Effects of UV Radiation on Melanization and Growth of Fungi Isolated from Weathered Wood Surfaces
V A Hernández, P D Evans
This research tests the hypothesis that fungi isolated from weathered wood will respond to elevated levels of UV radiation by increasing their melanin production. To test this hypothesis, we measured the melanin production and mycelial color of Aureobasidium pullulans and Cladosporium cladosporioides, before and after the fungi were grown under artificial UV, visible light and complete darkness. Two albino fungi: A. pullulans and Ophiostoma piliferum, and one pigmented O. piliferum fungus were used as controls. Our results show that A. pullulans has the ability to increase its production of melanin when exposed to UV radiation. This adaptive response may protect A. pullulans from the high levels of UV radiation found at wood surfaces exposed outdoors. C. cladosporioides was highly melanized, irrespective of exposure to different light sources. Our findings suggest that the discoloration of weathered wood surfaces may be influenced by the response of fungi colonizing wood surfaces to UV radiation. Further research is needed to test this hypothesis.