolerance

Thioredoxins (TRXs) are key players within the complex response network of plants to environmental constraints. Here, the physiological implication of the plastidial y-type TRXs in Arabidopsis drought tolerance was examined. We previously showed that TRXs y1 and y2 have antioxidant functions, and here, the corresponding single and double mutant plants were studied in the context of water deprivation. TRX y mutant plants showed reduced stress tolerance in comparison with wild-type (WT) plants that correlated with an increase in their global protein oxidation levels. Furthermore, at the level of the main antioxidant metabolites, while glutathione pool size and redox state were similarly affected by drought stress in WT and trxy1y2 plants, ascorbate (AsA) became more quickly and strongly oxidized in mutant leaves. Monodehydroascorbate (MDA) is the primary product of AsA oxidation and NAD(P)H-MDA reductase (MDHAR) ensures its reduction. We found that the extractable leaf NADPH-dependent MDHAR activity was strongly activated by TRX y2. Moreover, activity of recombinant plastid Arabidopsis MDHAR isoform (MDHAR6) was specifically increased by reduced TRX y, and not by other plastidial TRXs. Overall, these results reveal a new function for y-type TRXs and highlight their role as major antioxidants in plastids and their importance in plant stress tolerance.

scholarly journals Requirement of ArcA for Redox Regulation in Escherichia coli under Microaerobic but Not Anaerobic or Aerobic Conditions

2003 ◽  
Vol 185 (1) ◽  
pp. 204-209 ◽  
Author(s):  
Svetlana Alexeeva ◽  
Klaas J. Hellingwerf ◽  
M. Joost Teixeira de Mattos
Keyword(s):  
Escherichia Coli ◽  
Redox State ◽  
Redox Regulation ◽  
Flux Distribution ◽  
Pyruvate Dehydrogenase Complex ◽  
Oxygen Availability ◽  
Flux Analysis ◽  
Wild Type ◽  
E Coli ◽  
Intracellular Redox

ABSTRACT In Escherichia coli, the two-component regulatory ArcAB system functions as a major control system for the regulation of expression of genes encoding enzymes involved in both aerobic and anaerobic catabolic pathways. Previously, we have described the physiological response of wild-type E. coli to changes in oxygen availability through the complete range from anaerobiosis to full aerobiosis (S. Alexeeva, B. de Kort, G. Sawers, K. J. Hellingwerf, and M. J. Teixeira de Mattos, J. Bacteriol. 182:4934-4940, 2000, and S. Alexeeva, K. J. Hellingwerf, and M. J. Teixeira de Mattos, J. Bacteriol. 184:1402-1406, 2002). Here, we address the question of the contribution of the ArcAB-dependent transcriptional regulation to this response. Wild-type E. coli and a mutant lacking the ArcA regulator were grown in glucose-limited chemostat cultures at controlled levels of oxygen availability ranging from full aerobiosis to complete anaerobiosis. A flux analysis of the distribution of catabolic fluxes over parallel pathways was carried out, and the intracellular redox state (as reflected by the NADH/NAD ratio) was monitored for all steady states. Deletion of ArcA neither significantly altered the in vivo activity of the pyruvate dehydrogenase complex and pyruvate formate lyase nor significantly affected catabolism under fully aerobic and fully anaerobic conditions. In contrast, profound effects of the absence of ArcA were seen under conditions of oxygen-restricted growth: increased respiration, an altered electron flux distribution over the cytochrome o- and d-terminal oxidases, and a significant change in the intracellular redox state were observed. Thus, the ArcA regulator was found to exert major control on flux distribution, and it is concluded that the ArcAB system should be considered a microaerobic redox regulator.

Potential of the C Genome of Different Variants of Brassica oleracea for the Improvement of Agronomic and Seed Quality Traits of B. napus Canola

Crop Science ◽  
2019 ◽  
Vol 59 (6) ◽  
pp. 2608-2620 ◽  
Author(s):  
Azam Nikzad ◽  
Berisso Kebede ◽  
Jaime Pinzon ◽  
Jani Bhavikkumar ◽  
Rong-Cai Yang ◽  
...  
Keyword(s):  
Brassica Oleracea ◽  
Seed Quality ◽  
Quality Traits ◽  
C Genome ◽  
Seed Quality Traits

Seed Germination and Seedling Vigour Improvement by Halophytic Seed Treatment in Black gram (Vigna mungo L.)

2021 ◽  
Author(s):  
R. Vinothini ◽  
K. Raja ◽  
R. Jerlin ◽  
S. Maragatham
Keyword(s):  
Tamil Nadu ◽  
Leaf Extract ◽  
Seed Quality ◽  
Black Gram ◽  
Salt Glands ◽  
Seedling Vigour ◽  
Aerial Parts ◽  
Salt Bladders ◽  
Seed Quality Traits ◽  
Physiological Characters

Background: Chenopodium plant is halophytic in nature in which the plant absorbs salt from soil and secrets the salts in aerial parts particularly in leaves and also has lot of macro and micro nutrients. This salt secretion by salt glands helps to survive the plants in saline conditions. The morpho-physiological characters act as barrier against mechanical damages, insects, excessive light and loss of water. Therefore, an experiment was conducted to enhance the seed quality traits viz., germination, speed of germination and seedling vigour in black gram by treating with the salt glands of Chenopodium.Methods: The experiment was conducted in the Department of Seed Science and Technology, Tamil Nadu Agricultural University, Coimbatore during 2019 - 2020. The black gram variety VBN 8 seeds were treated with different concentrations of Chenopodium leaf extract and salt bladders. Then, the seeds were assessed for its quality traits.Result: The experimental results showed that seeds soaked in Chenopodium leaf extract along with salt bladders @ 1.0% or salt bladders alone @ 0.2% for 3 h at 1:0.3 (w/v) ratio have recorded highest germination (97% and 96%) and seedling vigour (2280 and 2102). Nevertheless, analytical results indicated that the Chenopodium leaf extract and its salt bladders contain more amount of minerals particularly phosphorous (0.50%, 0.15%), potassium (0.83%, 1.11%), nitrogen (2.52%, 2.21%), calcium (16.00 ppm, 22.40 ppm), magnesium (190.56 ppm, 193.40 ppm), sodium (4.14 mg 100 g-1, 6.57 mg 100 g-1), chloride (0.14 mol. L-1, 0.17 mol. L-1), respectively, which favored the enhancement of seed qualities in black gram.

scholarly journals The Lack of Mitochondrial Thioredoxin TRXo1 Affects In Vivo Alternative Oxidase Activity and Carbon Metabolism under Different Light Conditions

2019 ◽  
Vol 60 (11) ◽  
pp. 2369-2381 ◽  
Author(s):  
Igor Florez-Sarasa ◽  
Toshihiro Obata ◽  
N�stor Fern�ndez Del-Saz ◽  
Jean-Philippe Reichheld ◽  
Etienne H Meyer ◽  
...  
Keyword(s):  
Carbon Metabolism ◽  
Redox State ◽  
Redox Regulation ◽  
Alternative Oxidase ◽  
Tricarboxylic Acid Cycle ◽  
Reduced Form ◽  
Photosynthetic Parameters ◽  
Primary Metabolism ◽  
Redox Systems

Abstract The alternative oxidase (AOX) constitutes a nonphosphorylating pathway of electron transport in the mitochondrial respiratory chain that provides flexibility to energy and carbon primary metabolism. Its activity is regulated in vitro by the mitochondrial thioredoxin (TRX) system which reduces conserved cysteines residues of AOX. However, in vivo evidence for redox regulation of the AOX activity is still scarce. In the present study, the redox state, protein levels and in vivo activity of the AOX in parallel to photosynthetic parameters were determined in Arabidopsis knockout mutants lacking mitochondrial trxo1 under moderate (ML) and high light (HL) conditions, known to induce in vivo AOX activity. In addition, 13C- and 14C-labeling experiments together with metabolite profiling were performed to better understand the metabolic coordination between energy and carbon metabolism in the trxo1 mutants. Our results show that the in vivo AOX activity is higher in the trxo1 mutants at ML while the AOX redox state is apparently unaltered. These results suggest that mitochondrial thiol redox systems are responsible for maintaining AOX in its reduced form rather than regulating its activity in vivo. Moreover, the negative regulation of the tricarboxylic acid cycle by the TRX system is coordinated with the increased input of electrons into the AOX pathway. Under HL conditions, while AOX and photosynthesis displayed similar patterns in the mutants, photorespiration is restricted at the level of glycine decarboxylation most likely as a consequence of redox imbalance.

scholarly journals Redox regulation of DNA binding activity of DREF (DNA replication-related element binding factor) in Drosophila

2004 ◽  
Vol 378 (3) ◽  
pp. 833-838 ◽  
Author(s):  
Tae-Yeong CHOI ◽  
S. Young PARK ◽  
Ho-Sung KANG ◽  
Jae-Hun CHEONG ◽  
Han-Do KIM ◽  
...  
Keyword(s):  
Dna Replication ◽  
Dna Binding ◽  
Redox State ◽  
Redox Regulation ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
Cell Extracts ◽  
Binding Factor ◽  
Related Element ◽  
Intracellular Redox

DREF [DRE (DNA replication-related element) binding factor] is an 80 kDa polypeptide homodimer which plays an important role in regulating cell proliferation-related genes. Both DNA binding and dimer formation activities are associated with residues 16–115 of the N-terminal region. However, the mechanisms by which DREF dimerization and DNA binding are regulated remain unknown. Here, we report that the DNA binding activity of DREF is regulated by a redox mechanism, and that the cysteine residues are involved in this regulation. Electrophoretic mobility shift analysis using Drosophila Kc cell extracts or recombinant DREF proteins indicated that the DNA binding domain is sufficient for redox regulation. Site-directed mutagenesis and transient transfection assays showed that Cys59 and/or Cys62 are critical both for DNA binding and for redox regulation, whereas Cys91 is dispensable. In addition, experiments using Kc cells indicated that the DNA binding activity and function of DREF are affected by the intracellular redox state. These findings give insight into the exact nature of DREF function in the regulation of target genes by the intracellular redox state.

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