Variability of decomposing ability among fungi associated with the bleaching of subtropical leaf litter

A diverse array of fungi take part in decomposition, but the variability of their decomposing ability is not fully understood. A total of 49 isolates of Ascomycota and Basidiomycota were obtained from bleached areas of leaf litter in a subtropical forest in southern Japan, and their ability to decompose leaves and recalcitrant compounds was quantified in pure culture. Mass loss of leaves of Castanopsis sieboldii (Fagaceae) and Schima wallichii (Theaceae) was evaluated at 20 C for 12 wk in vitro. Fungi caused a loss of -0.4% to 34.3% of the original leaf mass. The greatest mass loss was caused by four isolates of Mycena (Tricholomataceae). Isolates of Lachnocladiaceae caused greater mass loss of recalcitrant compounds, registered as acid-unhydrolyzable residue (AUR), which includes lignin, relative to Xylariaceae. Isolates of Rhytismataceae, Lachnocladiaceae, Marasmiaceae, and Omphalotaceae exhibited selective decomposition of AUR, Mycena exhibited simultaneous decomposition of AUR and components other than AUR, and Xylariaceae exhibited selective decomposition of components other than AUR. Mass losses of leaves and AUR caused by each fungal isolate were similar for C. sieboldii and S. wallichii. The Mycena isolates obtained from C. sieboldii caused greater mass losses of leaves and AUR than those obtained from the other tree species, suggesting a home-field advantage of decomposing potentialities, with implications for natural interactions beyond the in vitro system evaluated here.

Automated summary

A study revealed that different fungi have varied abilities in decomposing leaves and recalcitrant compounds, with Mycena species showing the highest mass loss. Some fungi exhibit selective decomposition of recalcitrant compounds, while others can simultaneously decompose both recalcitrant compounds and other components.