Quinone reductase activity is widespread in lichens

In our earlier work, we demonstrated that the oxidases tyrosinase (TYR), laccase (LAC), and a heme peroxidase (POX) occur widely in lichens. Here we report on the occurrence of another oxidoreductase enzyme, quinone reductase (QR) (EC 1.6.5.5). While QR has been reported to occur widely in other organisms, there is currently no information on QR activities in lichens. Here we present a survey of QR activity in 14 species of lichens. Results demonstrate that QR activity is readily detectable in all lichen species tested. However, activities vary greatly, with 'jelly' lichens in the genera Collema and Leptogium having the highest activities. QR, LAC and POX are all believed to have a role in extracellular hydroxyl radical production. However, in this study no correlation was found between the activities of these enzymes and the rates at which hydroxyl radicals were produced. Possible roles for QR in lichen biology are discussed.

Automated summary

The occurrence of oxidoreductase enzymes such as tyrosinase, laccase, heme peroxidase, and quinone reductase in lichens was demonstrated, with the latter showing varying activities among different lichen species. Despite the belief that these enzymes play a role in extracellular hydroxyl radical production, this study did not find a correlation between enzyme activities and hydroxyl radical production rates. Possible roles for quinone reductase in lichen biology were discussed.