Studies on the Systematics of Ectomycorrhizal Fungi in Axenic Culture. III. Patterns of Polyphenol Oxidase Activity

ABSTRACT

Five-week-old cultures of ectomycorrhizal fungi grown on four different agar media were tested for presence of lacease and tyrosinase using l-naphthol and p-cresol spot tests respectively. Ectomycorrhizal fungi could be placed into groups which reflected taxonomic affinity, based on the presence, absence or dominance of enzymes. For example, the Boletaceae exhibited an absence of lacease and most species also lacked tyrosinase activity, while in contrast, species of Lactarius were positive for laccase activity and in most cases positive for tyrosinase activity. Species of Amanita and Lacearia possessed tyrosinase but generally were negative for laccase activity. Different agar media were found to influence the results for individual species. The results reveal that these spot tests can be used as important taxonomic characters for differentiating cultures of ectomycorrhizal fungi particularly at the generic level. As well, these results correlate with those found for basidiomata by other authors. The possible role of polyphenol oxidases in the biology of ectomycorrhizal fungi is discussed.

Key Words:

• ectomycorrhizal fungi
• laccase
• tyrosinase
• cultures
• Agaricales
• identification
• systematics