6 Wood Discoloration

2.4 Identification 31
In addition to the pairing of compatible monokaryons to insert genetic
material in a fungus from another isolate, fusion of fungal protoplasts can be
performed. Protoplast fusion can be used to make hybrids between cells of the
same mating type, as well as of dikaryotic cells or even between species and genera.
Spheroplasts (cell wall partially removed by lysing enzymes) or protoplasts
(cell wall completely removed) fuse by electric influence or through osmotic
active substances (polyethylene glycol) and some of them regenerate to new
hyphae. Protoplast fusion is used for genetic studies as well as for isolate improvement.
Experiments on wood fungi comprise, e.g., Auricularia polytricha,
Gloeophyllum trabeum, Heterobasidion annosum, Lentinula edodes, Oligoporus
placenta, Ophiostoma piceae, O. ulmi, Phanerochaete chrysosporium, Pleurotus
ostreatus, Trametes versicolor, and Trichoderma spp. (Nutsubidze et al. 1990;
Trojanowski and Hüttermann 1984; Royer et al. 1991; Sunagawa et al. 1992;
Rui and Morrell 1993; Richards 1994; Tokimoto et al. 1998; Bartholomew et al.
2001; Xiao and Morrell 2004). Interspecific fusions (Toyomasu and Mori 1989;
Eguchi and Higaki 1992) and intergeneric fusions (Liang and Chang 1989) were
reported. With increasing genetic distance of the fusion partners, however, the
hybrids are instable, do no fruit, die, or the obtained fruit bodies correspond to
one of the parents, that is, obviously one of the two nuclei has been eliminated
before.
Protoplasts have been produced from O. piceae with the aim of subsequently
inserting genetic material capable of producing fluorescent proteins to allow visualization
of hyphae of that species in wood by using fluorescence microscopy
(Xiao and Morrell 2004).
2.4
Identification
2.4.1
Traditional Methods
Determination keys and descriptions for Deuteromycetes are based on morphology,
color, and development (conidiogenesis) of conidia and conidiogenous
cells (Figs. 2.8–2.10) (Carmichael et al. 1980; Domsch et al. 1980; v. Arx
1981; Wang 1990; Hoog and Guarro 1995; Schwantes 1996; Kiffer and Morelet
2000; Samson et al. 2004).
The fruit bodies of Ascomycetes and Basidiomycetes serve to identify species
on the basis of macro- and microscopic characteristics using keys or illustrated
books: Kreisel 1961; Domański 1972; Domański et al. 1973; Breitenbach and
Kränzlin 1981, 1986, 1991, 1995; Moser 1983; Jülich 1984; Hanlin 1990; Jahn
1990; Wang and Zabel 1990; Ryvarden and Gilbertson 1993, 1994; Huckfeldt
and Schmidt 2005; yeasts: Barnett et al. 1990). There are identification kits
www.taq.ir