Indole-3-acetic acid (IAA) biosynthesis in the smut fungus Ustilago maydis and its relevance for increased IAA levels in infected tissue and host tumour formation.

ABSTRACT: Infection of maize (Zea mays) plants with the smut fungus Ustilago maydis is characterized by excessive host tumour formation. U. maydis is able to produce indole-3-acetic acid (IAA) efficiently from tryptophan. To assess a possible connection to the induction of host tumours, we investigated the pathways leading to fungal IAA biosynthesis. Besides the previously identified iad1 gene, we identified a second indole-3-acetaldehyde dehydrogenase gene, iad2. Deltaiad1Deltaiad2 mutants were blocked in the conversion of both indole-3-acetaldehyde and tryptamine to IAA, although the reduction in IAA formation from tryptophan was not significantly different from Deltaiad1 mutants. To assess an influence of indole-3-pyruvic acid on IAA formation, we deleted the aromatic amino acid aminotransferase

SUBMITTER: Reineke G 

PROVIDER: S-EPMC6640242 | biostudies-literature | 2008 May

REPOSITORIES: biostudies-literature