Iron Deficiency Induced by Chrysobactin in Saintpaulia Leaves Inoculated with Erwinia chrysanthemi

Neema, Claire; Laulhère, Jean-Pierre; Expert, Dominique

doi:10.1104/pp.102.3.967

Cited by 56 publications

(33 citation statements)

References 19 publications

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“…Similarly, mutants affected in the achromobactin synthetic genes acsA or acsC cause only localized symptoms (147). Chrysobactin was also detected in plant tissues infected by E. chrysanthemi (354), and a fct-lacZ fusion was strongly expressed in planta during infection (310). These data show that siderophores are important for Erwinia pathogenicity and that iron availability thus plays a major role in regulation of E. chrysanthemi virulence.…”

Section: Induction Of Pectinolytic Enzymes By Iron Limitationmentioning

confidence: 72%

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

Brencic

Winans

2005

Microbiol Mol Biol Rev

337

208

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Diverse interactions between hosts and microbes are initiated by the detection of host-released chemical signals. Detection of these signals leads to altered patterns of gene expression that culminate in specific and adaptive changes in bacterial physiology that are required for these associations. This concept was first demonstrated for the members of the family Rhizobiaceae and was later found to apply to many other plant-associated bacteria as well as to microbes that colonize human and animal hosts. The family Rhizobiaceae includes various genera of rhizobia as well as species of Agrobacterium. Rhizobia are symbionts of legumes, which fix nitrogen within root nodules, while Agrobacterium tumefaciens is a pathogen that causes crown gall tumors on a wide variety of plants. The plant-released signals that are recognized by these bacteria are low-molecular-weight, diffusible molecules and are detected by the bacteria through specific receptor proteins. Similar phenomena are observed with other plant pathogens, including Pseudomonas syringae, Ralstonia solanacearum, and Erwinia spp., although here the signals and signal receptors are not as well defined. In some cases, nutritional conditions such as iron limitation or the lack of nitrogen sources seem to provide a significant cue. While much has been learned about the process of host detection over the past 20 years, our knowledge is far from being complete. The complex nature of the plant-microbe interactions makes it extremely challenging to gain a comprehensive picture of host detection in natural environments, and thus many signals and signal recognition systems remain to be described

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Section: Induction Of Pectinolytic Enzymes By Iron Limitationmentioning

confidence: 72%

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

Brencic

Winans

2005

Microbiol Mol Biol Rev

337

208

View full text Add to dashboard Cite

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“…Chrysobactin is one of two ferric ion chelators that allow the pathogen to compete with plant cells in iron sequestration (Neema et al, 1993;Dellagi et al, 2005;Dellagi et al, 2009). Arabidopsis treatment with chrysobactin promotes bacterial growth while also activating host SA-regulated responses and expression of FER1 encoding the iron storage protein ferritin (Dellagi et al, 2005;Dellagi et al, 2009).…”

Section: Modifi Cation Of Host Physiologymentioning

confidence: 99%

Necrotroph Attacks on Plants: Wanton Destruction or Covert Extortion?

Laluk

Mengiste

2010

The Arabidopsis Book

204

168

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Necrotrophic pathogens cause major pre-and post-harvest diseases in numerous agronomic and horticultural crops infl icting signifi cant economic losses. In contrast to biotrophs, obligate plant parasites that infect and feed on living cells, necrotrophs promote the destruction of host cells to feed on their contents. This difference underpins the divergent pathogenesis strategies and plant immune responses to biotrophic and necrotrophic infections. This chapter focuses on Arabidopsis immunity to necrotrophic pathogens. The strategies of infection, virulence and suppression of host defenses recruited by necrotrophs and the variation in host resistance mechanisms are highlighted. The multiplicity of intraspecifi c virulence factors and species diversity in necrotrophic organisms corresponds to variations in host resistance strategies. Resistance to host-specifi c necrotophs is monogenic whereas defense against broad host necrotrophs is complex, requiring the involvement of many genes and pathways for full resistance. Mechanisms and components of immunity such as the role of plant hormones, secondary metabolites, and pathogenesis-related proteins are presented. We will discuss the current state of knowledge of Arabidopsis immune responses to necrotrophic pathogens, the interactions of these responses with other defense pathways, and contemplate on the directions of future research.: e0136. of 34The Arabidopsis Book Infection by fungal necrotrophs generally involves stages of conidial attachment, germination, host penetration, primary lesion formation, lesion expansion, and tissue maceration followed by sporulation (Prins et al., 2000). Following germination, penetration may be achieved by active mechanisms such as appressoria formation and enzymatic degradation or passively through prior infection or wound sites as well as stomates (Prins et al., 2000). After entry, tissue is decomposed through further cellular dismantling using many of the lytic enzymes employed for initial penetration as well as toxic levels of reactive oxygen species (ROS). Many necrotrophs produce various low-molecular weight phytotoxic metabolites, ranging from host-specifi c to those having adverse effects on many diverse species (van Kan, 2006). Others secrete phytotoxic proteins known to induce necrosis, with the vast majority of broad host necrotrophs producing multiples of both (Pemberton and Salmond, 2004;Gijzen and Nurnberger, 2006;Choquer et al., 2007). Throughout infection, these fungi also actively manipulate host cellular machinery in order to suppress defenses and/or aid in disease progression. Some necrotrophs infl uence host phytohormone levels or employ their own hormone biosynthesis thereby disrupting defense signaling (Prins et al., 2000;Sharon et al., 2004). Others have adapted mechanisms to detoxify host metabolites that interfere with virulence (Morrissey and Osbourn, 1999).Overall, bacterial necrotrophs follow a similar mode of pathogenesis to their fungal counterparts, secreting virulence factors into host tissue to induc...

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“…CB and achromobactin production are required for the systemic progression of maceration symptoms on the hosts (Enard et al, 1988;Dellagi et al, 2005;Franza et al, 2005). Neema et al (1993) showed that the production of CB enables bacterial cells to compete with plant cells for iron, preventing sequestration of this metal by the plant ferritins. Consistently, the low availability of iron in the apoplasm of infected Saintpaulia leaves induces the expression of the fct gene, encoding the bacterial outer membrane ferric-chrysobactin (Fe-CB) transporter, which is up-regulated under iron depletion (Masclaux and Expert, 1995).…”

mentioning

confidence: 99%

Microbial Siderophores Exert a Subtle Role in Arabidopsis during Infection by Manipulating the Immune Response and the Iron Status

et al. 2009

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Siderophores (ferric ion chelators) are secreted by organisms in response to iron deficiency. The pathogenic enterobacterium Erwinia chrysanthemi produces two siderophores, achromobactin and chrysobactin (CB), which are required for systemic dissemination in host plants. Previous studies have shown that CB is produced in planta and can trigger the up-regulation of the plant ferritin gene AtFER1. To further investigate the function of CB during pathogenesis, we analyzed its effect in Arabidopsis (Arabidopsis thaliana) plants following leaf infiltration. CB activates the salicylic acid (SA)-mediated signaling pathway, while the CB ferric complex is ineffective, suggesting that the elicitor activity of this siderophore is due to its ironbinding property. We confirmed this hypothesis by testing the effect of siderophores structurally unrelated to CB, including deferrioxamine. There was no activation of SA-dependent defense in plants grown under iron deficiency before CB treatment. Transcriptional analysis of the genes encoding the root ferrous ion transporter and ferric chelate reductase, and determination of the activity of this enzyme in response to CB or deferrioxamine, showed that these compounds induce a leaf-to-root iron deficiency signal. This root response as well as ferritin gene up-regulation in the leaf were not compromised in a SA-deficient mutant line. Using the Arabidopsis-E. chrysanthemi pathosystem, we have shown that CB promotes bacterial growth in planta and can modulate plant defenses through an antagonistic mechanism between SA and jasmonic acid signaling cascades. Collectively, these data reveal a new link between two processes mediated by SA and iron in response to microbial siderophores.

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Iron Deficiency Induced by Chrysobactin in Saintpaulia Leaves Inoculated with Erwinia chrysanthemi

Cited by 56 publications

References 19 publications

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

Detection of and Response to Signals Involved in Host-Microbe Interactions by Plant-Associated Bacteria

Necrotroph Attacks on Plants: Wanton Destruction or Covert Extortion?

Microbial Siderophores Exert a Subtle Role in Arabidopsis during Infection by Manipulating the Immune Response and the Iron Status

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