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CTP Synthase 2 From Arabidopsis thaliana Is Required for Complete Embryo Development

Pyrimidine de novo synthesis is an essential pathway in all organisms. The final and rate-limiting step in the synthesis of the nucleotide cytidine triphosphate (CTP) is catalyzed by CTP synthase (CTPS), and Arabidopsis harbors five isoforms. Single mutant lines defective in each one of the four iso...

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Autores principales: Hickl, Daniel, Scheuring, David, Möhlmann, Torsten
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8082242/
https://www.ncbi.nlm.nih.gov/pubmed/33936137
http://dx.doi.org/10.3389/fpls.2021.652434
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author Hickl, Daniel
Scheuring, David
Möhlmann, Torsten
author_facet Hickl, Daniel
Scheuring, David
Möhlmann, Torsten
author_sort Hickl, Daniel
collection PubMed
description Pyrimidine de novo synthesis is an essential pathway in all organisms. The final and rate-limiting step in the synthesis of the nucleotide cytidine triphosphate (CTP) is catalyzed by CTP synthase (CTPS), and Arabidopsis harbors five isoforms. Single mutant lines defective in each one of the four isoforms do not show apparent phenotypical alterations in comparison to wild-type plants. However, Arabidopsis lines that contain T-DNA insertions in the CTPS2 gene were unable to produce homozygous offspring. Here, we show that CTPS2 exhibits a distinct expression pattern throughout embryo development, and loss-of-function mutants are embryo lethal, as siliques from +/ctps2 plants contained nearly 25% aborted seeds. This phenotype was rescued by complementation with CTPS2 under control of its endogenous promoter. CTPS2::GFP lines revealed expression only in the tip of columella cells in embryo root tips of the heart and later stages. Furthermore, CTPS2 expression in mature roots, most pronounced in the columella cells, shoots, and vasculature tissue of young seedlings, was observed. Filial generations of +/ctps2 plants did not germinate properly, even under external cytidine supply. During embryo development, the CTPS2 expression pattern resembled the established auxin reporter DR5::GFP. Indeed, the cloned promoter region we used in this study possesses a repeat of an auxin response element, and auxin supply increased CTPS2 expression in a cell-type-specific manner. Thus, we conclude that CTPS2 is essential for CTP supply in developing embryos, and loss-of-function mutants in CTPS2 are embryo lethal.
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spelling pubmed-80822422021-04-30 CTP Synthase 2 From Arabidopsis thaliana Is Required for Complete Embryo Development Hickl, Daniel Scheuring, David Möhlmann, Torsten Front Plant Sci Plant Science Pyrimidine de novo synthesis is an essential pathway in all organisms. The final and rate-limiting step in the synthesis of the nucleotide cytidine triphosphate (CTP) is catalyzed by CTP synthase (CTPS), and Arabidopsis harbors five isoforms. Single mutant lines defective in each one of the four isoforms do not show apparent phenotypical alterations in comparison to wild-type plants. However, Arabidopsis lines that contain T-DNA insertions in the CTPS2 gene were unable to produce homozygous offspring. Here, we show that CTPS2 exhibits a distinct expression pattern throughout embryo development, and loss-of-function mutants are embryo lethal, as siliques from +/ctps2 plants contained nearly 25% aborted seeds. This phenotype was rescued by complementation with CTPS2 under control of its endogenous promoter. CTPS2::GFP lines revealed expression only in the tip of columella cells in embryo root tips of the heart and later stages. Furthermore, CTPS2 expression in mature roots, most pronounced in the columella cells, shoots, and vasculature tissue of young seedlings, was observed. Filial generations of +/ctps2 plants did not germinate properly, even under external cytidine supply. During embryo development, the CTPS2 expression pattern resembled the established auxin reporter DR5::GFP. Indeed, the cloned promoter region we used in this study possesses a repeat of an auxin response element, and auxin supply increased CTPS2 expression in a cell-type-specific manner. Thus, we conclude that CTPS2 is essential for CTP supply in developing embryos, and loss-of-function mutants in CTPS2 are embryo lethal. Frontiers Media S.A. 2021-04-15 /pmc/articles/PMC8082242/ /pubmed/33936137 http://dx.doi.org/10.3389/fpls.2021.652434 Text en Copyright © 2021 Hickl, Scheuring and Möhlmann. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Plant Science
Hickl, Daniel
Scheuring, David
Möhlmann, Torsten
CTP Synthase 2 From Arabidopsis thaliana Is Required for Complete Embryo Development
title CTP Synthase 2 From Arabidopsis thaliana Is Required for Complete Embryo Development
title_full CTP Synthase 2 From Arabidopsis thaliana Is Required for Complete Embryo Development
title_fullStr CTP Synthase 2 From Arabidopsis thaliana Is Required for Complete Embryo Development
title_full_unstemmed CTP Synthase 2 From Arabidopsis thaliana Is Required for Complete Embryo Development
title_short CTP Synthase 2 From Arabidopsis thaliana Is Required for Complete Embryo Development
title_sort ctp synthase 2 from arabidopsis thaliana is required for complete embryo development
topic Plant Science
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8082242/
https://www.ncbi.nlm.nih.gov/pubmed/33936137
http://dx.doi.org/10.3389/fpls.2021.652434
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