Purahong Witoon, Tanunchai Benjawan, Ji Li, Stellmach Hagen, Hilman Boaz, Schulze Ernst-Detlef, Hause Bettina, Tarkka Mika, Buscot François, Herrmann Sylvie
UFZ-Helmholtz Centre for Environmental Research, Department of Soil Ecology, Halle (Saale), Germany.
Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany.
Commun Biol. 2025 Sep 16;8(1):1344. doi: 10.1038/s42003-025-08762-w.
Besides their symbiotic association with tree rootlets, ectomycorrhizal (EM) fungi have been commonly detected in nature in deadwood and plant debris of various tree species. However, their potential dual roles as symbiotrophs and saprotrophs are still debated. Here, we provide evidence from a series of experiments on the plasticity of symbiotrophic-saprotrophic lifestyles of the ectomycorrhizal fungus Piloderma croceum associated with Quercus robur L. Specifically, we find that P. croceum efficiently colonizes deadwood of oak in an experimental system without living oak. Results based on the productions of hydrolytic enzymes and corticrocin as well as the C content in deadwood and mycelium of P. croceum demonstrate its capability of wood decomposition and assimilation of C from the decomposing wood. Our results also show that in presence of wood pieces colonized by saprotrophic mycelium of P. croceum, the roots of oak plants develop true EM symbiosis with Hartig net formation. Collectively, our results indicate a role for mycelium growing in deadwood as an underestimated EM fungus propagule bank, suggesting that deadwood and other decomposing plant material may indirectly influence the productivity of forest ecosystems by contributing to the recruitment of mycorrhizal fungi, thereby enhancing plant nutrient acquisition.
除了与树根形成共生关系外，外生菌根（EM）真菌在自然界中还普遍存在于各种树种的枯木和植物残体中。然而，它们作为共生生物和腐生生物的潜在双重作用仍存在争议。在此，我们通过一系列实验提供证据，证明与欧洲栓皮栎相关的外生菌根真菌黄皮丝膜菌具有共生营养-腐生营养生活方式的可塑性。具体而言，我们发现黄皮丝膜菌在没有活栓皮栎的实验系统中能有效地定殖于橡木枯木。基于水解酶和皮质菌素的产生以及黄皮丝膜菌枯木和菌丝体中碳含量的结果表明，它具有分解木材并从分解的木材中同化碳的能力。我们的结果还表明，在存在被黄皮丝膜菌腐生菌丝定殖的木片的情况下，栓皮栎植物的根会与哈蒂氏网形成真正的外生菌根共生关系。总体而言，我们的结果表明，在枯木中生长的菌丝体作为一种被低估的外生菌根真菌繁殖体库发挥着作用，这表明枯木和其他正在分解的植物材料可能通过促进菌根真菌的募集来间接影响森林生态系统的生产力，从而增强植物对养分的获取。
