| Summary: | Lignin degrading (white-rot) basidiomycete fungi are major agents of carbon cycling and play a key role in maintaining forest ecosystems. Trametes versicolor is a white- rot fungus of both industrial and ecological interest. The aims of this study were to investigate the effects of biotic and abiotic stress factors on growth, ligninolytic enzyme (laccase) production and gene expression in white-rot fungi, using T. versicolor as a model for most of the work. Mycelial interactions are important in defining community structure in wood-rotting fungi, and during these interactions volatile organic compounds (VOCs) are produced which can affect the growth of other fungi, at a distance. The effects of different combinations of interacting fungi on T. versicolor growth and ligninolytic enzyme production showed that effects were variable. Effects of VOCs from interaction on wood blocks were more significant than those on agar. Abiotic stress factors affect fungal metabolism and thereby regulate their biological activity. This study investigated the effect of abiotic stress factors on T. versicolor using different temperatures (low and high), osmotic pressure (KCl) and nutrients (no and low nitrogen). Growth rate, laccase production and expression of three genes (FRA19, Nox, and Lacc) were mainly reduced when the abiotic stress was imposed, although there was some variability in gene expression. Laccase is encoded by a gene family and differential expression of gene family members under stress treatments was investigated. Some evidence for an over-representation of γ group sequences following stress treatments was found. Future directions are discussed to further investigate the roles of biotic and abiotic stress in regulating the growth and underlying biological processes of white rot fungi.
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