Feeding of Agaricus bisporus Mushrooms is Impacted by Mycelium Colonization Time and Network Architecture

Mycelial nutrient uptake and transport sustain mushroom growth, yet the physical factors constraining long-distance translocation in Agaricus bisporus remain poorly understood. For instance, the bottom compost stratum is underutilized by the fungus to support its mushroom production. We investigated how mycelial network architecture and colonization time influence nutrient flow during cultivation. Using stable isotope labeling, we quantified mushroom tracer uptake from the lower compost stratum in distinct culture setups. The total resource uptake by a mushroom is determined by the flow of resources to that mushroom and is affected by water and nutrient uptake by the vegetative mycelium in compost. Hydraulic resistance across the network limits this resource flow and consequently limits mushroom growth. We found that increasing cord abundance can counteract this limitation and enhance productivity when long-distance translocation is required due to local nutrient depletion. Extended colonization time increases total resource uptake, as longer growth periods enhance network density and substrate exploitation. We found that mushrooms within a flush heterogeneously feed from different compost strata, suggesting that fruiting bodies are heterogeneously connected to the mycelial network. For commercial cultivation, the findings highlight the importance of thorough substrate degradation and sufficient flow speed, achievable through extended colonization and cultivation.