Volume 12 Part 1 Article 19: Characterization of Ganoderma lucidom by Di-Mon Mating

Volume 12 Part 1 Article 19
Year 1989
Title: Characterization of Ganoderma lucidom by Di-Mon Mating
Authors: R.S. Hseu and H.H. Wang


The Ganoderma species are wood decaying fungi that cause white rots of a wide variety of trees and timber on a world wide basis. In the oriental countries, such as China, Japan and Korea, the fruiting body of Ganoderma has been a popular traditional medicine to cure various human diseases, such as hepatitis, hypertension, hypercholesterolemia and gastric cancer, for a long time. Recent findings, that certain types of fungal (1 – 3)-B-Dglucans have antitumor activity, have directed attention toward the polysaccharide components of the fruiting body of G. applanatum (Pers.) Wallr. (Sasaki et al., 1971; Usui et al., 1983), G. lucidum (W. Curt.: Fr.) Karst. (Ito et al. , 1977; Miyazaki et al., 1981; Sone et al. , 1985) and G. japonicum Imaz. (Ukai et al., 1983).

Ganoderma was established by Karsten (1881) with G. lucidum as the type species. There are some intensive works on the taxonomy of the genus (Donk, 1960; Steyaert, 1980) based on brightness of the pileus and the morphology of the basidiospores. Nobles (1955) published the keys for the identification of wood inhabiting Hymenomycetes. The descriptions of the cultural characteristics of Ganoderma species are very similar to each other. Nobles suggested to use interfertility tests as an aid to determine the identity of species.

Bazzalo and Wright (1982) reported that G. lucidum is a complex of very similar species. Hseu and Wang (1986) used the API-ZYM enzyme testing system for the identification of cultures of Ganoderma. It was found that the patterns of extracellular enzyme activities were significantly different, and that the cultures of G. lucidum could be classified into four groups on the basis of the enzyme tests. Buller (1930) first reported the dikaryotization of homokaryons by dikaryons. Quintanilha (1937) termed this mode of dicaryotization as the Buller phenomenon or di-mon matings. It was established that hyphal fusions ocurred between homokaryons and dikaryons and that nuclei could be transferred to the former. The regular and rapid dikaryotization of homokaryons by dikaryons was observed to occur according to predictions based on the same species.

Because of the low percentage or total lack of basidiospore germination, homokaryons of G. lucidum have been difficult to obtain. The objectives of our study were to determine the identity of G. lucidum isolates by the di-mon mating system, that might provide a more firm basis for clarifying the taxonomy of cultures of G. lucidum.

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