Epsilon Archive for Student Projects

Abstract

Genotypes of Camelina sativa have been developed to produce precursors of insect pheromones in
their seed oil that can be extracted and processed into pheromone compounds. Medium chain fatty
acids (MCFAs) are desired precursors to produce important C10-C14 pheromone compounds. Two
Lindera species are known to contain the desired FAs in their seed oil: Lindera obtusiloba and
Lindera benzoin. Acyl-CoA:diacylglycerol acyltransferase (DGAT) catalyzes the last step of
synthesis of triacylglycerol (TAG), and thus has an effect on fatty acid composition of TAG. We
have therefore studied DGAT1 and DGAT2 from both Lindera species by transient expression in
Nicotiana benthamiana leaves and measured substrate specificity with overexpressed plant genes in
yeast by using different acyl donor (acyl-CoAs) and acyl acceptors (diacylglycerol, DAG). Our
results from N. benthamiana infiltrations show that DGAT1 from L. obtusiloba and DGAT2 from
both Lindera species are capable of producing TAG with MCFAs like 12:0 and 14:0 FAs but not
10:0 or 12:1∆4
. Results from enzyme assays show that all DGATs were able to incorporate all
provided acyl-CoAs (10:0, 12:0, 12:1∆4
, 14:0, and 18:1-CoA) but had a higher specificity toward
12:0 and 14:0-CoA than 10:0 and 12:1∆4
-CoA. The reason that 10:0 and 12:1∆4 cannot be detected
in the N. benthamiana infiltrations could be due to lack of these substrates. Furthermore, all DGATs
showed a higher specificity toward 12:0-DAG than 18:1-DAG as acyl acceptor.