A 5-Enolpyruvylshikimate 3-Phosphate Synthase Functions as a Transcriptional Repressor in <i>Populus</i>

Xie, Meng; Muchero, Wellington; Bryan, Anthony C.; Yee, Kelsey; Guo, Haobo; Zhang, Jin; Tschaplinski, Timothy J.; Singan, Vasanth; Lindquist, Erika; Payyavula, Raja S.; Barros-Ríos, Jaime; Dixon, Richard A.; Engle, Nancy L.; Sykes, Robert; Davis, Mark F.; Jawdy, Sara; Gunter, Lee E.; Thompson, Olivia A.; DiFazio, Stephen P.; Evans, Luke M.; Winkeler, Kim; Collins, Cassandra M.; Schmutz, Jeremy; Guo, Hong; Kalluri, Udaya C.; Rodríguez, Miguel; Feng, Kai; Chen, Jay; Tuskan, Gerald A.

doi:10.1105/tpc.18.00168

Cited by 68 publications

(83 citation statements)

References 81 publications

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“…Compared to the wild type, transgenic poplars overexpressing PtrEPSP-TF showed ectopic deposition of lignin, accumulation of phenylpropanoids, differential expression of SCW biosynthetic genes, and higher sugar release during enzymatic saccharification, but without notable yield change in field trials [62,63]. Notably, PtrEPSP-TF harbors an additional N-terminal HTH DNA-binding motif that partially targets this protein to the nucleus, where it acts as a transcriptional repressor of its direct target PtrhAT, a hAT transposase family gene.…”

Section: R2r3 Mybs the Gatekeepers Of Scw Formation And Lignificationmentioning

confidence: 95%

“…In addition to having repressive activity on lignin biosynthesis, a novel transcriptional regulatory mechanism for MYBs has been recently uncovered [62] that regulates the flow of carbon into the phenylpropanoid pathway and lignin biosynthesis through direct repression of PtrMYB021 (Figure 1). Association mapping identified significant correlations between lignin content and one of the two paralogs of 5-enolpyruvylshikimate 3-phosphate synthase gene (PtrEPSP-TF, Potri.002G146400).…”

Section: R2r3 Mybs the Gatekeepers Of Scw Formation And Lignificationmentioning

confidence: 99%

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A Molecular Blueprint of Lignin Repression

Behr¹,

Guerriero²,

Grima‐Pettenati³

et al. 2019

Trends in Plant Science

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Although lignin is essential to ensure the correct growth and development of land plants, it may be an obstacle to the production of lignocellulosics-based biofuels, and reduces the nutritional quality of crops used for human consumption or livestock feed. The need to tailor the lignocellulosic biomass for more efficient biofuel production or for improved plant digestibility has fostered considerable advances in our understanding of the lignin biosynthetic pathway and its regulation. Most of the described regulators are transcriptional activators of lignin biosynthesis, but considerably less attention has been devoted to the repressors of this pathway. We provide a comprehensive overview of the molecular factors that negatively impact on the lignification process at both the transcriptional and post-transcriptional levels. Challenging LigninLignin is a major cell wall component that fulfills fundamental functions in plant development as well as in defense against pests and pathogens. This heteropolymer impregnates the compound middle lamella and the secondary cell walls (SCWs) of cells genetically programmed to be lignified, such as xylem tracheary elements as well as xylem and phloem fibers. Lignin biosynthesis spans the phenylpropanoid and the monolignol pathways, from phenylalanine to p-coumaryl, coniferyl, and sinapyl alcohols. Monolignol homeostasis is regulated through a balance between the molecular factors that antagonistically regulate their biosynthesis. After monolignols are excreted into the apoplast, they are oxidized by the phenol-oxidoreductase laccases and/or by class III peroxidases, and are polymerized by radical coupling. A complex regulatory network involving phytohormones, transcription factors (TFs), and post-transcriptional events guide SCW deposition and lignification [1]. This network prevents lignin deposition in tissues undergoing active division or elongation such as apical meristems, vascular cambium, and immature xylem cells, as well as in non-lignified tissues such as stem pith and flax or hemp bast fibers that harbor gelatinous walls under normal developmental conditions. Similarly, this network negatively regulates lignification in xylem tissue formed in response to mechanical stresses such as, for instance, poplar tension wood that harbors hypolignified gelatinous walls.

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Section: R2r3 Mybs the Gatekeepers Of Scw Formation And Lignificationmentioning

confidence: 95%

Section: R2r3 Mybs the Gatekeepers Of Scw Formation And Lignificationmentioning

confidence: 99%

A Molecular Blueprint of Lignin Repression

Behr¹,

Guerriero²,

Grima‐Pettenati³

et al. 2019

Trends in Plant Science

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“…It has been claimed that the expected higher metabolic cost associated with EPSPS overexpression may be offset if the concomitant higher concentration of EPSPS, its downstream products (aromatic amino acids, secondary compounds, lignin, auxin) and transcriptional regulatory functions (Xie et al ., ) endows a selective advantage in a glyphosate‐free environment (Beres et al ., ; Fang et al ., ). In natural environments, it is possible that pressure from herbivory could select for glyphosate‐resistant plants overproducing alkaloids and tannins via EPSPS gene amplification/overexpression.…”

Section: Does Glyphosate Resistance By Epsps Gene Amplification and Omentioning

confidence: 99%

Do plants pay a fitness cost to be resistant to glyphosate?

Vila‐Aiub

Powles

2019

New Phytologist

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Summary We reviewed the literature to understand the effects of glyphosate resistance on plant fitness at the molecular, biochemical and physiological levels. A number of correlations between enzyme characteristics and glyphosate resistance imply the existence of a plant fitness cost associated with resistance‐conferring mutations in the glyphosate target enzyme, 5‐enolpyruvylshikimate‐3‐phosphate synthase (EPSPS). These biochemical changes result in a tradeoff between the glyphosate resistance of the EPSPS enzyme and its catalytic activity. Mutations that endow the highest resistance are more likely to decrease catalytic activity by reducing the affinity of EPSPS for its natural substrate, and/or slowing the velocity of the enzyme reaction, and are thus very likely to endow a substantial plant fitness cost. Prediction of fitness costs associated with EPSPS gene amplification and overexpression can be more problematic. The validity of cost prediction based on the theory of evolution of gene expression and resource allocation has been cast into doubt by contradictory experimental evidence. Further research providing insights into the role of the EPSPS cassette in weed adaptation, and estimations of the energy budget involved in EPSPS amplification and overexpression are required to understand and predict the biochemical and physiological bases of the fitness cost of glyphosate resistance.

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“…For example, a relatively short MD simulation was able to visualize the opening‐and‐closing dynamics associated with the regulatory functions of mercury‐dependent transcription regulator, MerR . In another example, MD simulation deciphered the transcriptional repression function of an EPSP synthase in Populus , and transplant of this gene into crops had been found to significantly increase the sugar (cellulose) contents . Computer simulations obey the Moose law; and the first MD trajectory reached 1 ms in 2010, indicating that MD simulations can be applied to physiologically relevant timescales.…”

Section: Introductionmentioning

confidence: 99%

Advancing Aptamers as Molecular Probes for Cancer Theranostic Applications—The Role of Molecular Dynamics Simulation

Jeevanandam

Tan

Danquah

et al. 2020

Biotechnology Journal

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Theranostics cover emerging technologies for cell biomarking for disease diagnosis and targeted introduction of drug ingredients to specific malignant sites. Theranostics development has become a significant biomedical research endeavor for effective diagnosis and treatment of diseases, especially cancer. An efficient biomarking and targeted delivery strategy for theranostic applications requires effective molecular coupling of binding ligands with high affinities to specific receptors on the cancer cell surface. Bioaffinity offers a unique mechanism to bind specific target and receptor molecules from a range of non‐targets. The binding efficacy depends on the specificity of the affinity ligand toward the target molecule even at low concentrations. Aptamers are fragments of genetic materials, peptides, or oligonucleotides which possess enhanced specificity in targeting desired cell surface receptor molecules. Aptamer–target binding results from several inter‐molecular interactions including hydrogen bond formation, aromatic stacking of flat moieties, hydrophobic interaction, electrostatic, and van der Waals interactions. Advancements in Systematic Evolution of Ligands by Exponential Enrichment (SELEX) assay has created the opportunity to artificially generate aptamers that specifically bind to desired cancer and tumor surface receptors with high affinities. This article discusses the potential application of molecular dynamics (MD) simulation to advance aptamer‐mediated receptor targeting in targeted cancer therapy. MD simulation offers real‐time analysis of the molecular drivers of the aptamer‐receptor binding and generate optimal receptor binding conditions for theranostic applications. The article also provides an overview of different cancer types with focus on receptor biomarking and targeted treatment approaches, conventional molecular probes, and aptamers that have been explored for cancer cells targeting.

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A 5-Enolpyruvylshikimate 3-Phosphate Synthase Functions as a Transcriptional Repressor in Populus

Cited by 68 publications

References 81 publications

A Molecular Blueprint of Lignin Repression

A Molecular Blueprint of Lignin Repression

Do plants pay a fitness cost to be resistant to glyphosate?

Advancing Aptamers as Molecular Probes for Cancer Theranostic Applications—The Role of Molecular Dynamics Simulation

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