Transcriptome analysis of differential gene expression inDichomitus squalensduring interspecific mycelial interactions and the potential link with laccase induction

ABSTRACTInterspecific mycelial interactions between white rot fungi are always accompanied by increased production of laccase. In this study, the potential of white rot fungiDichomitus squalensfor enhancing laccase production during interaction with two other white rot fungiTrametes versicolororPleurotus ostreatuswas identified. To probe the mechanism of laccase induction and the role of laccase played during the combative interaction, we analyzed the laccase induction response to stressful conditions during fungal interaction related to the differential gene expression profile. We further confirmed the expression patterns of 16 selected genes by qRT-PCR analysis. We noted that many differential expression genes (DEGs) encoding proteins were involved in xenobiotics detoxification and ROS generation or reduction, including aldo/keto reductase, glutathione S-transferases, cytochrome P450 enzymes, alcohol oxidases and dehydrogenase, manganese peroxidase and laccase. Furthermore, many DEG-encoding proteins were involved in antagonistic mechanisms of nutrient acquisition and antifungal properties, including glycoside hydrolase, glucanase, chitinase and terpenoid synthases. DEGs analysis effectively revealed that laccase induction was likely caused by protective responses to oxidative stress and nutrient competition during fungal interspecific interaction.

Effect of fungal competition on decay rates in bicultured soil bottle assays

For decades, wood scientists and preservative formulators have employed the monocultured soil bottle assay to test efficacy of wood treatment in the laboratory as a rapid predictor of field performance. This study examines the effects of bicultured soil bottle assays on the decay by common wood decay fungi. Mycelial interactions were noted in early stages of colonization. With only two exceptions, a single fungus was apparent in each soil bottle, indicating dominance. The dominant fungi were not always the most efficient wood rots, and the rot type, white or brown, did not affect the dominance outcome on the preferred wood type.