Functional Analysis of the Brassica napus L. Phytoene Synthase (PSY) Gene Family

Phytoene synthase (PSY) has been shown to catalyze the first committed and rate-limiting step of carotenogenesis in several crop species, including Brassica napus L. Due to its pivotal role, PSY has been a prime target for breeding and metabolic engineering the carotenoid content of seeds, tubers, f...

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Main Authors:	López-Emparán, Ada, Quezada-Martinez, Daniela, Zúñiga-Bustos, Matías, Cifuentes, Víctor, Iñiguez-Luy, Federico, Federico, María Laura
Format:	Online
Language:	English
Published:	Public Library of Science 2014
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4266642/

id	pubmed-4266642
recordtype	oai_dc
spelling	pubmed-42666422014-12-26 Functional Analysis of the Brassica napus L. Phytoene Synthase (PSY) Gene Family López-Emparán, Ada Quezada-Martinez, Daniela Zúñiga-Bustos, Matías Cifuentes, Víctor Iñiguez-Luy, Federico Federico, María Laura Research Article Phytoene synthase (PSY) has been shown to catalyze the first committed and rate-limiting step of carotenogenesis in several crop species, including Brassica napus L. Due to its pivotal role, PSY has been a prime target for breeding and metabolic engineering the carotenoid content of seeds, tubers, fruits and flowers. In Arabidopsis thaliana, PSY is encoded by a single copy gene but small PSY gene families have been described in monocot and dicotyledonous species. We have recently shown that PSY genes have been retained in a triplicated state in the A- and C-Brassica genomes, with each paralogue mapping to syntenic locations in each of the three “Arabidopsis-like” subgenomes. Most importantly, we have shown that in B. napus all six members are expressed, exhibiting overlapping redundancy and signs of subfunctionalization among photosynthetic and non photosynthetic tissues. The question of whether this large PSY family actually encodes six functional enzymes remained to be answered. Therefore, the objectives of this study were to: (i) isolate, characterize and compare the complete protein coding sequences (CDS) of the six B. napus PSY genes; (ii) model their predicted tridimensional enzyme structures; (iii) test their phytoene synthase activity in a heterologous complementation system and (iv) evaluate their individual expression patterns during seed development. This study further confirmed that the six B. napus PSY genes encode proteins with high sequence identity, which have evolved under functional constraint. Structural modeling demonstrated that they share similar tridimensional protein structures with a putative PSY active site. Significantly, all six B. napus PSY enzymes were found to be functional. Taking into account the specific patterns of expression exhibited by these PSY genes during seed development and recent knowledge of PSY suborganellar localization, the selection of transgene candidates for metabolic engineering the carotenoid content of oilseeds is discussed. Public Library of Science 2014-12-15 /pmc/articles/PMC4266642/ /pubmed/25506829 http://dx.doi.org/10.1371/journal.pone.0114878 Text en © 2014 López-Emparán et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	López-Emparán, Ada Quezada-Martinez, Daniela Zúñiga-Bustos, Matías Cifuentes, Víctor Iñiguez-Luy, Federico Federico, María Laura
spellingShingle	López-Emparán, Ada Quezada-Martinez, Daniela Zúñiga-Bustos, Matías Cifuentes, Víctor Iñiguez-Luy, Federico Federico, María Laura Functional Analysis of the Brassica napus L. Phytoene Synthase (PSY) Gene Family
author_facet	López-Emparán, Ada Quezada-Martinez, Daniela Zúñiga-Bustos, Matías Cifuentes, Víctor Iñiguez-Luy, Federico Federico, María Laura
author_sort	López-Emparán, Ada
title	Functional Analysis of the Brassica napus L. Phytoene Synthase (PSY) Gene Family
title_short	Functional Analysis of the Brassica napus L. Phytoene Synthase (PSY) Gene Family
title_full	Functional Analysis of the Brassica napus L. Phytoene Synthase (PSY) Gene Family
title_fullStr	Functional Analysis of the Brassica napus L. Phytoene Synthase (PSY) Gene Family
title_full_unstemmed	Functional Analysis of the Brassica napus L. Phytoene Synthase (PSY) Gene Family
title_sort	functional analysis of the brassica napus l. phytoene synthase (psy) gene family
description	Phytoene synthase (PSY) has been shown to catalyze the first committed and rate-limiting step of carotenogenesis in several crop species, including Brassica napus L. Due to its pivotal role, PSY has been a prime target for breeding and metabolic engineering the carotenoid content of seeds, tubers, fruits and flowers. In Arabidopsis thaliana, PSY is encoded by a single copy gene but small PSY gene families have been described in monocot and dicotyledonous species. We have recently shown that PSY genes have been retained in a triplicated state in the A- and C-Brassica genomes, with each paralogue mapping to syntenic locations in each of the three “Arabidopsis-like” subgenomes. Most importantly, we have shown that in B. napus all six members are expressed, exhibiting overlapping redundancy and signs of subfunctionalization among photosynthetic and non photosynthetic tissues. The question of whether this large PSY family actually encodes six functional enzymes remained to be answered. Therefore, the objectives of this study were to: (i) isolate, characterize and compare the complete protein coding sequences (CDS) of the six B. napus PSY genes; (ii) model their predicted tridimensional enzyme structures; (iii) test their phytoene synthase activity in a heterologous complementation system and (iv) evaluate their individual expression patterns during seed development. This study further confirmed that the six B. napus PSY genes encode proteins with high sequence identity, which have evolved under functional constraint. Structural modeling demonstrated that they share similar tridimensional protein structures with a putative PSY active site. Significantly, all six B. napus PSY enzymes were found to be functional. Taking into account the specific patterns of expression exhibited by these PSY genes during seed development and recent knowledge of PSY suborganellar localization, the selection of transgene candidates for metabolic engineering the carotenoid content of oilseeds is discussed.
publisher	Public Library of Science
publishDate	2014
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4266642/
_version_	1613167691585028096

Functional Analysis of the Brassica napus L. Phytoene Synthase (PSY) Gene Family

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