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Tri-Hydroxy-Triacylglycerol Is Efficiently Produced by Position-Specific Castor Acyltransferases.
Plant Physiol. 2019 03; 179(3):1050-1063.PP

Abstract

Understanding the biochemistry of triacylglycerol (TAG) assembly is critical in tailoring seed oils to produce high-value products. Hydroxy-fatty acid (HFA) is one such valuable modified fatty acid, which can be produced at low levels in Arabidopsis (Arabidopsis thaliana) seed through transgenic expression of the castor (Ricinus communis) hydroxylase. The resulting plants have low seed oil content and poor seedling establishment, indicating that Arabidopsis lacks efficient metabolic networks for biosynthesis and catabolism of hydroxy-containing TAG. To improve utilization of such substrates, we expressed three castor acyltransferase enzymes that incorporate HFA at each stereochemical position during TAG synthesis. This produced abundant tri-HFA TAG and concentrated 44% of seed HFA moieties into this one TAG species. Ricinoleic acid was more abundant than any other fatty acid in these seeds, which had 3-fold more HFA by weight than that in seeds following simple hydroxylase expression, the highest yet measured in a nonnative plant. Efficient utilization of hydroxy-containing lipid substrates increased the rate of TAG synthesis 2-fold, leading to complete relief of the low-oil phenotype. Partition of HFA into specific TAG molecules increased the storage lipid available for mobilization during seedling development, resulting in a 1.9-fold increase in seedling establishment. Expression of a complete acyltransferase pathway to efficiently process HFA establishes a benchmark in the quest to successfully produce modified oils in plants.

Authors+Show Affiliations

Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340.Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340.Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340 jab@wsu.edu.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

30610110

Citation

Lunn, Daniel, et al. "Tri-Hydroxy-Triacylglycerol Is Efficiently Produced By Position-Specific Castor Acyltransferases." Plant Physiology, vol. 179, no. 3, 2019, pp. 1050-1063.
Lunn D, Wallis JG, Browse J. Tri-Hydroxy-Triacylglycerol Is Efficiently Produced by Position-Specific Castor Acyltransferases. Plant Physiol. 2019;179(3):1050-1063.
Lunn, D., Wallis, J. G., & Browse, J. (2019). Tri-Hydroxy-Triacylglycerol Is Efficiently Produced by Position-Specific Castor Acyltransferases. Plant Physiology, 179(3), 1050-1063. https://doi.org/10.1104/pp.18.01409
Lunn D, Wallis JG, Browse J. Tri-Hydroxy-Triacylglycerol Is Efficiently Produced By Position-Specific Castor Acyltransferases. Plant Physiol. 2019;179(3):1050-1063. PubMed PMID: 30610110.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Tri-Hydroxy-Triacylglycerol Is Efficiently Produced by Position-Specific Castor Acyltransferases. AU - Lunn,Daniel, AU - Wallis,James G, AU - Browse,John, Y1 - 2019/01/04/ PY - 2018/11/09/received PY - 2018/12/21/accepted PY - 2019/1/6/pubmed PY - 2019/6/5/medline PY - 2019/1/6/entrez SP - 1050 EP - 1063 JF - Plant physiology JO - Plant Physiol VL - 179 IS - 3 N2 - Understanding the biochemistry of triacylglycerol (TAG) assembly is critical in tailoring seed oils to produce high-value products. Hydroxy-fatty acid (HFA) is one such valuable modified fatty acid, which can be produced at low levels in Arabidopsis (Arabidopsis thaliana) seed through transgenic expression of the castor (Ricinus communis) hydroxylase. The resulting plants have low seed oil content and poor seedling establishment, indicating that Arabidopsis lacks efficient metabolic networks for biosynthesis and catabolism of hydroxy-containing TAG. To improve utilization of such substrates, we expressed three castor acyltransferase enzymes that incorporate HFA at each stereochemical position during TAG synthesis. This produced abundant tri-HFA TAG and concentrated 44% of seed HFA moieties into this one TAG species. Ricinoleic acid was more abundant than any other fatty acid in these seeds, which had 3-fold more HFA by weight than that in seeds following simple hydroxylase expression, the highest yet measured in a nonnative plant. Efficient utilization of hydroxy-containing lipid substrates increased the rate of TAG synthesis 2-fold, leading to complete relief of the low-oil phenotype. Partition of HFA into specific TAG molecules increased the storage lipid available for mobilization during seedling development, resulting in a 1.9-fold increase in seedling establishment. Expression of a complete acyltransferase pathway to efficiently process HFA establishes a benchmark in the quest to successfully produce modified oils in plants. SN - 1532-2548 UR - https://www.unboundmedicine.com/medline/citation/30610110/Tri_Hydroxy_Triacylglycerol_Is_Efficiently_Produced_by_Position_Specific_Castor_Acyltransferases_ L2 - http://www.plantphysiol.org/lookup/pmidlookup?view=long&pmid=30610110 DB - PRIME DP - Unbound Medicine ER -