Molecular and General Genetics MGG

, Volume 264, Issue 4, pp 521–530

Physiological evidence for differently regulated tryptophan-dependent pathways for indole-3-acetic acid synthesis in Azospirillum brasilense

Original paper

DOI: 10.1007/s004380000340

Cite this article as:
, , et al. Mol Gen Genet (2000) 264: 521. doi:10.1007/s004380000340

Abstract.

Disruption of ipdC, a gene involved in indole-3-acetic acid (IAA) production by the indole pyruvate pathway in Azospirillum brasilense Sp7, resulted in a mutant strain that was not impaired in IAA production with lactate or pyruvate as the carbon source. A tryptophan auxotroph that is unable to convert indole to tryptophan produced IAA if tryptophan was present but did not synthesise IAA from indole. Similar results were obtained for a mutant strain with additional mutations in the genes ipdC and trpD. This suggests the existence of an alternative Trp-dependent route for IAA synthesis. On gluconate as a carbon source, IAA production by the ipdC mutant was inhibited, suggesting that the alternative route is regulated by catabolite repression. Using permeabilised cells we observed the enzymatic conversion of tryptamine and indole-3-acetonitrile to IAA, both in the wild-type and in the ipdC mutant. IAA production from tryptamine was strongly decreased when gluconate was the carbon source.

Azospirillum brasilense Indole-3-acetic acid synthesis ipdC gene Tryptamine Indole-3-acetonitrile 

Copyright information

© Springer-Verlag 2000

Authors and Affiliations

  •  
    • 1
  •  
    • 2
  •  
    • 1
  •  
    • 2
  1. 1.Unité de Physiologie Cellulaire, CNRS URA D2172, Département des Biotechnologies, Institut Pasteur, 25–28, Rue du Dr. Roux, 75724 Paris Cedex, France
  2. 2.Centro de Investigaciones Microbiológicas, Universidad Autónoma de Puebla, Apdo. Postal 1622, C. P. 72000, Puebla, Pue. México

Personalised recommendations