ABSTRACT
Most studies on mushrooms are about cultivation methods. In contrast, genetic information on most mushroom species is scanty, except in the case of Agaricus bisporus (syn. A. brunnescens) (see Anderson, Chapter 10). Some morphological mutants of Lentinula edodes were isolated and characterized (Hasebe et al., 1982, 1987, 199; Murakami et al., 1987; Itavaara, 1990). However, these mutants usually do not have any commercial value. For wild and cultivated strains of mushroom species, strain characterization/typing has traditionally been based on morphological characters and physiological properties such as temperature optima. Recently, the introduction of biochemical markers, such as soluble protein profiles, 266various enzyme activities, serological properties (Kawamura & Goto, 1980; Ohmasa & Furukawa, 1986; Itavaara, 1988; Burdsall et al., 1990; Lin & Hsieh, 1991) and especially, isozyme profiles (see Royse & May, Chapter 11), represent a significant improvement in typing methodology since these techniques offer greater diversity. However, expression of these biochemical markers is still under physiological and genetic controls. Markers based upon DNA probes, on the other hand, are direct assessments of the constant genetic diversity of different strains and are dominant characters. DNA finger printing techniques have the potential to reveal an almost unlimited number of polymorphisms. One of the earlier methods is the widely used restriction fragment length polymorphisms (RFLPs) technique which uses specific DNA probes to identify single or low copy sequences in genomic DNA and shows allelic relationship among individuals by the presence or absence of restriction endonuclease sites in the examined sequence. Instead of using RFLPs, we initiated a molecular project on Lentinula edodes utilizing the recently established molecular technique, polymerase chain reaction (PCR), which was awarded “the molecule of the year” in 1989 (Guyer & Koshland, 1989).
