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United States Department of Agriculture

Agricultural Research Service

Research Project: MOLECULAR AND GENETIC ENHANCEMENT OF ABIOTIC STRESS TOLERANCE IN SORGHUM Title: An enzyme regulating triacylglycerol composition is encoded by the ROD1 gene of Arabidopsis

Authors
item Lu, Chaofu -
item Xin, Zhanguo
item Ren, Zhonghai -
item Miquel, Martine -
item Browse, John -

Submitted to: Proceedings of the National Academy of Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 11, 2009
Publication Date: November 3, 2009
Citation: Lu, C., Xin, Z., Ren, Z., Miquel, M., Browse, J. 2009. An enzyme regulating triacylglycerol composition is encoded by the ROD1 gene of Arabidopsis. Proceedings of the National Academy of Sciences. 106(44):18837-18842.

Interpretive Summary: The polyunsaturated fatty acids (PUFAs), linoleic (18:2) and '-linolenic (18:3), in triacylglycerols (TAG) influence the adaptability of plants to abiotic stresses and are also major factors that affect the quality of plant oils for human health, as well as for biofuels and other renewable applications. These PUFAs are essential fatty acids for animals and plants, but they are also the source of unhealthy trans fats during processing of many foodstuffs. 18:2 and 18:3 are synthesized in developing seeds by desaturation of oleic acid (18:1) esterified on the membrane lipid phosphatidylcholine (PC) on the endoplasmic reticulum. However, the reactions and fluxes involved in this metabolism are not completely known. Here, we show that a previously unrecognized enzyme, phosphatidylcholine:diacylglycerol cholinephosphotransferase (PDCT), encoded by the Arabidopsis ROD1 gene, is a major route by which 18:1 enters PC for desaturation. The PDCT enzyme catalyzes transfer of the phosphocholine headgroup from PC to diacylglycerol, and mutation of rod1 reduces 18:2 and 18:3 accumulation in seed TAG by 40%. Our discovery of PDCT is important for understanding glycerolipid metabolism in plants and other organisms, and provides new tools to modify the fatty acid compositions of plant oils for improved nutrition, biofuel, and abiotic stress tolerance.

Technical Abstract: The polyunsaturated fatty acids (PUFAs), linoleic (18:2) and '-linolenic (18:3), in triacylglycerols (TAG) are major factors that affect the quality of plant oils for human health, as well as for biofuels and other renewable applications. These PUFAs are essential fatty acids for animals and plants, but they are also the source of unhealthy trans fats during processing of many foodstuffs. 18:2 and 18:3 are synthesized in developing seeds by desaturation of oleic acid (18:1) esterified on the membrane lipid phosphatidylcholine (PC) on the endoplasmic reticulum. However, the reactions and fluxes involved in this metabolism are not completely known. Here, we show that a previously unrecognized enzyme, phosphatidylcholine:diacylglycerol cholinephosphotransferase (PDCT), encoded by the Arabidopsis ROD1 gene, is a major route by which 18:1 enters PC for desaturation. The PDCT enzyme catalyzes transfer of the phosphocholine headgroup from PC to diacylglycerol, and mutation of rod1 reduces 18:2 and 18:3 accumulation in seed TAG by 40%. Our discovery of PDCT is important for understanding glycerolipid metabolism in plants and other organisms, and provides new tools to modify the fatty acid compositions of plant oils for improved nutrition, biofuel and other purposes.

Last Modified: 10/25/2014
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