1. Thioquinolobactin, a Pseudomonas siderophore with antifungal and anti- Pythium activity.
- Author
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Matthijs, Sandra, Tehrani, Kourosch Abbaspour, Laus, George, Jackson, Robert W., Cooper, Richard M., and Cornelis, Pierre
- Subjects
PYTHIUM ,ANTI-infective agents ,PSEUDOMONAS fluorescens ,BIOSYNTHESIS ,HYDROLYSIS ,ANTIFUNGAL agents - Abstract
Under conditions of iron limitation Pseudomonas fluorescens ATCC 17400 produces two siderophores, pyoverdine, and a second siderophore quinolobactin, which itself results from the hydrolysis of the unstable molecule 8-hydroxy-4-methoxy-2-quinoline thiocarboxylic acid (thioquinolobactin). Pseudomonas fluorescens ATCC 17400 also displays a strong in vitro antagonism against the Oomycete Pythium, which is repressed by iron, suggesting the involvement of a siderophore(s). While a pyoverdine-negative mutant retains most of its antagonism, a thioquinolobactin-negative mutant only slowed-down Pythium growth, and a double pyoverdine-, thioquinolobactin-negative mutant, which does not produce any siderophore, totally lost its antagonism against Pythium. The siderophore thioquinolobactin could be purified and identified from spent medium and showed anti- Pythium activity, but it was quickly hydrolysed to quinolobactin, which we showed has no antimicrobial activity. Analysis of antagonism-affected transposon mutants revealed that genes involved in haem biosynthesis and sulfur assimilation are important for the production of thioquinolobactin and the expression of antagonism. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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