Genetic Regulation of Iron in Erwinia chrysanthemi as Pertains to Bacterial Virulence

Expert, Dominique

doi:10.1007/1-4020-4743-6_10

Cited by 6 publications

(9 citation statements)

References 30 publications

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“…The dynamics of iron availability during bacterial pathogenesis of plants is less well understood, although a number of studies have strongly correlated iron acquisition and virulence in planta [17], [18], [29]. During infection, Pectobacterium species release large quantities of pectinases and cellulases which macerate host tissues creating the distinctive soft rot associated with the genus.…”

Section: Discussionmentioning

confidence: 99%

Ferredoxin Containing Bacteriocins Suggest a Novel Mechanism of Iron Uptake in Pectobacterium spp

2012

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In order to kill competing strains of the same or closely related bacterial species, many bacteria produce potent narrow-spectrum protein antibiotics known as bacteriocins. Two sequenced strains of the phytopathogenic bacterium Pectobacterium carotovorum carry genes encoding putative bacteriocins which have seemingly evolved through a recombination event to encode proteins containing an N-terminal domain with extensive similarity to a [2Fe-2S] plant ferredoxin and a C-terminal colicin M-like catalytic domain. In this work, we show that these genes encode active bacteriocins, pectocin M1 and M2, which target strains of Pectobacterium carotovorum and Pectobacterium atrosepticum with increased potency under iron limiting conditions. The activity of pectocin M1 and M2 can be inhibited by the addition of spinach ferredoxin, indicating that the ferredoxin domain of these proteins acts as a receptor binding domain. This effect is not observed with the mammalian ferredoxin protein adrenodoxin, indicating that Pectobacterium spp. carries a specific receptor for plant ferredoxins and that these plant pathogens may acquire iron from the host through the uptake of ferredoxin. In further support of this hypothesis we show that the growth of strains of Pectobacterium carotovorum and atrosepticum that are not sensitive to the cytotoxic effects of pectocin M1 is enhanced in the presence of pectocin M1 and M2 under iron limiting conditions. A similar growth enhancement under iron limiting conditions is observed with spinach ferrodoxin, but not with adrenodoxin. Our data indicate that pectocin M1 and M2 have evolved to parasitise an existing iron uptake pathway by using a ferredoxin-containing receptor binding domain as a Trojan horse to gain entry into susceptible cells.

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Section: Discussionmentioning

confidence: 99%

Ferredoxin Containing Bacteriocins Suggest a Novel Mechanism of Iron Uptake in Pectobacterium spp

2012

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“…In particular, oxidative stress and iron starvation emerged as unfavourable conditions encountered by E. chrysanthemi at the onset of infection. Accordingly, mutants lacking either defence systems against oxidative stress or highly efficient iron‐acquiring systems exhibited reduced virulence (El Hassouni et al ., 1999; Santos et al ., 2001; Boccara et al ., 2005; Expert, 2005; Boughammoura et al ., 2007). Hence, investigating Fe/S biogenesis systems in the context of virulence became of interest as Fe/S biogenesis is a central process that can be difficult to perform in conditions of iron starvation and oxidative stress.…”

Section: Discussionmentioning

confidence: 99%

“…Iron starvation and oxidative stress, two environmental conditions, highly detrimental for Fe/S enzymes biogenesis and functioning, are met by most bacterial pathogens upon infection of their host. For instance, the plant pathogen E. chrysanthemi faces oxidative stress and iron starvation during infection, and accordingly oxidative stress‐resistant systems as well as iron‐metabolizing systems are required for virulence (El Hassouni et al ., 1999; Santos et al ., 2001; Boccara et al ., 2005; Expert, 2005; Boughammoura et al ., 2007). Furthermore, it was shown that in response to E. chrysanthemi infection, the susceptible host, Arabidopsis thaliana , produces reactive oxygen species (Fagard et al ., 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Cysteine desulphurases allow production of the sulphur moiety which eventually forms the Fe/S cluster. Cysteine desulphurases of each system are referred to as NifS, IscS, SufS (which acts with SufE) and CsdA (which acts with CsdE) (Mihara et al, 2000;Loiseau et al, 2003;2005;Kessler, 2006). Scaffolds bind iron and sulphur separately, allowing Fe/S to form and eventually transfer to apoproteins.…”

Section: Introductionmentioning

confidence: 99%

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Biogenesis of Fe/S proteins and pathogenicity: IscR plays a key role in allowing Erwinia chrysanthemi to adapt to hostile conditions

Rincón‐Enríquez

Crété

Barras

et al. 2008

Molecular Microbiology

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SummaryThe Erwinia chrysanthemi genome is predicted to encode three systems, Nif, Isc and Suf, known to assist Fe/S cluster biogenesis and the CsdAE cysteine desulphurase. Single iscU, hscA and fdx mutants were found sensitive to paraquat and exhibited reduced virulence on both chicory leaves and Arabidopsis thaliana. Depletion of the whole Isc system led to a pleiotropic phenotype, including sensitivity to both paraquat and 2,2Ј-dipyridyl, auxotrophies for branched-chain amino acids, thiamine, nicotinic acid, and drastic alteration in virulence. IscR was able to suppress all of the phenotypes listed above in a sufCdependent manner while depletion of the Isc system led to IscR-dependent activation of the suf operon. No virulence defects were found associated with csdA or nifS mutations. Surprisingly, we found that the sufC mutant was virulent against A. thaliana, whereas its virulence had been found altered in Saintpaulia. Collectively, these results lead us to propose that E. chrysanthemi possess the Fe/S biogenesis strategy suited to the physico-chemical conditions encountered in its host upon infection. In this view, the IscR regulator, which controls both Isc and Suf, is predicted to play a major role in the ability of E. chrysanthemi to colonize a wide array of different plants.

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“…Analysis of the role of iron in the pathogenicity of E. chrysanthemi on Saintpaulia plants has shown that during infection, this bacterium requires two high-affinity-iron uptake systems mediated by the siderophores, chrysobactin and achromobactin (for a review, see Expert 2005). Chrysobactin is a monocatecholate-type siderophore while achromobactin is a citrate derived compound that involves carboxylate or/and hydroxyl donor groups for iron binding.…”

Section: Importance Of Iron In Erwinia Chysanthemi Infectionmentioning

confidence: 99%

Ferritins, bacterial virulence and plant defence

Boughammoura¹,

Franza²,

Dellagi³

et al. 2007

Biometals

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The enterobacterial pathogen Erwinia chrysanthemi causes soft rot diseases on a wide range of plants, including the model plant Arabidopsis thaliana. This bacterium proliferates in the host by secreting a set of pectin degrading enzymes responsible for symptom development. In addition, survival of this bacterium in planta requires two high-affinity iron acquisition systems mediated by siderophores and protective systems against oxidative damages, suggesting the implication by both partners of accurate mechanisms controlling their iron homeostasis under conditions of infection. In this review, we address this question and we show that ferritins both from the pathogen and the host are subtly implicated in the control of this interplay.

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Genetic Regulation of Iron in Erwinia chrysanthemi as Pertains to Bacterial Virulence

Cited by 6 publications

References 30 publications

Ferredoxin Containing Bacteriocins Suggest a Novel Mechanism of Iron Uptake in Pectobacterium spp

Ferredoxin Containing Bacteriocins Suggest a Novel Mechanism of Iron Uptake in Pectobacterium spp

Biogenesis of Fe/S proteins and pathogenicity: IscR plays a key role in allowing Erwinia chrysanthemi to adapt to hostile conditions

Ferritins, bacterial virulence and plant defence

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