Mycoparasitism of Fomitopsis pinicola (Sw.) P. Karst. by Antrodiella citrinella Niemelä & Ryvarden

Abstract

Antrodiella species (Agaricomycotina, Polyporales) are often growing on or near to the living, dead, or dying fruitbodies of pioneer wood-inhabiting fungi. Antrodiella citrinella always occurs on wood that previously has been decayed by the polypore Fomitopsis pinicola. However, the underlying mechanism remained unclear. Based on field observations, it has been assumed that the succeeding species is not only a highly competitive wood decomposer but also a mycoparasite feeding on the preceding species. To investigate the interaction between A. citrinella and the putative host F. pinicola, the species were grown in dual cultures at different temperatures (5–25 °C). The interaction tests were complemented with qualitative enzymatic tests for both species and microscopic examination of the interaction zone. In the dual cultures, A. citrinella replaced F. pinicola only at low temperature (5 °C); at higher temperatures (25 °C), it was vice versa. Light microscopy revealed preferential growth of A. citrinella toward F. pinicola, hyphal contact, and finally death of F. pinicola hyphae. Enzymatic tests showed that A. citrinella is capable to degrade extracellular proteins, chitin, cellulose, and lignin. We interpret the interaction as mycoparasitism, as we suggest that A. citrinella is capable to recognize, kill, and feed from F. pinicola, beside its ability to degrade woody substrates. The results are discussed in an ecological context.