Lecture #8

The Fungal Individual


Alan Rayner - University of Bath - individualistic mycelium
A.H.R. Buller - unit mycelium

Self vs. nonself reactions - individual identities

Mycelium capable of indeterminant growth

One of the major challenges facing a mycelium is encountering other mycelia of the same or similar species

Things a mycelium must do:

Individualistic mycelium- mycelium is more than simple, additive assemblage of hyphae

Correlation between septation and anastomosis

Self-fusions

Non-self fusion

Physiological access - resulting from protoplasmic continuity; may allow redistribution of resources between systems in response to the formation of source-sink gradients

Genetic access - results in the mixing of nuclear and mitochondrial (?) populations; potential invasion of one genetic system into another; somatic compatibility is a trade off between two mycelia being cooperative but may result in the genetic "extinctio n" of one genotype; what does this say about fitness

Mechanisms that prevent or restrict physiological or genetic access following nonself anastomosis

SI in basids

Individualistic mycelium - involves somatic rejection responses as a mechanism for maintaining the identity of individual mycelia within natural populations by preventing physiological integration with others of different genetic origin.

2 spores germinating to produce primary mycelium, fuse to produce secondary mycelium that encounters other secondary mycelia

wood decay example of Pleurotus with nematode trapping and bacterial scavenging

contrary to established theory - the unit mycelium: hyphal fusions generated physiologically unified, cooperative genetic mosaics in natural populations

unit mycelium developed by Buller 1934 with the inbreeding system Coprinus sterquilinus

somatic compatible units called genets and not clones

two SI secondary mycelia may go on to produce basidiomata, basidiospores and primary mycelia that are mating compatible

Do nuclei and mitochondria behave similarly in fusions?

Deleterious consequence of nonself access:


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