Identification of a fabZ gene essential for flexirubin synthesis in Cytophaga hutchinsonii.

Cytophaga hutchinsonii, an aerobic soil bacterium which could degrade cellulose, produces yellow flexirubin pigments. In this study, fabZ, annotated as a putative β-hydroxyacyl-(acyl carrier protein) (ACP) dehydratase gene, was identified by insertional mutation and gene deletion as an essential gene for flexirubin pigment synthesis. The availability of a FabZ mutant that fails to produce flexirubin allowed us to investigate the biological role of the pigment in C. hutchinsonii. Loss of flexirubin made the FabZ mutant more sensitive to UV radiation, oxidative stress and alkaline stress than the wild type.