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Shockey J, Lager I, Stymne S, Kotapati HK, Sheffield J, Mason C, Bates PD. Specialized lysophosphatidic acid acyltransferases contribute to unusual fatty acid accumulation in exotic Euphorbiaceae seed oils. PLANTA 2019; 249:1285-1299. [PMID: 30610363 DOI: 10.1007/s00425-018-03086-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 12/29/2018] [Indexed: 05/20/2023]
Abstract
In vivo and in vitro analyses of Euphorbiaceae species' triacylglycerol assembly enzymes substrate selectivity are consistent with the co-evolution of seed-specific unusual fatty acid production and suggest that many of these genes will be useful for biotechnological production of designer oils. Many exotic Euphorbiaceae species, including tung tree (Vernicia fordii), castor bean (Ricinus communis), Bernardia pulchella, and Euphorbia lagascae, accumulate unusual fatty acids in their seed oils, many of which have valuable properties for the chemical industry. However, various adverse plant characteristics including low seed yields, production of toxic compounds, limited growth range, and poor resistance to abiotic stresses have limited full agronomic exploitation of these plants. Biotechnological production of these unusual fatty acids (UFA) in high yielding non-food oil crops would provide new robust sources for these valuable bio-chemicals. Previous research has shown that expression of the primary UFA biosynthetic gene alone is not enough for high-level accumulation in transgenic seed oils; other genes must be included to drive selective UFA incorporation into oils. Here, we use a series of in planta molecular genetic studies and in vitro biochemical measurements to demonstrate that lysophosphatidic acid acyltransferases from two Euphorbiaceae species have high selectivity for incorporation of their respective unusual fatty acids into the phosphatidic acid intermediate of oil biosynthesis. These results are consistent with the hypothesis that unusual fatty acid accumulation arose in part via co-evolution of multiple oil biosynthesis and assembly enzymes that cooperate to enhance selective fatty acid incorporation into seed oils over that of the common fatty acids found in membrane lipids.
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Affiliation(s)
- Jay Shockey
- United States Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, 70124, USA
| | - Ida Lager
- Department of Plant Breeding, Swedish University of Agricultural Sciences, 230 53, Alnarp, Sweden
| | - Sten Stymne
- Department of Plant Breeding, Swedish University of Agricultural Sciences, 230 53, Alnarp, Sweden
| | - Hari Kiran Kotapati
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA
| | - Jennifer Sheffield
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
| | - Catherine Mason
- United States Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, New Orleans, LA, 70124, USA
| | - Philip D Bates
- Department of Chemistry and Biochemistry, University of Southern Mississippi, Hattiesburg, MS, 39406, USA.
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA.
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Horn PJ, Liu J, Cocuron JC, McGlew K, Thrower NA, Larson M, Lu C, Alonso AP, Ohlrogge J. Identification of multiple lipid genes with modifications in expression and sequence associated with the evolution of hydroxy fatty acid accumulation in Physaria fendleri. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 86:322-348. [PMID: 26991237 DOI: 10.1111/tpj.13163] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 03/02/2016] [Accepted: 03/07/2016] [Indexed: 06/05/2023]
Abstract
Two Brassicaceae species, Physaria fendleri and Camelina sativa, are genetically very closely related to each other and to Arabidopsis thaliana. Physaria fendleri seeds contain over 50% hydroxy fatty acids (HFAs), while Camelina sativa and Arabidopsis do not accumulate HFAs. To better understand how plants evolved new biochemical pathways with the capacity to accumulate high levels of unusual fatty acids, transcript expression and protein sequences of developing seeds of Physaria fendleri, wild-type Camelina sativa, and Camelina sativa expressing a castor bean (Ricinus communis) hydroxylase were analyzed. A number of potential evolutionary adaptations within lipid metabolism that probably enhance HFA production and accumulation in Physaria fendleri, and, in their absence, limit accumulation in transgenic tissues were revealed. These adaptations occurred in at least 20 genes within several lipid pathways from the onset of fatty acid synthesis and its regulation to the assembly of triacylglycerols. Lipid genes of Physaria fendleri appear to have co-evolved through modulation of transcriptional abundances and alterations within protein sequences. Only a handful of genes showed evidence for sequence adaptation through gene duplication. Collectively, these evolutionary changes probably occurred to minimize deleterious effects of high HFA amounts and/or to enhance accumulation for physiological advantage. These results shed light on the evolution of pathways for novel fatty acid production in seeds, help explain some of the current limitations to accumulation of HFAs in transgenic plants, and may provide improved strategies for future engineering of their production.
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Affiliation(s)
- Patrick J Horn
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
| | - Jinjie Liu
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, Michigan, USA
| | | | - Kathleen McGlew
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
| | - Nicholas A Thrower
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, Michigan, USA
| | - Matt Larson
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, Michigan, USA
| | - Chaofu Lu
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, Montana, USA
| | - Ana P Alonso
- Department of Molecular Genetics, Ohio State University, Columbus, Ohio, USA
| | - John Ohlrogge
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, Michigan, USA
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