Aureobasidium pullulans is the main organism causing disfigurement of coatings on wood and the surface of exposed timber. This disfigurement of timber in-service is referred to as “bluestain in-service”. A. pullulans is also associated with the sapstaining of dead wood in the forest and in-service. A. pullulans is noted for its highly variable growth forms (polymorphisms). This variability presents problems when identifying environmental isolates, due to the morphological similarity of other blue stain fungi, mainly Hormonema dematioides. Molecular analysis has proven to be both accurate and reliable in distinguishing between these two morphologically similar bluestain fungi. The method was devised as part of a bigger research project designed to look in detail at the polymorphisms and physiology of Aureobasidium-type fungi. The establishment of a working library of strains and isolates was aided by many members of the International Research Group on Wood Preservation. The devised method illustrated the existing problem of distinguishing between A. pullulans and H. dematioides. The protocol has been devised to simplify what can be a long complicated procedure. By sequencing direct from amplified PCR (Polymerase Chain Reaction) products, there is no need for cloning large DNA fragments into vectors, followed by sequencing. The extraction method offered here will give DNA of sufficient purity to allow for further genetic analysis if required. This method allows consistent differentiation between isolates of A. pullulans and H. dematioides. Aureobasidium pullulans is the main organism causing disfigurement of coatings on wood and the surface of exposed timber. This disfigurement of timber in-service is referred to as “bluestain in-service”. A. pullulans is also associated with the sapstaining of dead wood in the forest and in-service. A. pullulans is noted for its highly variable growth forms (polymorphisms). This variability presents problems when identifying environmental isolates, due to the morphological similarity of other blue stain fungi, mainly Hormonema dematioides. Molecular analysis has proven to be both accurate and reliable in distinguishing between these two morphologically similar bluestain fungi. The method was devised as part of a bigger research project designed to look in detail at the polymorphisms and physiology of Aureobasidium-type fungi. The establishment of a working library of strains and isolates was aided by many members of the International Research Group on Wood Preservation. The devised method illustrated the existing problem of distinguishing between A. pullulans and H. dematioides. The protocol has been devised to simplify what can be a long complicated procedure. By sequencing direct from amplified PCR (Polymerase Chain Reaction) products, there is no need for cloning large DNA fragments into vectors, followed by sequencing. The extraction method offered here will give DNA of sufficient purity to allow for further genetic analysis if required. This method allows consistent differentiation between isolates of A. pullulans and H. dematioides.

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