Evolutionary Processes Affecting Adaptation to Saprotrophic Life Styles in Ascomycete Populations
An understanding of sources of phenotypic variation in natural ascomycete populations is critical to the evaluation of criteria for taxonomic delimitation. Such variation may reflect genetic differences between individuals due to mutational and recombinatorial processes, or result from epigenetic changes in developmental patterns within heterogeneous habitats.
Amongst saprotrophic fungi, the degree to which an organism is adapted to colonization of disturbed or undisturbed habitats may influence its breeding biology and somatic development. Disturbance imposes R-selection, favouring organisms that are quick to arrive at newly available domains and to exploit readily assimilable resources, hence reducing genetic and epigenetic variation. Organisms that colonize undisturbed habitats are S- or C-selected, being able respectively to survive selectively stressful conditions or a potentially high incidence of competitors; they tend to exhibit both genetic and epigenetic variation.
Patterns of variation amongst ascomycete populations and individuals are discussed in relation to environmental heterogeneity and compared with those exhibited by basidiomycetes. Possible mechanisms resulting in phenotypic instability are introduced, and the basis for general differences between ascomycetes and basidiomycetes.
KeywordsFungal Community Saprotrophic Fungus Mycological Research British Mycological Society Undisturbed Habitat
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- Ainsworth, A.M., A.D.M. Rayner, S.J. Broxholme, J.R. Beeching, J.A. Pryke, P.T. Scard, J. Berriman, K.A. Powell, A.J. Floyd, and S.K. Branch, 1990b, Production and properties of the sesquiterpene, (+)-torreyol, in degenerative mycelial interactions between strains of Stereum, Mycological Research 94: 799–809.CrossRefGoogle Scholar
- Anderson, J.B., L.M. Kohn, and J.F. Leslie, 1992, Genetic mechanisms in fungal adaptation, In: The Fungal Community (G.C. Carroll and D.T. Wicklow, eds): 73–98. Marcel Dekker, New York.Google Scholar
- Andrews, J.H., 1992, Fungal life-history strategies, In: The Fungal Community (G.C. Carroll and D.T. Wicklow, eds): 119–145. Marcel Dekker, New York.Google Scholar
- Boddy, L. and G.S. Griffith, 1989, Role of endophytes and latent invasion in the development of decay communities in sapwood of angiospermous trees, Sydowia 41: 41–73.Google Scholar
- Brasier, C.M., 1987, The dynamics of fungal speciation, In: Evolutionary Biology of the Fungi (A.D.M Rayner, C. M. Brasier and D. Moore, eds): 231–260. Cambridge University Press, Cambridge.Google Scholar
- Brasier, C.M. and A.D.M. Rayner, 1987, Whither terminology below the species level in fungi?, In: Evolutionary Biology of the Fungi (A.D.M. Rayner, C.M. Brasier and D. Moore, eds): 379–388. Cambridge University Press, Cambridge.Google Scholar
- Cooke, R.C. and A.D.M. Rayner, 1984, Ecology of Saprotrophic Fungi, Longman, London.Google Scholar
- Crawford, J. and K. Ritz, 1993, Origin and consequence of colony form in fungi: a reaction-diffusion mechanism for morphogenesis, In: Shape and Form in Plants and Fungi (D.S. Ingram, ed.): in press. Academic Press, London.Google Scholar
- Dowson, C.G., A.D.M. Rayner, and L. Boddy, 1988, Foraging patterns of Phallus impudicus, Phanerochaete laevis and Steccherinum fimbriatum between discontinuous resource units in soil, FEMS Microbiology Ecology 53: 291–298.Google Scholar
- Pritchard, D.J., 1986, Foundations of Developmental Genetics, Taylor and Francis, London.Google Scholar
- Prosser, J.I., 1991, Mathematical modelling of vegetative growth of filamentous fungi, In: Handbook of Applied Biology, Vol. 1 (D.H. Arora, B. Rai, K.J. Mukerji and G.R. Knudsen, eds): 591–623. Marcel Dekker, New York.Google Scholar
- Rayner, A. D.M., 1990, Natural genetic transfer systems in higher fungi, Transactions of the Mycological Society of Japan 31: 75–87.Google Scholar
- Rayner, A.D.M. and L. Boddy, 1988, Fungal Decomposition of Wood, John Wiley, Chichester.Google Scholar
- Rayner, A.D.M. and D. Coates, 1987, Regulation of mycelial organisation and responses, In: Evolutionary Biology of the Fungi (A.D.M., Brasier, and D. Moore, eds): 115–136. Cambridge University Press, Cambridge.Google Scholar
- Rayner, A.D.M., G.S. Griffith, and H.G. Wildman, 1993, Differential insulation and the generation of mycelial patterns, In: Shape and Form in Plants and Fungi (D.S. Ingram, ed.): in press. Academic Press, London.Google Scholar
- Rayner, A.D.M. and I.K. Ross, 1991, Sexual politics in the cell, New Scientist 129: 30–33.Google Scholar
- Rayner, A.D.M., R. Watling, and J.C. Frankland, 1985, Resource relationships — an overview, In: Developmental Biology of Higher Fungi (D. Moore, L.A. Casselton, D.A. Wood and J.C. Frankland, eds): 1–40. Cambridge University Press, Cambridge.Google Scholar
- Rayner, A.D.M. and J.F. Webber, 1984, Interspecific mycelial interactions — an overview, In: The Ecology and Physiology of the Fungal Mycelium (D.H. Jennings and A.D.M. Rayner, eds): 383–417. Cambridge University Press, Cambridge.Google Scholar
- Sharland, P.R., 1987, Mycelial Biology of Xylariaceous Fungi, PhD thesis, University of Bath.Google Scholar
- Trinci, A.P.J., 1978, The duplication cycle and vegetative development in moulds, In: The Filamentous Fungi, Vol. 3 (J.E. Smith and D.R. Berry, eds): 132–163. Edward Arnold, London.Google Scholar
- Wessels, J.G.H., 1991, Fungal growth and development: a molecular perspective, In: Frontiers in Mycology (D.L. Hawksworth, ed.): 27–48. CAB International, Wallingford.Google Scholar