Desferrioxamine-dependent iron transport in Erwinia amylovora CFBP1430: cloning of the gene encoding the ferrioxamine receptor FoxR

Abstract

Iron deprivation of Erwinia amylovora CFBP1430, a species causing fire blight on Pomoïdeae, was shown to induce the production of siderophores of the desferrioxamine (dfo) family and two outer membrane polypeptides with apparent molecular weight of about 70 and 80 kDa, respectively. Cyclic dfo E was characterized as the major metabolite. Phage MudIIpR13 insertional mutagenesis and screening on CAS-agar medium yielded three dfo non-producing and one overproducing clones. These clones failed to grow in the presence of the Fe(III) chelator EDDHA and were determined further as dfo and ferrioxamine transport negative mutants, respectively. The transport mutant which appeared to lack the 70 kDa polypeptide in the outer membrane allowed the purification of dfo E. Growth under iron limitation of dfo negative mutants was stimulated with ferrioxamine E and B but not with other ferrisiderophores tested. The host DNA sequence flanking the left terminal part of the MudIIpR13 prophage responsible for the transport mutation was cloned and used to probe a parental gene library by DNA-DNA hybridization. Two recombinant cosmids restoring the transport mutation to normal were identified. Both cosmids also conferred the ability to utilize ferrioxamine B and E as iron sources on a FhuE- mutant of Escherichia coli. This correlated with the production of an additional polypeptide of 70 kDa in the outer membrane of E. coli transconjugants, thus confirming that this protein serves the ferrioxamine receptor function (FoxR) in E. amylovora.

Multiple biosynthetic and uptake systems mediate siderophore-dependent iron acquisition in Streptomyces coelicolor A3(2) and Streptomyces ambofaciens ATCC 23877

“…They also suggest that in these pathogenic strains only one siderophore is important during certain stages of infection (Cendrowski et al, 2004;Franza et al, 2005). Desferrioxamine production seems to be conserved among Streptomyces spp., yet several soil-dwelling non-actinomycetes can utilize the ferric complexes of these hydroxamate metabolites (Meyer & Abdallah, 1980;Berner et al, 1988;Kachadourian et al, 1996). It is tempting to speculate that uptake and utilization of ferrioxamines as xenosiderophores by microbial competitors in the environment of S. coelicolor and S. ambofaciens have driven acquisition of the cch cluster by these organisms as a 'contingency plan' to overcome such biological competition for iron (Challis & Hopwood, 2003).…”

Genomics and current genetic understanding of Erwinia amylovora and the fire blight antagonist Pantoea vagans

“…Erwinia spp. produce the hydroxamate siderophore desferrioxamine E (Feistner et al 1993;Kachadourian et al 1996) and the specific TonB-dependent ferrioxamine receptor FoxR, both involved in iron uptake. Mutation of these genes leads to colonization defects of E. amylovora on flowers (Dellagi et al 1998), whereas DFO E might be protective to oxidative conditions (Venisse et al 2003).…”

Microbial Siderophores

“…The crystals of the Fe 3+ Lig complexes of ferrioxamine D 1 and E are racemic mixtures of L-cis and D-cis coordination isomers (154, 366a). The outer membrane receptor protein of Erwinia amylovora was structurally determined (180). Siderophore activity was demonstrated for 55 Fe-labeled ferrioxamine E (30a).…”