Involved in the biosynthesis of lipid A, a phosphorylated glycolipid that in bacteria anchors the lipopolysaccharide to the outer membrane of the cell. Lipid A-like molecules in plants may serve as structural components of the outer membranes of mitochondria and/or chloroplasts, or may be involved in signal transduction or plant defense responses. a (3R)-hydroxyacyl-[ACP] + a UDP-3-O-[(3R)-3-hydroxyacyl]-alpha-D-glucosamine = a UDP-2-N,3-O-bis[(3R)-3-hydroxyacyl]-alpha-D-glucosamine + H(+) + holo-[ACP] Glycolipid biosynthesis; lipid IV(A) biosynthesis; lipid IV(A) from (3R)-3-hydroxytetradecanoyl-[acyl-carrier-protein] and UDP-N-acetyl-alpha-D-glucosamine: step 3/6. Homotrimer. No visible phenotype under normal growth conditions, but plants lacking LPXD1 accumulate very low levels of 2,3-diacylglucosamine-1-phosphate. Belongs to the transferase hexapeptide repeat family. LpxD subfamily.