Intraspecific Antagonism - Fungal Individualism

Fungal Individualism

Zone lines form in wood for many reasons, including host reactions against parasitic encroachment, and inter-specific interactions, but the lines observed by Rayner and Todd when transversely-cut sections of brown-rotted birch tree trunk or branch were incubated in plastic bags appeared to be due to a reaction between different individuals of the same species of fungus.

This was a startling inference at a time when the prevailing orthodoxy within the mycological community was that of the "unit mycelium". This was the theory that when two different individuals of the same species of basidiomycete wood rotting fungi grew and met within the substratum, they fused, cooperated, and shared nuclei freely. Rayner and Todd's insight was that basidiomycete fungi individuals do, in most "adult" or dikaryotic cases anyway, retain their individuality.

A small stable of postgraduate and postdoctoral students helped elucidate the mechanisms underlying these intermycelial interactions, at Exeter University (Todd) and the University of Bath (Rayner), over the next few years.