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Intraspecific antagonism means a disharmonious or antagonistic interaction between two
individual An individual is that which exists as a distinct entity. Individuality (or self-hood) is the state or quality of being an individual; particularly (in the case of humans) of being a person unique from other people and possessing one's own Maslow ...
s of the same species. As such, it could be a sociological term, but was actually coined by
Alan Rayner Alan Rayner (born 1950) is a British biologist and educator. Biography Rayner was born in Nairobi, Kenya, as the youngest of two children. His mother was the Deputy Mayor of Nairobi and his father was a Plant Pathologist, working on coffee rust ...
and
Norman Todd Norman Douglas Todd (11 June 1884 – 12 May 1959) was an English cricketer who played first-class cricket for Derbyshire in 1906 and 1908 Todd was born at Hetton-le-Hole, County Durham. He made his debut for Derbyshire in the 1906 season, ...
working at Exeter University in the late 1970s, to characterise a particular kind of
zone line Zone or The Zone may refer to: Places Climate and altitude zones * Death zone (originally the lethal zone), altitudes above a certain point where the amount of oxygen is insufficient to sustain human life for an extended time span * Frigid zone, ...
formed between wood-rotting fungal mycelia. Intraspecific antagonism is one of the expressions of a phenomenon known as vegetative or somatic incompatibility.


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 Mycology is the branch of biology concerned with the study of fungi, including their genetic and biochemical properties, their taxonomy and their use to humans, including as a source for tinder, traditional medicine, food, and entheogens, as w ...
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.


Applications of intraspecific antagonism

Although the attribution of individual status to the mycelia confined by intraspecific zone lines is a comparatively new idea, zone lines themselves have been known since time immemorial. The term spalting is applied by woodworkers to wood showing strongly-figured zone lines, particularly those cases where the area of "no-man's land" between two antagonistic conspecific mycelia is colonised by another species of fungus.
Dematiaceous “Black yeasts”, sometimes also black fungi, dematiaceous fungi, microcolonial fungi or meristematic fungi is a diverse group of slow-growing microfungi which reproduce mostly asexually (fungi imperfecti). Only few genera reproduce by budding ...
hyphomycetes, with their dark-coloured mycelia, produce particularly attractive black zone lines when they colonise the areas occupied by two antagonistic basidiomycete individuals. Spalted wood can be difficult to work, since different individual wood-rotting fungi have different decay efficiencies, and thus produce zones of different softness, and the zone lines themselves are usually unrotted and hard. Instraspecific antagonism can also sometimes be of assistance in quickly recognising the membership of clones in those fungi, particularly root-rots such as Armillarea where individual mycelia may colonise large areas, or more than one tree. It is even the subject of a recent paten


References

{{Reflist, colwidth=30em, refs= {{cite journal , author=Worral, J.J. , year=1997 , title=Somatic incompatibility in Basidiomycetes , journal=Mycologia , volume=89 , issue=1 , pages=24–36 , doi= 10.2307/3761169, jstor=3761169 {{cite book , author=Burnett J.H. , title=Fundamentals of Mycology , publisher=Arnold Publishers , location=London , year=1976 {{cite journal , author1=Rayner, A D M , author2=Todd, N K , year=1977 , title=Intraspecific antagonism in natural populations of wood-decaying basidiomycetes , journal=J. Gen. Microbiol. , volume=103 , pages=85–90 , doi= 10.1099/00221287-103-1-85, doi-access=free {{cite journal , author1=Rayner, A D M , author2=Todd, N K , year=1979 , title=Population and community structure and dynamics of fungi in decaying wood , journal=Advances in Botanical Research , volume=7 , pages=333–420 , doi= 10.1016/s0065-2296(08)60090-7, isbn=9780120059072 Mycology Fungal morphology and anatomy Wood