Microscopic Investigation on Fungal Pigment Formation and its Morphology in Wood Substrates

Melanin formation and assembly by fungi has largely been investigated mainly for its importance in pathogenesis, as well as to establish the functions and biosynthetic pathways of melanin formed during the process of successional wood decay. It is known that melanin formation varies based on fungal species, especially melanin produced by ascomycetes versus basidiomycetes, and that the mechanisms of melanin production by basidiomycetes are more complex and thus far not entirely elucidated. This study compares in vivo melanin formation by Oxyporus populinus in sugar maple and Fomes fomentarius in birch, and in vitro pigmentation by Trametes versicolor, Xylaria polymorpha and Inonotus hispidus in sugar maple and beech, with and without the influence of the melanin precursor, catechol. The results of this research indicate a bior multi-modal activity of melanin production and assembly by wood decay fungi, and identify possible variations in melanin formation mechanisms as influenced by fungal and wood species.