scholarly journals UMP Kinase Regulates Chloroplast Development and Cold Response in Rice

2019 ◽  
Vol 20 (9) ◽  
pp. 2107 ◽  
Author(s):  
Qing Dong ◽  
Ying-Xin Zhang ◽  
Quan Zhou ◽  
Qun-En Liu ◽  
Dai-Bo Chen ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Chloroplast Development ◽  
Cold Treatment ◽  
Building Blocks ◽  
Pyrimidine Nucleotides ◽  
Kinase Gene ◽  
High Accumulation ◽  
Cold Response ◽  
Chlorophyll Contents ◽  
Ump Kinase

Pyrimidine nucleotides are important metabolites that are building blocks of nucleic acids, which participate in various aspects of plant development. Only a few genes involved in pyrimidine metabolism have been identified in rice and the majority of their functions remain unclear. In this study, we used a map-based cloning strategy to isolate a UMPK gene in rice, encoding the UMP kinase that phosphorylates UMP to form UDP, from a recessive mutant with pale-green leaves. In the mutant, UDP content always decreased, while UTP content fluctuated with the development of leaves. Mutation of UMPK reduced chlorophyll contents and decreased photosynthetic capacity. In the mutant, transcription of plastid-encoded RNA polymerase-dependent genes, including psaA, psbB, psbC and petB, was significantly reduced, whereas transcription of nuclear-encoded RNA polymerase-dependent genes, including rpoA, rpoB, rpoC1, and rpl23, was elevated. The expression of UMPK was significantly induced by various stresses, including cold, heat, and drought. Increased sensitivity to cold stress was observed in the mutant, based on the survival rate and malondialdehyde content. High accumulation of hydrogen peroxide was found in the mutant, which was enhanced by cold treatment. Our results indicate that the UMP kinase gene plays important roles in regulating chloroplast development and stress response in rice.

scholarly journals Design and Synthesis of Antiviral Iminoribitol C-Nucleosides

2021 ◽  
Author(s):  
◽  
Ye Li
Keyword(s):  
Antiviral Activity ◽  
Rna Polymerase ◽  
Nucleoside Analogue ◽  
Rna Viruses ◽  
Active Form ◽  
Building Blocks ◽  
The Body ◽  
Nucleoside Analogues ◽  
Federal Drug Administration ◽  
Pharmacologically Active

<p>Infections caused by RNA viruses, such as Ebola and Zika, continue to exist worldwide as significant public health problems. In response to the urgent need for safer and more efficacious treatment options to treat infections caused by RNA viruses, the pharmaceutical and biotechnology industries have devoted significant efforts over the last two decades to discovering and developing new antiviral agents. One such antiviral, Sofosbuvir®, was approved by the US Federal Drug Administration (FDA) in 2014 and has revolutionized the treatment of Hepatitis-C. Sofosbuvir® was the second largest selling drug in the world in 2016 and in just twenty-one months Gilead reported sales worth $26.6 billion USD.The strategy of using nucleoside analogues to inhibit viral RNA dependent RNA polymerase(RdRp)has been pursued since the 1970s, and exemplified bythe discovery and development of ribavirin. The natural substrates of RNA polymerases are nucleoside triphosphates and often the efficacy of nucleoside analogues as antivirals are dependent on their ability to be converted by the host or virus to mono-, di-, and ultimately tri-phosphate analogues which block the active site of RNA polymerase as an analogue of the substrate causing chain termination. Recently Biocryst Pharmaceuticals (Biocryst) described the anti-viral properties of Immucillin-A (Galidesivir), an iminoribitol based nucleoside analogue, which was found to have broad spectrum antiviral activity especially against RNA viruses including Ebola. Researchers at the Ferrier Research Institute (Ferrier) have synthesizedan analogue of Immucillin-A, 8-aza-Immucillin-A (AIA) which shows comparable activityto Immucillin-A, in anti-viral screens against Ebola, and this antiviral activity forms part of a US patent application. The Ferrier is keen to further exemplify this compound class through the synthesis of analogues of both Immucillin-A and AIA as well as improve the overall synthesis of the lead compound AIA.Included as part of this study is the synthesis of pro-drugs of these iminoribitol based nucleoside analogues. Prodrugs are metabolized inside the body and are often converted to the corresponding pharmacologically active form. In general, prodrug strategies have improved the bioavailability and efficacy of many drugs. In particular, prodrugs strategies involving nucleoside analogue antivirals, which target RNA polymerase, have been particularly effective as they ensure conversion to the monophosphate in vivo. Conversion to the 5’-monophosphate form of a nucleoside analogue is the rate limiting step to the inhibition of the RNA polymerase –prior to its conversion to the triphosphateanalogue. The prodrug is effectively a protected monophosphate, and is then readily converted to monophosphate by the host and then onto the di-and tri-phosphate by kinases in both the host and virus. ProTide prodrugs, such as Sofosbuvir® provide a verified strategy for improving anti-viral activity and hence our desire to synthesize pro-drugs of all our iminoribitol based nucleoside analogues. This research thesis also involved repeating the known synthesis of the Immucillins, in particular, Immucillin-H (Forodesine), which requires in excess of 20 linear synthetic steps to make. The linear synthetic route to Immucillin-H was used instead of the more convenient convergent method developed by the Ferrier as several key synthetic intermediates in this progress were utilized in the attempted synthesis of some of the planned nucleoside analogues of AIA. As part of this work the candidate learned aspects of scaling up chemical reactions andthe critical analysis of both reaction hazards and reagent compatibilities at scale. Where possible and given the number of synthetic steps involved the candidate was also interested in improving the yields of the building blocks involved in the synthesis of the Immucillins with limited success.</p>

The Wheat Aquaporin Gene TaAQP7 Confers Tolerance to Cold Stress in Transgenic Tobacco

2014 ◽  
Vol 69 (3-4) ◽  
pp. 142-148 ◽  
Author(s):  
Chao Huang ◽  
Shiyi Zhou ◽  
Wei Hu ◽  
Xiaomin Deng ◽  
Shuya Wei ◽  
...  
Keyword(s):  
Cold Stress ◽  
Stress Tolerance ◽  
Transgenic Tobacco ◽  
Stress Responses ◽  
Cold Treatment ◽  
Membrane Damage ◽  
Pcr Analysis ◽  
Ion Leakage ◽  
Chlorophyll Contents ◽  
Aquaporin Gene

Aquaporin proteins (AQPs) have been shown to be involved in abiotic stress responses. However, the precise role of AQPs, especially in response to cold stress, is not understood in wheat (Triticum aestivum). In the present study, quantitative real time polymerase chain reaction (qRT-PCR) analysis revealed that TaAQP7 expression increased in leaves, but decreased in roots after cold treatment. Expression of TaAQP7 in tobacco plants resulted in increased root elongation and better growth compared with wild-type (WT) plants under cold stress. Moreover, after cold treatment, the transgenic tobacco lines exhibited higher chlorophyll contents, lower levels of malondialdehyde (MDA), and less ion leakage (IL) than WT plants. Thus, expression of TaAQP7 enhanced cold stress tolerance in transgenic tobacco. Taken together, our results suggest that TaAQP7 confers cold stress tolerance by relieving membrane damage in the transgenic plants.

scholarly journals Nitrogen Supply and Leaf Age Affect the Expression of TaGS1 or TaGS2 Driven by a Constitutive Promoter in Transgenic Tobacco

Genes ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 406 ◽  
Author(s):  
Yihao Wei ◽  
Aibo Shi ◽  
Xiting Jia ◽  
Zhiyong Zhang ◽  
Xinming Ma ◽  
...  
Keyword(s):  
Amino Acid ◽  
Nitrogen Metabolism ◽  
Soluble Protein ◽  
Leaf Age ◽  
Sufficient Conditions ◽  
Transcript Level ◽  
Nitrogen Supply ◽  
High Accumulation ◽  
Transcript Levels ◽  
Chlorophyll Contents

Glutamine synthetase (GS) plays a key role in nitrogen metabolism. Here, two types of tobacco transformants, overexpressing Triticum aestivum GS1 (TaGS1) or GS2 (TaGS2), were analysed. Four independent transformed lines, GS1-TR1, GS1-TR2, GS2-TR1 and GS2-TR2, were used for the nitrogen treatment. Under nitrogen-sufficient conditions, the leaves of GS2-TR showed high accumulation of the TaGS2 transcript, while those of GS1-TR showed a low TaGS1 transcript levels. However, compared with nitrogen-sufficient conditions, the TaGS1 transcript level increased in the leaves under nitrogen starvation, but the TaGS2 transcript level decreased. In addition, the TaGS1 and TaGS2 transcript levels were highest in the middle leaves under nitrogen-sufficient and starvation conditions. These results show that nitrogen supply and leaf age regulate TaGS expression, even when they are driven by a super-promoter. Additionally, in regard to nitrogen metabolism level, the lower leaves of the GS1-TR exhibited lower NH4+ and higher amino acid contents, while the upper leaves exhibited higher amino acid, soluble protein and chlorophyll contents. The leaves of the GS2-TR exhibited lower NH4+ but higher amino acid, soluble protein and chlorophyll contents. Given the role that GS isoforms play in nitrogen metabolism, these data suggest that TaGS1 overexpression may improve nitrogen transport, and that TaGS2 overexpression may improve nitrogen assimilation under nitrogen stress.

scholarly journals Identification of Genes Differentially Expressed in Response to Cold in Pisum sativum Using RNA Sequencing Analyses

Plants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 288 ◽  
Author(s):  
Nasser Bahrman ◽  
Emilie Hascoët ◽  
Odile Jaminon ◽  
Frédéric Dépta ◽  
Jean-François Hû ◽  
...  
Keyword(s):  
Low Temperature ◽  
Pisum Sativum ◽  
Rna Sequencing ◽  
Differentially Expressed Genes ◽  
Freezing Tolerance ◽  
Cold Treatment ◽  
Temperature Treatment ◽  
Differentially Expressed ◽  
Cold Response ◽  
Chilling Response

Low temperature stress affects growth and development in pea (Pisum sativum L.) and decreases yield. In this study, RNA sequencing time series analyses performed on lines, Champagne frost-tolerant and Térèse frost-sensitive, during a low temperature treatment versus a control condition, led us to identify 4981 differentially expressed genes. Thanks to our experimental design and statistical analyses, we were able to classify these genes into three sets. The first one was composed of 2487 genes that could be related to the constitutive differences between the two lines and were not regulated during cold treatment. The second gathered 1403 genes that could be related to the chilling response. The third set contained 1091 genes, including genes that could be related to freezing tolerance. The identification of differentially expressed genes related to cold, oxidative stress, and dehydration responses, including some transcription factors and kinases, confirmed the soundness of our analyses. In addition, we identified about one hundred genes, whose expression has not yet been linked to cold stress. Overall, our findings showed that both lines have different characteristics for their cold response (chilling response and/or freezing tolerance), as more than 90% of differentially expressed genes were specific to each of them.

WSL3, a component of the plastid-encoded plastid RNA polymerase, is essential for early chloroplast development in rice

2016 ◽  
Vol 92 (4-5) ◽  
pp. 581-595 ◽  
Author(s):  
Liwei Wang ◽  
Chunming Wang ◽  
Yihua Wang ◽  
Mei Niu ◽  
Yulong Ren ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Chloroplast Development ◽  
Plastid Rna Polymerase

scholarly journals Identification of Essential Subunits in the Plastid-Encoded RNA Polymerase Complex Reveals Building Blocks for Proper Plastid Development

2011 ◽  
Vol 157 (3) ◽  
pp. 1043-1055 ◽  
Author(s):  
Sebastian Steiner ◽  
Yvonne Schröter ◽  
Jeannette Pfalz ◽  
Thomas Pfannschmidt
Keyword(s):  
Rna Polymerase ◽  
Building Blocks ◽  
Plastid Development ◽  
Polymerase Complex

scholarly journals Synthetic logic circuits using RNA aptamer against T7 RNA polymerase

2014 ◽  
Author(s):  
Jongmin Kim ◽  
Juan F Quijano ◽  
Enoch Yeung ◽  
Richard M Murray
Keyword(s):  
Rna Polymerase ◽  
Expression System ◽  
Building Blocks ◽  
Logic Circuits ◽  
T7 Rna Polymerase ◽  
Free Expression ◽  
Rna Aptamer ◽  
Cell Free Expression System

Recent advances in nucleic acids engineering introduced several RNA-based regulatory components for synthetic gene circuits, expanding the toolsets to engineer organisms. In this work, we designed genetic circuits implementing an RNA aptamer previously described to have the capability of binding to the T7 RNA polymerase and inhibiting its activity in vitro. Using in vitro transcription assays, we first demonstrated the utility of the RNA aptamer in combination with programmable synthetic transcription networks. As a step to quickly assess the feasibility of aptamer functions in vivo, a cell-free expression system was used as a breadboard to emulate the in vivo conditions of E. coli. We tested the aptamer and its three sequence variants in the cell-free expression system, verifying the aptamer functionality in the cell-free testbed. In vivo expression of aptamer and its variants demonstrated control over GFP expression driven by T7 RNA polymerase with different response curves, indicating its ability to serve as building blocks for both logic circuits and transcriptional cascades. This work elucidates the potential of RNA-based regulators for cell programming with improved controllability leveraging the fast production and degradation time scales of RNA molecules.

scholarly journals Light Regulates the Cytokinin-Dependent Cold Stress Responses in Arabidopsis

2021 ◽  
Vol 11 ◽  
Author(s):  
Sylva Prerostova ◽  
Martin Černý ◽  
Petre I. Dobrev ◽  
Vaclav Motyka ◽  
Lucia Hluskova ◽  
...  
Keyword(s):  
Light Intensity ◽  
Cold Stress ◽  
Stress Tolerance ◽  
Stress Responses ◽  
Cold Treatment ◽  
Cytokinin Oxidase ◽  
Low Light ◽  
Cold Response ◽  
The Impact ◽  
Effect Of Light

To elucidate the effect of light intensity on the cold response (5°C; 7 days) in Arabidopsis thaliana, we compared the following parameters under standard light (150 μmol m–2 s–1), low light (20 μmol m–2 s–1), and dark conditions: membrane damage, photosynthetic parameters, cytokinin oxidase/dehydrogenase (CKX) activity, phytohormone levels, and transcription of selected stress- and hormone-related genes and proteome. The impact of cytokinins (CKs), hormones directly interacting with the light signaling pathway, on cold responses was evaluated using transformants overexpressing CK biosynthetic gene isopentenyl transferase (DEX:IPT) or CK degradation gene HvCKX2 (DEX:CKX) under a dexamethasone-inducible promoter. In wild-type plants, cold treatment under light conditions caused down-regulation of CKs (in shoots) and auxin, while abscisic acid (ABA), jasmonates, and salicylic acid (SA) were up-regulated, especially under low light. Cold treatment in the dark strongly suppressed all phytohormones, except ABA. DEX:IPT plants showed enhanced stress tolerance associated with elevated CK and SA levels in shoots and auxin in apices. Contrarily, DEX:CKX plants had weaker stress tolerance accompanied by lowered levels of CKs and auxins. Nevertheless, cold substantially diminished the impact from the inserted genes. Cold stress in dark minimized differences among the genotypes. Cold treatments in light strongly up-regulated stress marker genes RD29A, especially in roots, and CBF1-3 in shoots. Under control conditions, their levels were higher in DEX:CKX plants, but after 7-day stress, DEX:IPT plants exhibited the highest transcription. Transcription of genes related to CK metabolism and signaling showed a tendency to re-establish, at least partially, CK homeostasis in both transformants. Up-regulation of strigolactone-related genes in apices and leaves indicated their role in suppressing shoot growth. The analysis of leaf proteome revealed over 20,000 peptides, representing 3,800 proteins and 2,212 protein families (data available via ProteomeXchange, identifier PXD020480). Cold stress induced proteins involved in ABA and jasmonate metabolism, antioxidant enzymes, and enzymes of flavonoid and glucosinolate biosynthesis. DEX:IPT plants up-regulated phospholipase D and MAP-kinase 4. Cold stress response at the proteome level was similar in all genotypes under optimal light intensity, differing significantly under low light. The data characterized the decisive effect of light–CK cross-talk in the regulation of cold stress responses.

MdUGT88F1-mediated phloridzin biosynthesis coordinates carbon and nitrogen accumulation in apple

2021 ◽  
Author(s):  
Kun Zhou ◽  
Lingyu Hu ◽  
Hong Yue ◽  
Zhijun Zhang ◽  
Jingyun Zhang ◽  
...  
Keyword(s):  
Carbon Fixation ◽  
Chloroplast Development ◽  
Tricarboxylic Acid Cycle ◽  
Ammonium Assimilation ◽  
Light Sensitivity ◽  
Sugar Accumulation ◽  
Nitrogen Accumulation ◽  
High Accumulation ◽  
Carbon And Nitrogen

Abstract The high accumulation of phloridzin makes apple (Malus domestica) unique in the plant kingdom, which suggests a vital role of its biosynthesis in the physiological processes of apple. In our previous study, silencing MdUGT88F1 (a key UDP-glucose: phloretin 2'-O-glucosyltransferase gene) revealed the importance of phloridzin biosynthesis in apple development and Valsa canker resistance. Here, results from MdUGT88F1-silencing lines showed that phloridzin biosynthesis was indispensable for normal chloroplast development and photosynthetic carbon fixation by maintaining MdGLK1/2 expression. Interestingly, the increased phloridzin biosynthesis didn’t affect plant (or chloroplast) development but reduced nitrogen accumulation, leading to chlorophyll deficiency, light sensitivity, and sugar accumulation in MdUGT88F1-overexpressing apple lines during their growth and development. Further analysis revealed that MdUGT88F1-mediated phloridzin biosynthesis negatively regulated cytosolic glutamine synthetase1-asparagine synthetase-asparaginase (GS1-AS-ASPG) pathway of ammonium assimilation and limited chlorophyll synthesis in the shoots of apple. The interference of phloridzin biosynthesis in the GS1-AS-ASPG pathway was also assumed to be associated with its limitation of the carbon skeletons of ammonium assimilation through metabolic competition with the tricarboxylic acid cycle. Taken together, our findings shed light on the role of MdUGT88F1-mediated phloridzin biosynthesis in the coordination between carbon and nitrogen accumulation in apple trees.

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