Explaining, exploiting and controlling the staining of wood by UV tolerant fungi

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Explaining, exploiting and controlling the staining of wood by UV tolerant fungiWood is being replaced on a large scale for many outdoor uses because it is rapidly degraded by UV radiation and then colonized by dark-coloured staining fungi, which give the wood an unattractive blotchy-grey appearance. Restricting such fungal staining is becoming far more difficult because many of the fungicides that were able to control staining fungi are no longer available, and their replacements are less effective. Hence, new approaches to controlling the discolouration of wood by staining fungi are needed. One approach that is showing promise is to disrupt the synthesis of melanin by staining fungi. Staining fungi use melanin to protect themselves from the UV radiation that is incident at the surface of wood used outdoors. We have shown that very low concentrations (ppm) of agricultural chemicals that are used to control a fungal disease of rice can inhibit the synthesis of melanin by two staining fungi that colonise wood. Fungi targeted in this way in pure culture had reduced levels of melanin and failed to grow in the presence of the UV component of sunlight. This project will explore this promising approach further and construct robust systems suitable as wood treatments. We will also explore other novel approaches for controlling fungal staining of wood surfaces including: (a) Use of red or buff coloured strains of fungi as biocontrol agents and; (b) Use of titanium or zinc oxide nanoparticles (quantum dots) as photocatalytic control agents. Both these new approaches to controlling the staining of wood surfaces will be preceded by fundamental research that will probe in exquisite detail using state-of-the-art CFI instrumentation the effects of surface fungi and photo-catalytic nanoparticles on the micro-structure and physical and chemical properties of wood surfaces. Our research specifically targets wood, but it is also more broadly relevant to the control of biofilms that despoil other building materials. The scale of this problem is immense and can be gauged with reference to a recent estimate that the economic impact of microbial-induced corrosion of concrete in the USA alone exceeds $100 billion per annum.