Organic Nitrogen Supplementation Increases Vegetative and Reproductive Biomass in a Versatile White Rot Fungus

The Black Poplar Mushroom Cyclocybe aegerita (syn. Agrocybe aegerita) is a white-rot fungus that naturally fruits from woody substrates, including buried wood. It is known for its substrate versatility and is equipped with a respective carbohydrate-active enzyme repertoire being intermediate between typical white-rot fungi and plant litter decomposers. Given relative nitrogen scarcity in wood, mobilization of nitrogen from surrounding litter is known as a way to meet nitrogen requirements for cellular homeostasis and reproduction of wood decay fungi. However, the effect of added nitrogen on vegetative and reproductive biomass has not yet been studied in a uniform minimalistic laboratory setup. For C. aegerita, such a growth and fruiting setup has been developed. In the present study, this white-rot fungus has been grown with and without additional beta-adenosine, an organic nitrogen source present in plant litter. Elevated beta-adenosine levels increased aerial mycelium weight by 30% (1 x beta-adenosine) and 55% (10 x beta-adenosine), reproductive biomass by 75% (1 x beta-adenosine) and by 100% (10 x beta-adenosine), number of primordia by 127% (10 x beta-adenosine) and accelerated primordium formation by 1.6 days (10 x beta-adenosine), compared to the control treatment. These findings imply that C. aegerita invests additional organic nitrogen resources into direct vegetative and reproductive biomass build-up at the same time. Colonization of niches with accessory nitrogen sources, like buried wood, which is near the plant litter layer, may thus provide an evolutionary fitness advantage. Globally anthropogenically altered nitrogen dynamics may affect hyphal-driven processes as well as fruit body-driven food webs.

Automated summary

The Black Poplar Mushroom Cyclocybe aegerita is a white-rot fungus that can naturally grow and reproduce from woody substrates. It has the ability to decompose both leaf litter and needle litter, aided by carbohydrate-active enzymes. It has been found that the addition of nitrogen can significantly enhance the growth and reproduction of this fungus.