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Updated: Aug 28, 2026

High-throughput Siderophore Screening from Environmental Samples: Plant Tissues, Bulk Soils, and Rhizosphere Soils
12:36

High-throughput Siderophore Screening from Environmental Samples: Plant Tissues, Bulk Soils, and Rhizosphere Soils

Published on: February 9, 2019

Outer membrane protein mediating iron uptake via pyoverdinpss, the fluorescent siderophore produced by Pseudomonas

Y S Cody, D C Gross

    Journal of Bacteriology
    |May 1, 1987
    PubMed

    Insights

    Pseudomonas syringae pv. syringae produces pyoverdine (a siderophore) for iron transport. Iron uptake via pyoverdine is not essential for this bacterium

    Area of Science:

    • Microbiology
    • Plant Pathology
    • Biochemistry

    Background:

    • Pseudomonas syringae pv. syringae B301D produces pyoverdine, a fluorescent siderophore, for high-affinity iron transport in iron-limited conditions.
    • Iron uptake is crucial for bacterial growth and virulence, often mediated by specific outer membrane proteins.

    Purpose of the Study:

    • To investigate the role of pyoverdine and iron uptake in the pathogenicity of Pseudomonas syringae pv. syringae.
    • To identify iron-regulated outer membrane proteins involved in iron transport.

    Main Methods:

    • Two-dimensional electrophoresis was used to compare outer membrane proteins between low and high iron conditions.
    • Mutants deficient in iron uptake (Iu-) or pyoverdine synthesis (Flu-) were created and analyzed.
    • Pathogenicity tests were conducted on immature sweet cherry fruit.

    Main Results:

    • Nine iron-regulated outer membrane proteins were identified, mostly with high molecular weights (74,000-80,000 Da).
    • The iron uptake mutant (Iu-) lacked a major 74,000 Da iron-regulated protein (protein 4a).
    • The nonfluorescent mutant (Flu-) showed no difference in outer membrane protein profiles compared to the wild-type.

    Conclusions:

    • Pyoverdine production and subsequent iron(III) uptake are not critical for the pathogenicity or virulence of Pseudomonas syringae pv. syringae on cherry fruit.
    • Specific outer membrane proteins are regulated by iron availability, suggesting a role in iron transport, but this process is not essential for virulence in this context.

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