Two putative genes do not encode β-ketoacyl-acyl carrier protein reductases.

encodes three putative β-ketoacyl-acyl carrier protein (ACP) reductases (FabG). The gene is located within the operon that encodes most of the fatty acid synthesis genes, while the putative and genes are located elsewhere on the chromosome. The genes were tested for the ability to complement the growth of an (Ts) strain at the non-permissive temperature. Of the three genes, only FabG1 restored growth at high temperature. Moreover, deletion of the gene resulted in an auxotrophic strain that required oleic acid for growth, arguing that it encodes the only functional β-ketoacyl-ACP reductase. Growth of this strain in the absence of fatty acid was restored by plasmid-borne , but not by plasmids encoding either or . Although has a putative binding site for the FabT transcription factor at the 5' end of the coding region, expression of a transcriptional fusion with β-galactosidase was unaffected by deletion of or by fatty acid supplementation.