The critical role of iron in host-pathogen relationships has been elucidated in infectious diseases of mammals, where the importance of siderophores in microbial pathogenesis has been demonstrated. Our group has established the role of iron and its ligands in the virulence of the plant pathogenic bacteria Dickeya dadantii (Erwinia chrysanthemi) and Erwinia amylovora. The genomes of the two pectinolytic enterobacterial species Pectobacterium atrosepticum SCRI1043 and D. dadantii 3937 have been sequenced and annotated. This review focuses on the functions involved in iron acquisition in both species. Besides the production and utilization of siderophores, P. atrosepticum and D. datantii have the capacity to use other iron sources. Indeed, both species are able to use haem iron, whereas only P. atrosepticum can transport the ferric citrate complex and only D. dadantii can acquire ferrous iron. These different modes of iron capture indicate that these species have to cope with various environmental and ecological conditions during their pathogenic life cycle.

Further reading: Iron Uptake and Homeostasis in Microorganisms

Labels: Erwinia, Iron capture, Iron transport systems, Iron uptake in Erwinia, Iron uptake systems, Iron-homeostasis, Iron-metabolism, Iron-uptake

Shigella spp. and pathogenic E. coli are characterized by a variety and abundance of iron transport systems. Although members of this group of bacteria are closely related genetically, they differ widely in the iron transport systems they use. This may reflect the different niches occupied by different strains and the nature of the source of iron available in a specific environment. Only the ferrous iron transporter Feo is common to all the commensals and pathogens. All members of this group produce one or more siderophore, but no single siderophore is produced by all. Other iron transport systems include heme transporters and the ferrous iron transporters Sit and Efe. With the exception of the genes for enterobactin and the Feo system, the iron transport genes in the enterics are found within pathogenicity islands or on plasmids and their presence often increases pathogenicity or colonization of niches within the host.

Further reading: Iron Uptake and Homeostasis in Microorganisms

Labels: E. coli, Iron transport systems, Iron-homeostasis, Iron-metabolism, Iron-uptake, Shigella