Larger basidiomycetes growing on poroid lignicolous fungi show rot type-related colonization patterns

Abstract

Poroid fungi that grow on the wood are frequently associated with other basidiomycetes that are often used as a substrate, also during fungal succession. This lifestyle has differing evolutionary origins, going back at least 100 million years. The use of fungal tissue as a substrate indicates that some fungicolous taxa could benefit from the higher nutrient contents compared to wood. These life modes relate to the dead and live fruiting bodies of the hosts. It may take forms such as commensalism, replacement, saprotrophy, displacement, and parasitism. These modes, often driven by competitive processes, imply different strategies that, in most cases, may be linked to the degrading capacities (rot types) of colonizers and hosts, i.e., to their enzymatic repertoire. This repertoire often includes glucanases, which are potentially able to cleave structural glucans of fungi. For investigating these assumptions, a compilation of published data of 95 taxa recorded in temperate and boreal biomes of the northern hemisphere was analyzed. A conspicuous, previously unpublished observation was that the members of most associations showed a higher ratio of white rotters than those among wood fungi in general. This phenomenon points to their highly developed enzymatic competence, which may also explain saprotrophy on dead fruit bodies. Future research should, above all, investigate molecular mechanisms involved in mycotrophic basidiomycetes.