Physiological implications of trehalose in the ectomycorrhizal fungus Pisolithus sp. under thermal stress

The trehalose cycle in filamentous fungi has been suggested to be an important mechanism of tolerance against adverse stress conditions, particularly in thermal stress. Here, we demonstrate that trehalose and trehalase activity can be involved as an additional mechanism in development of thermotolerance in Pisolithus sp. In response to heat shock at 42 °C, an accumulation of intracellular trehalose and an increase in trehalase activity in the mycelial mass of the fungus was observed, when compared to the control treatment (28 °C). In vitro, assays showed that trehalose had a protective effect on β-glucosidase activity under thermal stress. Therefore, trehalose production may be an important mechanism of protection in ectomycorrhizal fungi, and this capacity could be used in the selection of isolates with greater capacity for adaptation to environmental stress.