Nucleotide Metabolism in Plants

Witte, Claus-Peter; Herde, Marco

doi:10.1104/pp.19.00955

Cited by 80 publications

(79 citation statements)

References 163 publications

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“…Pyrimidine nucleotides are crucial to plant development and growth as components of nucleic acids and as cofactors in the synthesis of sugars, polysaccharides, glycoproteins and phospholipids 1,2 . However, much remains unknown in plants about the unique organization, regulation, and localization of the enzymes required for de novo biosynthesis of pyrimidines, which are potential targets for crop improvement and weed control 1 . This metabolic pathway starts in the chloroplast, where aspartate transcarbamoylase (ATC) catalyzes the condensation of carbamoyl aspartate from aspartate (Asp) and carbamoyl phosphate (CP) 1,3 (Fig.…”

mentioning

confidence: 99%

UMP inhibition and sequential firing in aspartate transcarbamoylase open ways to regulate plant growth

Bellin

Caño-Ochoa

Velázquez‐Campoy

et al. 2020

Preprint

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Pyrimidine nucleotides are essential to plant development. We proved that Arabidopsis growth can be inhibited or enhanced by down- or upregulating aspartate transcarbamoylase (ATC), the first committed enzyme for de novo biosynthesis of pyrimidines in plants. To understand the unique mechanism of feedback inhibition of this enzyme by uridine 5-monophosphate (UMP), we determined the crystal structure of the Arabidopsis ATC trimer free and bound to UMP, demonstrating that the nucleotide binds and blocks the active site. The regulatory mechanism relies on a loop exclusively conserved in plants, and a single-point mutation (F161A) turns ATC insensitive to UMP. Moreover, the structures in complex with a transition-state analog or with carbamoyl phosphate proved a mechanism in plant ATCs for sequential firing of the active sites. The disclosure of the unique regulatory and catalytic properties suggests new strategies to modulate ATC activity and to control de novo pyrimidine synthesis and plant growth.

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mentioning

confidence: 99%

UMP inhibition and sequential firing in aspartate transcarbamoylase open ways to regulate plant growth

Bellin

Caño-Ochoa

Velázquez‐Campoy

et al. 2020

Preprint

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“…Recovery of cell death with deoxycytidine is mostly likely due to restoring dCTP rather than CTP synthesis, as CTP cannot be synthesized from deoxycytidine without CTPS activity (Witte & Herde, 2020). Furthermore, direct feeding of cytidine was unable to restore cell death to fc2-1 ctps2-5 mutants.…”

Section: Discussionmentioning

confidence: 99%

Chloroplast quality control pathways are dependent on plastid DNA synthesis and nucleotides provided by cytidine triphosphate synthase two

Alamdari

Fisher

Welsh

et al. 2020

Preprint

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Reactive oxygen species (ROS) produced in chloroplasts cause oxidative damage, but also signal to control chloroplast quality control, cell death, and gene expression. The mechanisms behind these pathways remain largely unknown. The Arabidopsis thaliana plastid ferrochelatase two (fc2) mutant produces the ROS singlet oxygen in chloroplasts that activates such signaling pathways. Here we mapped one fc2 suppressor mutation to CYTIDINE TRIPHOSPHATE SYNTHASE TWO (CTPS2), which encodes one of five enzymes in Arabidopsis necessary for cytoplasmic de novo CTP (and dCTP) synthesis. The ctps2 mutation blocks singlet oxygen signals by specifically reducing plastid (not mitochondrial) transcripts and DNA content. These phenotypes are restored by exogenous feeding of the dCTP precursor deoxycytidine, suggesting that ctps2 blocks signaling by limiting nucleotides for plastid genome maintenance. An investigation of CTPS orthologs in Brassicaceae showed that CTPS2 is a member of an ancient lineage distinct from CTPS3. Complementation studies confirmed this analysis; CTPS3 was unable to compensate for CTPS2 function in providing nucleotides for plastid DNA and chloroplast signaling. Our studies link cytoplasmic nucleotide metabolism with chloroplast quality control pathways. Such a connection is achieved by CTPS enzymes that may have evolved specialized functions in providing nucleotides to specific subcellular compartments.

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“…3). It is suggested that the higher content of purine-related metabolites, ribose 5-P and TCA intermediates observed in Socaire, could be contributing to the different enzymatic reactions related with the main pathways associated with energy production and nucleic acid biosynthesis after during seed germination [23,24].…”

Section: Seed Composition Of Landracesmentioning

confidence: 99%

Seed characterization and early nitrogen metabolism performance of seedlings from Altiplano and coastal ecotypes of Quinoa

et al. 2020

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Background: Early seed germination and a functional root system development during establishment are crucial attributes contributing to nutrient competence under marginal nutrient soil conditions. Chenopodium quinoa Willd (Chenopodiaceae) is a rustic crop, able to grow in marginal areas. Altiplano and Coastal/Lowlands are two representative zones of quinoa cultivation in South America with contrasting soil fertility and edaphoclimatic conditions. In the present work, we hypothesize that the ecotypes of Quinoa from Altiplano (landrace Socaire) and from Coastal/Lowland (landrace Faro) have developed differential adaptive responses in order to survive under conditions of low availability of N in their respective climatic zones of Altiplano and Lowlands. In order to understand intrinsic differences for N competence between landraces, seed metabolite profile and germinative capacity were studied. Additionally, in order to elucidate the mechanisms of N uptake and assimilation at limiting N conditions during establishment, germinated seeds of both landraces were grown at either sufficient nitrate (HN) or low nitrate (LN) supply. We studied the photosynthetic performance, protein storage, root morphometrical parameters, activity and expression of N-assimilating enzymes, and the expression of nitrate transporters of roots in plants submitted to the different treatments.

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Nucleotide Metabolism in Plants

Cited by 80 publications

References 163 publications

UMP inhibition and sequential firing in aspartate transcarbamoylase open ways to regulate plant growth

UMP inhibition and sequential firing in aspartate transcarbamoylase open ways to regulate plant growth

Chloroplast quality control pathways are dependent on plastid DNA synthesis and nucleotides provided by cytidine triphosphate synthase two

Seed characterization and early nitrogen metabolism performance of seedlings from Altiplano and coastal ecotypes of Quinoa

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