Catalyzes the first step in the biosynthesis of ornithine lipids, which are phosphorus-free membrane lipids. Catalyzes the 3-hydroxyacyl-acyl carrier protein-dependent acylation of ornithine to form lyso-ornithine lipid (LOL). a (3R)-hydroxyacyl-[ACP] + L-ornithine = a lyso-ornithine lipid + H(+) + holo-[ACP] Lipid metabolism. Disruption mutant is unable to synthesize ornithine lipids. It can still induce nitrogen-fixing nodules on plants, but it shows delayed nodulation if compared to the wild type. Belongs to the acetyltransferase family. OlsB subfamily.