Characterising the role of GABA and its metabolism in the wheat pathogen Stagonospora nodorum.

ABSTRACT: A reverse genetics approach was used to investigate the role of ?-aminobutyric acid metabolism in the wheat pathogenic fungus Stagonospora nodorum. The creation of mutants lacking Sdh1, the gene encoding succinic semialdehyde dehydrogenase, resulted in strains that grew poorly on ?-aminobutyric acid as a nitrogen source. The sdh1 mutants were more susceptible to reactive oxygen stress but were less affected by increased growth temperatures. Pathogenicity assays revealed that the metabolism of ?-aminobutyric acid is required for complete pathogenicity. Growth assays of the wild-type and mutant strains showed that the inclusion of ?-aminobutyric acid as a supplement in minimal media (i.e., not as a nitrogen or carbon source) resulted in restricted growth but increased sporulation. The addition of glutamate, the precursor to GABA, had no effect on either growth or sporulation. The ?-aminobutyric acid effect on sporulation was found to be dose dependent and not restricted to Stagonospora nodorum with a similar effect observed in the dothideomycete Botryosphaeria sp. The positive effect on sporulation was assayed using isomers of ?-aminobutyric acid and other metabolites known to influence asexual development in Stagonospora nodorum but no effect was observed. These data demonstrate that ?-aminobutyric acid plays an important role in Stagonospora nodorum in responding to environmental stresses while also having a positive effect on asexual development.

SUBMITTER: Mead O 

PROVIDER: S-EPMC3827059 | biostudies-other | 2013

REPOSITORIES: biostudies-other