Acyltransferases and methods of using

1. A method of producing triacylglycerols (TAGs) comprising medium-chain fatty acids (MCFAs) in an organism, said method comprising:

introducing a first transgene into the organism, wherein the first transgene comprises at least one nucleic acid sequence encoding a lysophosphatidic acid acyltransferase (LPAT) that exhibits a substrate specificity for saturated fatty acids, wherein the nucleic acid sequence encoding the LPAT has at least 95% sequence identity to SEQ ID NO: 1 or SEQ ID NO: 3; and

introducing a second transgene into the organism, wherein the second transgene comprises at least one nucleic acid sequence encoding a diacylglycerol acyltransferase (DGAT) that exhibits a substrate specificity for saturated fatty acids, wherein the nucleic acid sequence encoding the DGAT has at least 95% sequence identity to SEQ ID NO: 7 or SEQ ID NO: 9,

thereby producing TAGs comprising MCFAs in the organism, wherein the organism is a plant or a microbe.

2. The method of claim 1 , wherein at least 20% of the TAGs comprising MCFAs have a C8:0 or a C10:0 at sn-2 position.

3. The method of claim 1 , wherein the saturated fatty acids are selected from the group consisting of C8:0 and C10:0.

4. The method of claim 1 , wherein the nucleic acid sequence encoding the LPAT is a sequence having at least 95% sequence identity to SEQ ID NO:1.

5. The method of claim 1 wherein the nucleic acid sequence encoding the DGAT is a sequence having at least 95% sequence identity to SEQ ID NO:7.

6. The method of claim 1 , wherein the organism further comprises a nucleic acid sequence encoding a medium-chain fatty acid (MCFA)-specific thioesterase FatB.

7. The method of claim 6 , wherein the nucleic acid sequence encoding the MCFA-specific thioesterase FatB is selected from the group consisting of a nucleic acid sequence having at least 95% sequence identity to SEQ ID NO:11, a nucleic acid sequence having at least 95% sequence identity to SEQ ID NO:13, and a nucleic acid sequence having at least 95% sequence identity to SEQ ID NO:15.

8. The method of claim 1 , wherein the organism is a plant, and wherein the plant is Camelina sativa.

9. The method of claim 1 , wherein the first transgene and the second transgene each comprises a promoter.

10. The method of claim 9 , wherein the organism is a plant, and wherein each promoter is a seed-specific promoter.

11. The method of claim 1 , wherein the at least one nucleic acid sequence encoding a LPAT is operably linked to a seed-specific promoter, and wherein the at least one nucleic acid sequence encoding a DGAT is operably linked to a seed-specific promoter.

12. The method of claim 11 , wherein the medium-chain fatty acids are produced in the seed.

13. The method of claim 1 , wherein the introducing step is performed using Agrobacterium transformation, particle bombardment, or electroporation of protoplasts.

14. A method of producing triacylglycerols (TAGs) comprising medium-chain fatty acids (MCFAs), comprising:

providing an organism comprising a first and a second transgene, wherein the organism is a plant or a microbe,

wherein the first transgene comprises at least one nucleic acid sequence encoding a lysophosphatidic acid acyltransferase (LPAT) that exhibits a substrate specificity for saturated fatty acids, wherein the nucleic acid sequence encoding the LPAT has at least 95% sequence identity to SEQ ID NO:1 or SEQ ID NO:3,

wherein the second transgene comprises at least one nucleic acid sequence encoding a diacylglycerol acyltransferase (DGAT) that exhibits a substrate specificity for saturated fatty acids, wherein the nucleic acid sequence encoding the DGAT has at least 95% sequence identity to SEQ ID NO:7 or SEQ ID NO:9;

growing the organism under appropriate conditions; and

obtaining TAGs comprising MCFAs from the organism.

15. The method of claim 14 , wherein the TAGs are used in biofuel, jet fuel, detergents, and chemical feedstocks.