Functional identification of the gene encoding enoyl-CoA hydratase for siderophore biosynthesis in the entomopathogen Beauveria bassiana.

The entomopathogenic fungus Beauveria bassiana possesses a siderophore biosynthetic pathway that closely resembles the general pathway found in filamentous fungi. Although a peroxisomal enoyl-CoA hydratase (Ech), SidH, has been implicated in the siderophore biosynthesis, its ortholog in B. bassiana appears to be functionally dispensable for siderophore production. In this study, gene function analysis was used to characterize the functional Ech involved in siderophore production among other fourteen ECH-domain proteins. The results indicated these proteins performed different roles in fungal development into conidia and blastospores. BbEch1, a cytoplasmic enoyl-CoA hydratase, has important roles in vegetative growth, stress resistance, and virulence in B. bassiana. Particularly, BbEch1 is involved in the siderophore biosynthesis which is critical for iron acquisition during fungal development. This research identifies a cytoplasmic enoyl-CoA hydratase different from that in general pathway, which implies a novel biosynthetic route for siderophores in filamentous fungi.