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Increased DHA Production in Seed Oil Using a Selective Lysophosphatidic Acid Acyltransferase
Metabolic engineering of the omega-3 (ω3) long chain polyunsaturated fatty acid biosynthesis pathway has generated fish oil-like levels of pharmaceutically and nutritionally important docosahexaenoic acid (DHA) in plant seeds. However, the majority of DHA has been accumulated at the sn-1 and sn-3 po...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Frontiers Media S.A.
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6113368/ https://www.ncbi.nlm.nih.gov/pubmed/30186303 http://dx.doi.org/10.3389/fpls.2018.01234 |
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author | Shrestha, Pushkar Hussain, Dawar Mulder, Roger J. Taylor, Matthew C. Singh, Surinder P. Petrie, James R. Zhou, Xue-Rong |
author_facet | Shrestha, Pushkar Hussain, Dawar Mulder, Roger J. Taylor, Matthew C. Singh, Surinder P. Petrie, James R. Zhou, Xue-Rong |
author_sort | Shrestha, Pushkar |
collection | PubMed |
description | Metabolic engineering of the omega-3 (ω3) long chain polyunsaturated fatty acid biosynthesis pathway has generated fish oil-like levels of pharmaceutically and nutritionally important docosahexaenoic acid (DHA) in plant seeds. However, the majority of DHA has been accumulated at the sn-1 and sn-3 positions of triacylglycerol (TAG) in these engineered seeds, leaving only a minor amount (∼10%) at sn-2 position and indicating a strong discrimination (or, a very poor specificity) for DHA by seed lysophosphatidic acid acyltransferases (LPAATs), which mediate the acylation of sn-2 position of glycerol backbone. In order to increase the level of DHA at sn-2 position of TAG and to increase overall DHA level in seeds, we attempted to discover DHA-preferring LPAATs. Several LPAATs for acylation of the sn-2 position of the TAG glycerol backbone were investigated for substrate preference for DHA. In transiently expressing these LPAATs in Nicotiana benthamiana, a Mortierella alpina LPAAT had the highest substrate specificity for accumulating DHA onto oleoyl-lysophosphatidic acid (oleoyl-LPA), while the plant LPAATs tested showed lower preference for DHA. In a competition assay with a pool of four ω3 acyl-Coenzyme A (CoA) substrates involved in the DHA biosynthesis pathway, LPAATs from both M. alpina and Emiliania huxleyi showed a high preference for DHA-CoA acylation onto oleoyl-LPA. When docosahexaenoyl-LPA was used as the acyl receiver, M. alpina LPAAT also showed a high preference for DHA-CoA. Stable overexpression of M. alpina LPAAT in an Arabidopsis line that expressed the DHA biosynthesis pathway significantly increased both the total DHA levels and the distribution of DHA onto the sn-2 position of seed TAG. LC-MS analysis of the seed TAG species also confirmed that overexpression of M. alpina LPAAT increased di-DHA and tri-DHA TAGs, suggesting that the M. alpina LPAAT could enrich DHA at the TAG sn-2 position, leading to a metabolic engineering of oil seed for channeling DHA into the sn-2 position of TAG and to a higher DHA level. |
format | Online Article Text |
id | pubmed-6113368 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-61133682018-09-05 Increased DHA Production in Seed Oil Using a Selective Lysophosphatidic Acid Acyltransferase Shrestha, Pushkar Hussain, Dawar Mulder, Roger J. Taylor, Matthew C. Singh, Surinder P. Petrie, James R. Zhou, Xue-Rong Front Plant Sci Plant Science Metabolic engineering of the omega-3 (ω3) long chain polyunsaturated fatty acid biosynthesis pathway has generated fish oil-like levels of pharmaceutically and nutritionally important docosahexaenoic acid (DHA) in plant seeds. However, the majority of DHA has been accumulated at the sn-1 and sn-3 positions of triacylglycerol (TAG) in these engineered seeds, leaving only a minor amount (∼10%) at sn-2 position and indicating a strong discrimination (or, a very poor specificity) for DHA by seed lysophosphatidic acid acyltransferases (LPAATs), which mediate the acylation of sn-2 position of glycerol backbone. In order to increase the level of DHA at sn-2 position of TAG and to increase overall DHA level in seeds, we attempted to discover DHA-preferring LPAATs. Several LPAATs for acylation of the sn-2 position of the TAG glycerol backbone were investigated for substrate preference for DHA. In transiently expressing these LPAATs in Nicotiana benthamiana, a Mortierella alpina LPAAT had the highest substrate specificity for accumulating DHA onto oleoyl-lysophosphatidic acid (oleoyl-LPA), while the plant LPAATs tested showed lower preference for DHA. In a competition assay with a pool of four ω3 acyl-Coenzyme A (CoA) substrates involved in the DHA biosynthesis pathway, LPAATs from both M. alpina and Emiliania huxleyi showed a high preference for DHA-CoA acylation onto oleoyl-LPA. When docosahexaenoyl-LPA was used as the acyl receiver, M. alpina LPAAT also showed a high preference for DHA-CoA. Stable overexpression of M. alpina LPAAT in an Arabidopsis line that expressed the DHA biosynthesis pathway significantly increased both the total DHA levels and the distribution of DHA onto the sn-2 position of seed TAG. LC-MS analysis of the seed TAG species also confirmed that overexpression of M. alpina LPAAT increased di-DHA and tri-DHA TAGs, suggesting that the M. alpina LPAAT could enrich DHA at the TAG sn-2 position, leading to a metabolic engineering of oil seed for channeling DHA into the sn-2 position of TAG and to a higher DHA level. Frontiers Media S.A. 2018-08-22 /pmc/articles/PMC6113368/ /pubmed/30186303 http://dx.doi.org/10.3389/fpls.2018.01234 Text en Copyright © 2018 Shrestha, Hussain, Mulder, Taylor, Singh, Petrie and Zhou. 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) 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 Shrestha, Pushkar Hussain, Dawar Mulder, Roger J. Taylor, Matthew C. Singh, Surinder P. Petrie, James R. Zhou, Xue-Rong Increased DHA Production in Seed Oil Using a Selective Lysophosphatidic Acid Acyltransferase |
title | Increased DHA Production in Seed Oil Using a Selective Lysophosphatidic Acid Acyltransferase |
title_full | Increased DHA Production in Seed Oil Using a Selective Lysophosphatidic Acid Acyltransferase |
title_fullStr | Increased DHA Production in Seed Oil Using a Selective Lysophosphatidic Acid Acyltransferase |
title_full_unstemmed | Increased DHA Production in Seed Oil Using a Selective Lysophosphatidic Acid Acyltransferase |
title_short | Increased DHA Production in Seed Oil Using a Selective Lysophosphatidic Acid Acyltransferase |
title_sort | increased dha production in seed oil using a selective lysophosphatidic acid acyltransferase |
topic | Plant Science |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6113368/ https://www.ncbi.nlm.nih.gov/pubmed/30186303 http://dx.doi.org/10.3389/fpls.2018.01234 |
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