Changes in production of lignin degrading enzymes during interactions between mycelia of the tropical decomposer basidiomycetes Marasmiellus troyanus and Marasmius pallescens

Abstract

During the interaction of two tropical agaric fungi, Marasmius pallescens and Marasmiellus troyanus, on agar media, initial deadlock between the two mycelia was ultimately followed by take-over by M. troyanus. When shaken liquid cultures of these two fungi were mixed, a rapid increase in laccase and manganese peroxidase activity, but no lignin peroxidase, was detected in the culture supernatant. Even more rapid and elevated induction of laccase occurred when filter-sterilized supernatant of Marasmius pallescens was added to Marasmiellus troyanus cultures, but the reciprocal experiment (addition of M. troyanus supernatant to M. pallescens cultures), did not lead to any increase in laccase activity. Addition of autoclaved supernatant of M. pallescens also induced laccase activity from M. troyanus cultures, but over a period of days rather than hours. Although both M. troyanus, and to a lesser extent M. pallescens, are able to produce laccases in shaken liquid culture following addition of the inducer 2,5-dimethylalanine, these experiments suggest that the presence of heat-stable and heat-labile laccase inducers secreted by M. pallescens mycelia lead to induction of laccases by M. troyanus.