Agrobacterium-mediated transformation of the white-rot fungus Physisporinus vitreus.

The biotechnologically important white-rot fungus Physisporinus vitreus was co-cultivated with Agrobacterium tumefaciens AGL-1 carrying plasmids with nourseothricin resistance as the selectable marker gene and red fluorescence protein as a visual marker. Mitotically stable transformed isolates were obtained showing red fluorescence protein activity.

Modelling the effect of environmental factors on the hyphal growth of the basidiomycete Physisporinus vitreus.

The present work investigated the effects of environmental factors on the growth of fungal colonies of the white-rot basidiomycetes Physisporinus vitreus using a lattice-free discrete modeling approach called the fungal growth model (FGM), in which hyphae and nutrients are considered as discrete structures. A discrete modeling approach enables the underlying mechanistic rule concerning the basic architecture and dynamics of fungal networks to be studied on the scale of a single colony. By comparing simulations of the FGM with laboratory experiments of fungal colonies growing on malt extract agar we show that the combined effects of water activity, temperature and pH on the radial growth rate of fungal mycelia on the macroscopic scale may be explained by a power law for the costs of hyphal maintenance and expansion on the microscopic scale. Information about the response of the fungal mycelium at the micro- scopic level to environmental conditions is essential for simulating its behavior in complex structure substrates such as wood, where the effect of the fungus on the wood (i.e. the degradation of the cell wall) changes the local environmental condition (e.g. the permeability of the substrate and therefore the water activity in a colonized wood cell lumen). Using a combination of diffusion and moisture processes with the FGM may increase our understanding of the colonization strategy of P. vitreus and help to optimize its growth behavior for biotechnological applications such as bioincising.

Modelling the hyphal growth of the wood-decay fungus Physisporinus vitreus.

The white-rot fungus, Physisporinus vitreus, degrades the membranes of bordered pits in tracheids and consequently increases the permeability of wood, which is a process that can be used by the wood industry to improve the uptake of wood preservatives and environmentally benign wood modification substances to enhance the use and sustainability of native conifer wood species. To understand and apply this process requires an understanding of how a complex system (fungus-wood) interacts under defined conditions. We present a three-dimensional fungal growth model (FGM) of the hyphal growth of P. vitreus in the heartwood of Norway spruce. The model considers hyphae and nutrients as discrete structures and links the microscopic interactions between fungus and wood (e.g. degradation rate and degree of opening of pits) with macroscopic system properties, such penetration depth of the fungus, biomass, and distribution of destroyed pits in early- and latewood. Simulations were compared with experimental data. The growth of P. vitreus is characterized by a stepwise capture of the substrate and the effect of this on wood according to different model parameters is discussed.