Molecular characterization of siderophore biosynthesis in s .

Iron is an essential nutrient for all organisms. For pathogenic fungi, iron is essential for the success of infection. Thus, these organisms have developed high affinity iron uptake mechanisms to deal with metal deprivation imposed by the host. Siderophore production is one of the mechanisms that fungal pathogens employ for iron acquisition. spp. present orthologous genes encoding the enzymes necessary for the biosynthesis of hydroxamates, and plasma membrane proteins related to the transport of these molecules. All these genes are induced in iron deprivation. In addition, it has been observed that spp. are able to use siderophores to scavenge iron. Here we observed that addition of the xenosiderophore ferrioxamine B FOB) to culture medium results in repression (at RNA and protein levels) of the SidA, the first enzyme of the siderophore biosynthesis pathway. Furthermore, SidA activity was reduced in the presence of FOB, suggesting that blocks siderophores biosynthesis and can explore siderophores in the environment to scavenge iron. In order to support the importance of siderophores on sp. life and infection cycle, silenced mutants for the gene were obtained by antisense RNA technology. The obtained strains displayed decreased siderophore biosynthesis in iron deprivation conditions and reduced virulence to an invertebrate model.