scholarly journals The Phosphofructokinase Isoform AtPFK5 Is a Novel Target of Plastidic Thioredoxin-f-Dependent Redox Regulation

Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 401
Author(s):  
Natalia Hess ◽  
Simon Richter ◽  
Michael Liebthal ◽  
Karl-Josef Dietz ◽  
Angelika Mustroph
Keyword(s):  
Plant Growth ◽  
Redox Regulation ◽  
Chemical Oxidation ◽  
Pentose Phosphate ◽  
Primary Metabolism ◽  
Target Sequence ◽  
Carbohydrate Degradation ◽  
And Performance ◽  
Novel Target ◽  
Thioredoxin F

The chloroplast primary metabolism is of central importance for plant growth and performance. Therefore, it is tightly regulated in order to adequately respond to multiple environmental conditions. A major fluctuation that plants experience each day is the change between day and night, i.e., the change between assimilation and dissimilation. Among other mechanisms, thioredoxin-mediated redox regulation is an important component of the regulation of plastid-localized metabolic enzymes. While assimilatory processes such as the Calvin–Benson cycle are activated under illumination, i.e., under reducing conditions, carbohydrate degradation is switched off during the day. Previous analyses have identified enzymes of the oxidative pentose phosphate pathway to be inactivated by reduction through thioredoxins. In this work, we present evidence that an enzyme of the plastidic glycolysis, the phosphofructokinase isoform AtPFK5, is also inactivated through reduction by thioredoxins, namely by thioredoxin-f. With the help of chemical oxidation, mutant analyses and further experiments, the highly conserved motif CXDXXC in AtPFK5 was identified as the target sequence for this regulatory mechanism. However, knocking out this isoform in plants had only very mild effects on plant growth and performance, indicating that the complex primary metabolism in plants can overcome a lack in AtPFK5 activity.

scholarly journals Comprehensive analyses of the cysteine thiol oxidation of PKM2 reveal the effects of multiple oxidation on cellular oxidative stress response

2021 ◽  
Author(s):  
Hayato Irokawa ◽  
Satoshi Numasaki ◽  
Shin Kato ◽  
Kenta Iwai ◽  
Atsushi Inose-Maruyama ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Pyruvate Kinase ◽  
Redox Regulation ◽  
Cysteine Residue ◽  
Pentose Phosphate ◽  
Signal Pathways ◽  
Heterologous Proteins ◽  
Cancer Cell Growth ◽  
Anti Cancer ◽  
Cellular Signal

Redox regulation of proteins via cysteine residue oxidation is involved in the control of various cellular signal pathways. Pyruvate kinase M2 (PKM2), a rate-limiting enzyme in glycolysis, is critical for the metabolic shift from glycolysis to the pentose phosphate pathway under oxidative stress in cancer cell growth. The PKM2 tetramer is required for optimal pyruvate kinase (PK) activity, whereas the inhibition of inter-subunit interaction of PKM2 induced by Cys358 oxidation has reduced PK activity. In the present study, we identified three oxidation-sensitive cysteine residues (Cys358, Cys423 and Cys424) responsible for four oxidation forms via the thiol oxidant diamide and/or hydrogen peroxide (H2O2). Possibly due to obstruction of the dimer-dimer interface, H2O2-induced sulfenylation (-SOH) and diamide-induced modification at Cys424 inhibited tetramer formation and PK activity. Cys423 is responsible for intermolecular disulphide bonds with heterologous proteins via diamide. Additionally, intramolecular polysulphide linkage (–Sn–, n≧3) between Cys358 and an unidentified PKM2 Cys could be induced by diamide. We observed that cells expressing the oxidation-resistant PKM2 (PKM2C358,424A) produced more intracellular reactive oxygen species (ROS) and exhibited greater sensitivity to ROS-generating reagents and ROS-inducible anti-cancer drugs compared to cells expressing wildtype PKM2. These results highlight the possibility that PKM2 inhibition via Cys358 and Cys424 oxidation contributes to eliminating excess ROS and oxidative stress.

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.

Thioredoxin-like2/2-Cys peroxiredoxin redox cascade acts as oxidative activator of glucose-6-phosphate dehydrogenase in chloroplasts

2019 ◽  
Vol 476 (12) ◽  
pp. 1781-1790 ◽  
Author(s):  
Keisuke Yoshida ◽  
Eriko Uchikoshi ◽  
Satoshi Hara ◽  
Toru Hisabori
Keyword(s):  
Redox Regulation ◽  
Pentose Phosphate ◽  
Activation Mechanism ◽  
Protein Activation ◽  
Fluctuating Light ◽  
State Determination ◽  
Chloroplast Metabolism ◽  
Oxidative Activation ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Novel Protein

Abstract Thiol-based redox regulation is crucial for adjusting chloroplast functions under fluctuating light environments. We recently discovered that the thioredoxin-like2 (TrxL2)/2-Cys peroxiredoxin (2CP) redox cascade supports oxidative thiol modulation by using hydrogen peroxide (H2O2) as an oxidizing force. This system plays a key role in switching chloroplast metabolism (e.g. Calvin–Benson cycle) during light to dark transitions; however, information on its function is still limited. In this study, we report a novel protein-activation mechanism based on the TrxL2/2CP redox cascade. Glucose-6-phosphate dehydrogenase (G6PDH) catalyzes the first step of the oxidative pentose phosphate pathway (OPPP). Biochemical studies, including redox state determination and measurement of enzyme activity, suggested that the TrxL2/2CP pathway is involved in the oxidative activation of G6PDH. It is thus likely that the TrxL2/2CP redox cascade shifts chloroplast metabolism to night mode by playing a dual role, namely, down-regulation of the Calvin–Benson cycle and up-regulation of OPPP. G6PDH was also directly oxidized and activated by H2O2, particularly when H2O2 concentration was elevated. Therefore, G6PDH is thought to be finely tuned by H2O2 levels in both direct and indirect manners.

scholarly journals Propagule Type and Planting Time Affect Subsequent Mayapple Growth

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 640-644 ◽  
Author(s):  
Kent E. Cushman ◽  
Muhammad Maqbool
Keyword(s):  
Plant Growth ◽  
Leaf Area ◽  
Cultural Practices ◽  
Dry Mass ◽  
Planting Dates ◽  
Specialty Crops ◽  
Planting Time ◽  
Commercial Harvest ◽  
Plant Emergence ◽  
And Performance

Leaves of american mayapple (Podophyllum peltatum L.) contain podophyllotoxin, a compound of interest to the pharmaceutical industry. Cultural practices for establishment of mayapple in field plantings for commercial harvest have not been investigated. A factorial arrangement of three planting dates (Fall 2000, Spring 2001, or Summer 2001) and three propagule types (Nt+N1, Nt, or Nx; as described by Maqbool et al., 2004) were used to investigate strategies for establishing mayapple plantings. Rhizome segments were harvested from the wild and transplanted into plant beds in full sun in northern Mississippi. Plant emergence was recorded during March and April of each year from 2001 to 2004. Leaves within each plot were harvested as soon as they began to yellow, from the third week of April to the first week of June each year. Propagule type and planting time interacted to affect subsequent plant growth when measured on an area basis (per square meter of growing area). In 2004, spring-planted Nt+N1 produced more shoots with greater total leaf area and dry mass than spring-planted Nx or Nt. In contrast, Nt+N1 transplanted during fall or summer was equal in performance to that of Nx or Nt. Performance of summer-planted Nt was poor, producing far less leaf area and dry mass than any of the other treatment combinations. On a per plant basis, fall-planted propagules produced greater leaf area and dry mass in 2004 than spring- or summer-planted propagules, and Nt+N1 produced greater leaf area than Nx or Nt. The effect of year was not analyzed in this study due to complications of the experimental design. In conclusion, overall plant growth and performance of spring-planted Nt+N1 can be recommended as excellent and that of fall-planted Nt as poor. All other treatment combinations can be recommended as good. These results will assist growers of specialty crops in establishing mayapple plantings under field conditions in full sun.

scholarly journals Elevated CO2 induces age-dependent restoration of growth and metabolism in gibberellin-deficient plants

2019 ◽  
Author(s):  
Karla Gasparini ◽  
Lucas C. Costa ◽  
Fred A. L. Brito ◽  
Thaline M. Pimenta ◽  
Flávio Barcellos Cardoso ◽  
...  
Keyword(s):  
Plant Growth ◽  
Growth Stages ◽  
Photosynthetic Parameters ◽  
Primary Metabolism ◽  
Tomato Plants ◽  
Primary Metabolites ◽  
Stunted Growth ◽  
Age Dependent ◽  
Different Growth Stages ◽  
Ga Content

AbstractMain conclusion The effect of elevated [CO2] on the growth of tomato plants with reduced GA content is influenced by developmental stage.The increase of carbon dioxide (CO2) in the atmosphere during the last decades has aroused interest in the function of this gas in the growth and development of plants. Despite the known association between elevated CO2 concentration ([CO2]) and plant growth, its effects in association with gibberellin (GA), plant hormone that regulates de major aspects of plant growth, are still poorly understood. Therefore, we evaluated the effect of elevated [CO2] on growth and primary metabolism in tomato plants with drastic reduction in GA content (gib-1) at two different growth stages (21 and 35 days after germination, dag). Disruption on growth, photosynthetic parameters and primary metabolism were restored when gib-1 plants were transferred to elevated [CO2] at 21 dag. Elevated [CO2] also stimulated growth and photosynthetic parameters in Wild type (WT) plants at 21 dag, however, minor changes were observed in the level of primary metabolites. At 35 dag, elevated [CO2] did not stimulate growth in WT plants and gib-1 mutants showed their characteristic stunted growth phenotype.

scholarly journals COMPARISON OF ALTERNATIVE IRRIGATION SYSTEMS FOR CONTAINER NURSERY STOCK PRODUCTION

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 602b-602
Author(s):  
James B. Calkins ◽  
Bert T. Swanson ◽  
Daniel G. Krueger ◽  
Karin R. Lundquist
Keyword(s):  
Plant Growth ◽  
Water Use ◽  
Sprinkler Irrigation ◽  
Trickle Irrigation ◽  
Irrigation Systems ◽  
Nursery Stock ◽  
Use Efficiency ◽  
Irrigation Treatments ◽  
And Performance ◽  
Production Areas

A study was designed to ascertain the efficacy, water use efficiency, runoff potential, and cost effectiveness of four container irrigation systems: overhead sprinkler irrigation, in-line trickle irrigation, capillary mat with leaky hose, and sub-irrigation. Results were species dependent. Plant growth was best under capillary mat and trickle irrigation treatments, however, differences in plant growth and performance between irrigation treatments were minimal. Differences in water use, however, were quite significant. Overhead irrigation was inefficient regarding water use while capillary mat and trickle systems used much lower volumes of water. Conservative irrigation systems which maintain acceptable plant growth using less water and reduce runoff from container production areas can clearly benefit growers by reducing production and environmental costs.

scholarly journals Physiological and transcriptome analysis reveal molecular mechanism in Salvia miltiorrhiza leaves of near-isogenic male fertile lines and male sterile lines

2019 ◽  
Author(s):  
Ruihong Wang ◽  
Hongbo Guo ◽  
Juane Dong
Keyword(s):  
Plant Growth ◽  
Crop Production ◽  
Molecular Mechanisms ◽  
Leaf Gas Exchange ◽  
Salvia Miltiorrhiza ◽  
Underlying Mechanism ◽  
Metabolic Process ◽  
Primary Metabolism ◽  
Male Sterile ◽  
Physiological Analysis

Abstract Background: Our previous study found that male sterility in Salvia miltiorrhiza could result in stunted growth, decrease biomass, inhibit primary metabolism, and promote secondary metabolism, but their molecular mechanisms have not yet been elucidated. In this article, we investigated the underlying mechanism of plant growth and metabolism by using physiological analysis and mRNA sequencing (RNA-Seq). Results: In this study, transcriptomic and physiological analyses were performed to identify the effect on plant growth and metabolic production in male sterile mutants. Through GO and KEGG analysis it was found that the pathways were mainly enriched in processes including organ development, primary metabolic process and secondary metabolic process. Physiological analyses showed that the chloroplast structure of male sterile mutants of Salvia miltiorrhiza was abnormally developed, which could result in decrease in leaf gas exchange (A, E and gs), chlorophyll fluorescence (Fv, Fm and Fv/Fm), and the chlorophyll content. Transcriptomic analyses indicated that disproportionating enzyme 1 (DPE1) catalyzed the degradation of starch, while sucrose synthase 3 (SUS3) and cytosolic invertase 2 (CINV2) catalyzed the degradation of sucrose in S. miltiorrhiza. The results suggested that phenylalanine ammonialyase (PAL) played an important role in the biosynthesis of rosmarinic acid and salvianolic acid B, and flavone synthase (FLS) was an important enzyme catalyzing steps of flavonoid biosynthesis. High expression level of these enzyme genes in male sterile mutants resulted in high content of secondary metabolites. Conclusions: Our results from the physiological and transcriptome analyses reveal underlying mechanism of plant growth and metabolism in male sterile mutants, and provide insight into the crop production of S. miltiorrhiza.

The impact of photorespiration on plant primary metabolism through metabolic and redox regulation

2020 ◽  
Vol 48 (6) ◽  
pp. 2495-2504
Author(s):  
Stefan Timm
Keyword(s):  
Metabolic Regulation ◽  
Redox Regulation ◽  
Carbon Assimilation ◽  
Yield Potential ◽  
Primary Metabolism ◽  
Metabolic Route ◽  
Oxygenase Activity ◽  
Regulatory Impact ◽  
Photosynthetic Carbon Assimilation ◽  
The Impact

Photorespiration is an inevitable trait of all oxygenic phototrophs, being the only known metabolic route that converts the inhibitory side-product of Rubisco's oxygenase activity 2-phosphoglycolate (2PG) back into the Calvin–Benson (CB) cycle's intermediate 3-phosphoglycerate (3PGA). Through this function of metabolite repair, photorespiration is able to protect photosynthetic carbon assimilation from the metabolite intoxication that would occur in the present-day oxygen-rich atmosphere. In recent years, much plant research has provided compelling evidence that photorespiration safeguards photosynthesis and engages in cross-talk with a number of subcellular processes. Moreover, the potential of manipulating photorespiration to increase the photosynthetic yield potential has been demonstrated in several plant species. Considering this multifaceted role, it is tempting to presume photorespiration itself is subject to a suite of regulation mechanisms to eventually exert a regulatory impact on other processes, and vice versa. The identification of potential pathway interactions and underlying regulatory aspects has been facilitated via analysis of the photorespiratory mutant phenotype, accompanied by the emergence of advanced omics’ techniques and biochemical approaches. In this mini-review, I focus on the identification of enzymatic steps which control the photorespiratory flux, as well as levels of transcriptional, posttranslational, and metabolic regulation. Most importantly, glycine decarboxylase (GDC) and 2PG are identified as being key photorespiratory determinants capable of controlling photorespiratory flux and communicating with other branches of plant primary metabolism.

Micronutrients Considerations for Warm-Season Grass Systems in Florida

EDIS ◽  
2017 ◽  
Vol 2017 (6) ◽  
Author(s):  
Jane C. Griffin ◽  
Joao Mauricio Buen Vendramini ◽  
Diane L. Rowland ◽  
Maria Lucia Silveira
Keyword(s):  
Plant Growth ◽  
Production Systems ◽  
Warm Season ◽  
Ground Cover ◽  
Essential Elements ◽  
Forage Production ◽  
Warm Season Grass ◽  
And Performance ◽  
Warm Season Grasses

Warm-season grasses are vital to livestock production systems and dominate ground cover in tropical and subtropical areas. Many popular warm-season grasses, such as bahiagrass and bermudagrass, have roots that penetrate deeper into the soil profile, which aids in both drought tolerance, nutrient uptake, and the minimization of soil erosion. In Florida, spodosols are the predominant soil order used for forage production and have limited fertility. Micronutrients are essential elements that are required in smaller quantities than macronutrients but are equally as important for proper plant growth and performance. An element can be considered essential for plant growth if a plant fails to complete its life cycle in the absence of the element, the elements action is specific and cannot be completely replaced by another element, it has a direct effect on the organism, or it is a constituent of a molecule that is known to be essential. The objective of this publication is to describe the role of micronutrients in warm-season grass production.

scholarly journals Thiol Redox Sensitivity of Two Key Enzymes of Heme Biosynthesis and Pentose Phosphate Pathways: Uroporphyrinogen Decarboxylase and Transketolase

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Brian McDonagh ◽  
José Rafael Pedrajas ◽  
C. Alicia Padilla ◽  
José Antonio Bárcena
Keyword(s):  
Redox Regulation ◽  
Tumour Progression ◽  
Pentose Phosphate ◽  
Heme Biosynthesis ◽  
Label Free ◽  
Uroporphyrinogen Decarboxylase ◽  
Cell Extracts ◽  
Thiol Redox

Uroporphyrinogen decarboxylase (Hem12p) and transketolase (Tkl1p) are key mediators of two critical processes within the cell, heme biosynthesis, and the nonoxidative part of the pentose phosphate pathway (PPP). The redox properties of both Hem12p and Tkl1p fromSaccharomyces cerevisiaewere investigated using proteomic techniques (SRM and label-free quantification) and biochemical assays in cell extracts andin vitrowith recombinant proteins. Thein vivoanalysis revealed an increase in oxidized Cys-peptides in the absence of Grx2p, and also after treatment with H2O2in the case of Tkl1p, without corresponding changes in total protein, demonstrating a true redox response. Out of three detectable Cys residues in Hem12p, only the conserved residue Cys52 could be modified by glutathione and efficiently deglutathionylated by Grx2p, suggesting a possible redox control mechanism for heme biosynthesis. On the other hand, Tkl1p activity was sensitive to thiol redox modification and although Cys622 could be glutathionylated to a limited extent, it was not a natural substrate of Grx2p. The human orthologues of both enzymes have been involved in certain cancers and possess Cys residues equivalent to those identified as redox sensitive in yeast. The possible implication for redox regulation in the context of tumour progression is put forward.

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