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Structural characterization of highly glucosylated crocins and regulation of their biosynthesis during flower development in Crocus

Crocin biosynthesis in Crocus has been proposed to proceed through a zeaxanthin cleavage pathway catalyzed by carotenoid cleavage dioxygenase 2 (CCD2), and followed by glucosylation reactions catalyzed by CsGT2 (UGT74AD1). In Crocus ancyrensis flowers, crocins with eight (crocin-1), seven (crocin-2)...

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Autores principales: Ahrazem, Oussama, Rubio-Moraga, Angela, Jimeno, Maria L., Gómez-Gómez, Lourdes
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4632010/
https://www.ncbi.nlm.nih.gov/pubmed/26582258
http://dx.doi.org/10.3389/fpls.2015.00971
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author Ahrazem, Oussama
Rubio-Moraga, Angela
Jimeno, Maria L.
Gómez-Gómez, Lourdes
author_facet Ahrazem, Oussama
Rubio-Moraga, Angela
Jimeno, Maria L.
Gómez-Gómez, Lourdes
author_sort Ahrazem, Oussama
collection PubMed
description Crocin biosynthesis in Crocus has been proposed to proceed through a zeaxanthin cleavage pathway catalyzed by carotenoid cleavage dioxygenase 2 (CCD2), and followed by glucosylation reactions catalyzed by CsGT2 (UGT74AD1). In Crocus ancyrensis flowers, crocins with eight (crocin-1), seven (crocin-2), and six glucose (crocin-3) moieties accumulated both in stigma and tepals. We have characterized the structure of these highly glucosylated crocins and follow up their accumulation by high-resolution liquid chromatography coupled with diode array detector along the development of both tissues, and coupled to the isolation and analysis of the expression of eighteen genes (PSY-I, PSY-II, PDS-(I-V), ISO-ZDS, ZDS, CtrISO, LYC-I and II, BCH, CaCCD2, UGT74AD2-5) related with the apocarotenoid metabolism in C. ancyrensis tepals and stigmas. Structure elucidation of crocin-1 and crocin-2 was done by the combined use of 1D and 2D [(1)H, (1)H] (gCOSY and TOCSY and ROESY) and [(1)H-(13)C] NMR experiments, revealing that for crocin-1 was all-trans-crocetin O-[β-D- Glucopyranosyl)-(1→4)-(β-D-glucopyranosyl)-(1→2)]-O-[β-D-glucopyranosyl-(1→6)]-β-D-glucopyranosyl diester, while crocin-2 showed an identical structure except for the absence of one glucose residue in one end of the molecule. Crocins accumulation was not synchronically regulated in stigma and tepals, although in both cases crocins accumulation parallels tissue development, decreasing at anthesis. The expression of the carotenogenic genes PSY, ZDS-V, BCH, and LCY-II was correlated with crocins accumulation. In addition, CaCCD2 and only one of the four glucosyltransferase encoding genes, UGT74AD2, were highly expressed, and the expression was correlated with high levels of crocins accumulation in stigma and tepals.
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spelling pubmed-46320102015-11-18 Structural characterization of highly glucosylated crocins and regulation of their biosynthesis during flower development in Crocus Ahrazem, Oussama Rubio-Moraga, Angela Jimeno, Maria L. Gómez-Gómez, Lourdes Front Plant Sci Plant Science Crocin biosynthesis in Crocus has been proposed to proceed through a zeaxanthin cleavage pathway catalyzed by carotenoid cleavage dioxygenase 2 (CCD2), and followed by glucosylation reactions catalyzed by CsGT2 (UGT74AD1). In Crocus ancyrensis flowers, crocins with eight (crocin-1), seven (crocin-2), and six glucose (crocin-3) moieties accumulated both in stigma and tepals. We have characterized the structure of these highly glucosylated crocins and follow up their accumulation by high-resolution liquid chromatography coupled with diode array detector along the development of both tissues, and coupled to the isolation and analysis of the expression of eighteen genes (PSY-I, PSY-II, PDS-(I-V), ISO-ZDS, ZDS, CtrISO, LYC-I and II, BCH, CaCCD2, UGT74AD2-5) related with the apocarotenoid metabolism in C. ancyrensis tepals and stigmas. Structure elucidation of crocin-1 and crocin-2 was done by the combined use of 1D and 2D [(1)H, (1)H] (gCOSY and TOCSY and ROESY) and [(1)H-(13)C] NMR experiments, revealing that for crocin-1 was all-trans-crocetin O-[β-D- Glucopyranosyl)-(1→4)-(β-D-glucopyranosyl)-(1→2)]-O-[β-D-glucopyranosyl-(1→6)]-β-D-glucopyranosyl diester, while crocin-2 showed an identical structure except for the absence of one glucose residue in one end of the molecule. Crocins accumulation was not synchronically regulated in stigma and tepals, although in both cases crocins accumulation parallels tissue development, decreasing at anthesis. The expression of the carotenogenic genes PSY, ZDS-V, BCH, and LCY-II was correlated with crocins accumulation. In addition, CaCCD2 and only one of the four glucosyltransferase encoding genes, UGT74AD2, were highly expressed, and the expression was correlated with high levels of crocins accumulation in stigma and tepals. Frontiers Media S.A. 2015-11-04 /pmc/articles/PMC4632010/ /pubmed/26582258 http://dx.doi.org/10.3389/fpls.2015.00971 Text en Copyright © 2015 Ahrazem, Rubio-Moraga, Jimeno and Gómez-Gómez. http://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) or licensor 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
Ahrazem, Oussama
Rubio-Moraga, Angela
Jimeno, Maria L.
Gómez-Gómez, Lourdes
Structural characterization of highly glucosylated crocins and regulation of their biosynthesis during flower development in Crocus
title Structural characterization of highly glucosylated crocins and regulation of their biosynthesis during flower development in Crocus
title_full Structural characterization of highly glucosylated crocins and regulation of their biosynthesis during flower development in Crocus
title_fullStr Structural characterization of highly glucosylated crocins and regulation of their biosynthesis during flower development in Crocus
title_full_unstemmed Structural characterization of highly glucosylated crocins and regulation of their biosynthesis during flower development in Crocus
title_short Structural characterization of highly glucosylated crocins and regulation of their biosynthesis during flower development in Crocus
title_sort structural characterization of highly glucosylated crocins and regulation of their biosynthesis during flower development in crocus
topic Plant Science
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4632010/
https://www.ncbi.nlm.nih.gov/pubmed/26582258
http://dx.doi.org/10.3389/fpls.2015.00971
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