Abstract

Camelina sativais an emerging biotechnology oil crop. However, more information is needed regarding its innate lipid enzyme specificities. We have therefore characterized several triacylglycerol (TAG) producing enzymes by measuringin vitrosubstrate specificities using different combinations of acyl-acceptors (diacylglycerol, DAG) and donors. Specifically,C. sativaacyl-CoA:diacylglycerol acyltransferase (DGAT) 1 and 2 (which both use acyl-CoA as acyl donor) and phospholipid:diacylglycerol acyltransferase (PDAT, with phosphatidylcoline as acyl donor) were studied. The results show that the DGAT1 and DGAT2 specificities are complementary, with DGAT2 exhibiting a high specificity for acyl acceptors containing only polyunsaturated fatty acids (FAs), whereas DGAT1 prefers acyl donors with saturated and monounsaturated FAs. Furthermore, the combination of substrates that resulted in the highest activity for DGAT2, but very low activity for DGAT1, corresponds to TAG species previously shown to increase inC. sativaseeds with downregulated DGAT1. Similarly, the combinations of substrates that gave the highest PDAT1 activity were also those that produce the two TAG species (54:7 and 54:8 TAG) with the highest increase in PDAT overexpressingC. sativaseeds. Thus, thein vitrodata correlate well with the changes in the overall fatty acid profile and TAG species inC. sativaseeds with altered DGAT1 and PDAT activity. Additionally,in vitrostudies ofC. sativaphosphatidycholine:diacylglycerol cholinephosphotransferase (PDCT), another activity involved in TAG biosynthesis, revealed that PDCT accepts substrates with different desaturation levels. Furthermore, PDCT was unable to use DAG with ricineoleyl groups, and the presence of this substrate also inhibited PDCT from using other DAG-moieties. This gives insights relating to previousin vivostudies regarding this enzyme.

Keywords

Camelina; Kennedy pathway; fatty acid composition; acyltransferase; diacylglycerol acyltransferase; diacylglycerol; triacylglycerol; phosphatidylcholine

Published in

Frontiers in Plant Science
2020, Volume: 11, article number: 1144
Publisher: FRONTIERS MEDIA SA

SLU Authors

• Lager, Ida

  • Department of Plant Breeding, Swedish University of Agricultural Sciences
    

• Stymne, Sten

  • Department of Plant Breeding, Swedish University of Agricultural Sciences
    

• Jeppsson, Simon

  • Department of Plant Breeding, Swedish University of Agricultural Sciences
    

• Marmon, Sofia

  • Department of Plant Breeding, Swedish University of Agricultural Sciences
    
  • University of Göttingen

UKÄ Subject classification

Plant Biotechnology
Biochemistry and Molecular Biology


Publication identifier

DOI: https://doi.org/10.3389/fpls.2020.01144

Permanent link to this page (URI)

https://res.slu.se/id/publ/107908