Format

Send to

Choose Destination
J Appl Microbiol. 2011 Oct;111(4):932-8. doi: 10.1111/j.1365-2672.2011.05109.x. Epub 2011 Aug 11.

Azotobacter vinelandii gene clusters for two types of peptidic and catechol siderophores produced in response to molybdenum.

Author information

1
Laboratory of Basic and Applied Molecular Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.

Abstract

AIM:

To characterize the complementary production of two types of siderophores in Azotobacter vinelandii.

METHODS AND RESULTS:

In an iron-insufficient environment, nitrogen-fixing A. vinelandii produces peptidic (azotobactin) and catechol siderophores for iron uptake to be used as a nitrogenase cofactor. Molybdenum, another nitrogenase cofactor, was also found to affect the production level of siderophores. Wild-type cells excreted azotobactin into molybdenum-supplemented and iron-insufficient medium, although catechol siderophores predominate in molybdenum-free environments. Two gene clusters were identified to be involved in the production of azotobactin and catechol siderophores through gene annotation and disruption. Azotobactin-deficient mutant cells produced catechol siderophores under the molybdenum-supplemented and iron-insufficient conditions, whereas catechol siderophore-deficient mutant cells extracellularly secreted excess azotobactin under iron-deficient condition independent of the concentration of molybdenum. This evidence suggests that a complementary siderophore production system exists in A. vinelandii.

CONCLUSIONS:

Molybdenum was found to regulate the production level of two types of siderophores. Azotobacter vinelandii cells are equipped with a complementary production system for nitrogen fixation in response to a limited quantity of metals.

SIGNIFICANCE AND IMPACT OF THE STUDY:

This is the first study identifying A. vinelandii gene clusters for the biosynthesis of two types of siderophores and clarifying the relationship between them.

[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Wiley
Loading ...
Support Center