Cycling in Degradation of Organic Polymers and Uptake of Nutrients by a Litter-Degrading Fungus

SummaryWood and litter degrading fungi are the main decomposers of lignocellulose and thus play a key role in carbon cycling in nature. Here we provide evidence for a novel lignocellulose degradation strategy employed by the litter degrading fungusAgaricus bisporus(known as the white button mushroom). Fusion of hyphae allows this fungus to synchronize the activity of its mycelium over large distances (50 cm). The synchronized activity has an 13-hour interval that increases to 20 h before becoming irregular and is associated with a 3.5-fold increase in respiration while compost temperature increases up to 2 °C. Transcriptomic analysis of this burst-like phenomenon supports a cyclic degradation of lignin, deconstruction of (hemi-) cellulose and microbial cell wall polymers, and uptake of degradation products during vegetative growth ofA. bisporus. Cycling in expression of the ligninolytic system, enzymes involved in saccharification, and nutrient uptake is proposed to provide an efficient way for degradation of substrates such as litter.