Monocaryotization of Cultures of Lenzites trabea (Pers.) Fr. and other Wood-destroying Basidiomycetes

Abstract

Cultures of Lenzites trabea and some other basidiomycetes grown on nutrient agar containing high concentrations of sodium arsenate consistently reverted from the dicaryotic to the monocaryotic condition. This effect could also be induced by a wide variety of other toxicants, including copper sulphate, zinc sulphate, sodium dichromate, sodium pentachlorophenate, creosote, crystal violet, boric acid, and sodium taurocholate, but sodium arsenate was the most reliable monocaryotizing agent, being effective with eight of the fourteen basidio-mycete species tested with it. The neohaplonts formed by sodium arsenate and other toxicants mate normally with each other and with compatible monospore isolates. The value of chemical monocaryotization as a technique in fungal genetics and experimental taxonomy is discussed. By using the mating factor alleles as genetic markers, it was demonstrated that when L. trabea is monocaryo-tized by sodium arsenate or copper sulphate, only one of the two nuclei in the dicaryon can be recovered in the neohaplonts, the direction of this complete nuclear selection depending on the toxicant and the dicaryon concerned. It was shown to occur in treated wood blocks during routine soil-block decay tests of inorganic wood preservatives and it is probably a frequent, though hitherto unrecognized, occurrence in the laboratory testing of wood preservatives and other fungicides against basidiomycetes.