Seeds of members of the genus <
i>
Cuphea<
/i>
accumulate medium-chain fatty acids (MCFAs
8:0?14:0). MCFA- and palmitic acid- (16:0) rich vegetable oils have received attention for jet fuel production, given their similarity in chain length to Jet A fuel hydrocarbons. Studies were conducted to test genes, including those from <
i>
Cuphea<
/i>
, for their ability to confer jet fuel-type fatty acid accumulation in seed oil of the emerging biofuel crop <
i>
Camelina sativa<
/i>
. Transcriptomes from <
i>
Cuphea viscosissima<
/i>
and <
i>
Cuphea pulcherrima<
/i>
developing seeds that accumulate >
90% of C8 and C10 fatty acids revealed three <
i>
FatB<
/i>
cDNAs (<
i>
CpuFatB3<
/i>
, <
i>
CvFatB1<
/i>
, and <
i>
CpuFatB4<
/i>
) expressed predominantly in seeds and structurally divergent from typical FatB thioesterases that release 16:0 from acyl carrier protein (ACP). Expression of <
i>
CpuFatB3<
/i>
and <
i>
CvFatB1<
/i>
resulted in <
i>
Camelina<
/i>
oil with capric acid (10:0), and <
i>
CpuFatB4<
/i>
expression conferred myristic acid (14:0) production and increased 16:0. Co-expression of combinations of previously characterized <
i>
Cuphea<
/i>
and California bay FatBs produced <
i>
Camelina<
/i>
oils with mixtures of C8?C16 fatty acids, but amounts of each fatty acid were less than obtained by expression of individual <
i>
FatB<
/i>
cDNAs. Increases in lauric acid (12:0) and 14:0, but not 10:0, in <
i>
Camelina<
/i>
oil and at the <
i>
sn-2<
/i>
position of triacylglycerols resulted from inclusion of a coconut lysophosphatidic acid acyltransferase specialized for MCFAs. RNA interference (RNAi) suppression of <
i>
Camelina<
/i>
?-ketoacyl-ACP synthase II, however, reduced 12:0 in seeds expressing a 12:0-ACP-specific FatB. Here, <
i>
Camelina<
/i>
lines presented here provide platforms for additional metabolic engineering targeting fatty acid synthase and specialized acyltransferases for achieving oils with high levels of jet fuel-type fatty acids.