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Transgenic increases in seed oil content are associated with the differential expression of novel Brassica-specific transcripts

BACKGROUND: Seed oil accumulates primarily as triacylglycerol (TAG). While the biochemical pathway for TAG biosynthesis is known, its regulation remains unclear. Previous research identified microsomal diacylglycerol acyltransferase 1 (DGAT1, EC 2.3.1.20) as controlling a rate-limiting step in the T...

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Autores principales: Sharma, Nirmala, Anderson, Maureen, Kumar, Arvind, Zhang, Yan, Giblin, E Michael, Abrams, Suzanne R, Zaharia, L Irina, Taylor, David C, Fobert, Pierre R
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2008
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2627897/
https://www.ncbi.nlm.nih.gov/pubmed/19099582
http://dx.doi.org/10.1186/1471-2164-9-619
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author Sharma, Nirmala
Anderson, Maureen
Kumar, Arvind
Zhang, Yan
Giblin, E Michael
Abrams, Suzanne R
Zaharia, L Irina
Taylor, David C
Fobert, Pierre R
author_facet Sharma, Nirmala
Anderson, Maureen
Kumar, Arvind
Zhang, Yan
Giblin, E Michael
Abrams, Suzanne R
Zaharia, L Irina
Taylor, David C
Fobert, Pierre R
author_sort Sharma, Nirmala
collection PubMed
description BACKGROUND: Seed oil accumulates primarily as triacylglycerol (TAG). While the biochemical pathway for TAG biosynthesis is known, its regulation remains unclear. Previous research identified microsomal diacylglycerol acyltransferase 1 (DGAT1, EC 2.3.1.20) as controlling a rate-limiting step in the TAG biosynthesis pathway. Of note, overexpression of DGAT1 results in substantial increases in oil content and seed size. To further analyze the global consequences of manipulating DGAT1 levels during seed development, a concerted transcriptome and metabolome analysis of transgenic B. napus prototypes was performed. RESULTS: Using a targeted Brassica cDNA microarray, about 200 genes were differentially expressed in two independent transgenic lines analyzed. Interestingly, 24–33% of the targets showing significant changes have no matching gene in Arabidopsis although these represent only 5% of the targets on the microarray. Further analysis of some of these novel transcripts indicated that several are inducible by ABA in microspore-derived embryos. Of the 200 Arabidopsis genes implicated in lipid biology present on the microarray, 36 were found to be differentially regulated in DGAT transgenic lines. Furthermore, kinetic reverse transcriptase Polymerase Chain Reaction (k-PCR) analysis revealed up-regulation of genes encoding enzymes of the Kennedy pathway involved in assembly of TAGs. Hormone profiling indicated that levels of auxins and cytokinins varied between transgenic lines and untransformed controls, while differences in the pool sizes of ABA and catabolites were only observed at later stages of development. CONCLUSION: Our results indicate that the increased TAG accumulation observed in transgenic DGAT1 plants is associated with modest transcriptional and hormonal changes during seed development that are not limited to the TAG biosynthesis pathway. These might be associated with feedback or feed-forward effects due to altered levels of DGAT1 activity. The fact that a large fraction of significant amplicons have no matching genes in Arabidopsis compromised our ability to draw concrete inferences from the data at this stage, but has led to the identification of novel genes of potential interest.
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spelling pubmed-26278972009-01-17 Transgenic increases in seed oil content are associated with the differential expression of novel Brassica-specific transcripts Sharma, Nirmala Anderson, Maureen Kumar, Arvind Zhang, Yan Giblin, E Michael Abrams, Suzanne R Zaharia, L Irina Taylor, David C Fobert, Pierre R BMC Genomics Research Article BACKGROUND: Seed oil accumulates primarily as triacylglycerol (TAG). While the biochemical pathway for TAG biosynthesis is known, its regulation remains unclear. Previous research identified microsomal diacylglycerol acyltransferase 1 (DGAT1, EC 2.3.1.20) as controlling a rate-limiting step in the TAG biosynthesis pathway. Of note, overexpression of DGAT1 results in substantial increases in oil content and seed size. To further analyze the global consequences of manipulating DGAT1 levels during seed development, a concerted transcriptome and metabolome analysis of transgenic B. napus prototypes was performed. RESULTS: Using a targeted Brassica cDNA microarray, about 200 genes were differentially expressed in two independent transgenic lines analyzed. Interestingly, 24–33% of the targets showing significant changes have no matching gene in Arabidopsis although these represent only 5% of the targets on the microarray. Further analysis of some of these novel transcripts indicated that several are inducible by ABA in microspore-derived embryos. Of the 200 Arabidopsis genes implicated in lipid biology present on the microarray, 36 were found to be differentially regulated in DGAT transgenic lines. Furthermore, kinetic reverse transcriptase Polymerase Chain Reaction (k-PCR) analysis revealed up-regulation of genes encoding enzymes of the Kennedy pathway involved in assembly of TAGs. Hormone profiling indicated that levels of auxins and cytokinins varied between transgenic lines and untransformed controls, while differences in the pool sizes of ABA and catabolites were only observed at later stages of development. CONCLUSION: Our results indicate that the increased TAG accumulation observed in transgenic DGAT1 plants is associated with modest transcriptional and hormonal changes during seed development that are not limited to the TAG biosynthesis pathway. These might be associated with feedback or feed-forward effects due to altered levels of DGAT1 activity. The fact that a large fraction of significant amplicons have no matching genes in Arabidopsis compromised our ability to draw concrete inferences from the data at this stage, but has led to the identification of novel genes of potential interest. BioMed Central 2008-12-19 /pmc/articles/PMC2627897/ /pubmed/19099582 http://dx.doi.org/10.1186/1471-2164-9-619 Text en Copyright © 2008 Sharma et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( (http://creativecommons.org/licenses/by/2.0) ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Sharma, Nirmala
Anderson, Maureen
Kumar, Arvind
Zhang, Yan
Giblin, E Michael
Abrams, Suzanne R
Zaharia, L Irina
Taylor, David C
Fobert, Pierre R
Transgenic increases in seed oil content are associated with the differential expression of novel Brassica-specific transcripts
title Transgenic increases in seed oil content are associated with the differential expression of novel Brassica-specific transcripts
title_full Transgenic increases in seed oil content are associated with the differential expression of novel Brassica-specific transcripts
title_fullStr Transgenic increases in seed oil content are associated with the differential expression of novel Brassica-specific transcripts
title_full_unstemmed Transgenic increases in seed oil content are associated with the differential expression of novel Brassica-specific transcripts
title_short Transgenic increases in seed oil content are associated with the differential expression of novel Brassica-specific transcripts
title_sort transgenic increases in seed oil content are associated with the differential expression of novel brassica-specific transcripts
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2627897/
https://www.ncbi.nlm.nih.gov/pubmed/19099582
http://dx.doi.org/10.1186/1471-2164-9-619
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