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Arne Schwelm

Doctor of Philosophy, (Molecular Microbiology)
Study Completed: 2008
College of Sciences


Thesis Title
Investigations of dothistromin gene expression in Dothistroma septosporum and the putative role of dothistromin toxin

Read article at Massey Research Online: MRO icon

Mr Schwelm studied the plant-pathogen system of the fungus Dothistroma septosporum and pine. The study focused on genes required for synthesis of the mycotoxin dothistromin, produced by the fungus, which was thought to be a major factor in pine needle blight disease. Investigations of dothistromin gene expression in culture revealed an unusual pattern. The dothistromin genes were expressed early at the exponential stage of growth, in contrast to other secondary metabolites, which are usually produced at a late stage. Dothistromin-deficient mutants containing a green fluorescence reporter gene, produced by Mr Schwelm, were used in further studies which dismissed dothistromin as a pathogenicity factor. The potential of dothistromin in competition was investigated. While dothistromin, as having an essential role in pine needle blight disease, was ruled out, the thesis provides new hypotheses about the role of dothistromin in competition between D. septosporum and other microorganisms in the forest environment.

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