Formation of hyphal loops in xylotrophic coprinoid mushrooms

Abstract

Recent molecular analysis split the traditional genus Coprinus (Homobasidiomycetes) into four distinct genera: Coprinus, Coprinopsis, Coprinellus and Parasola. Coprinoid mushrooms are usually saprotrophic on soil and/or dung of herbivores. However, more than 60 species are able to grow on wood and straw. Xylotrophic mushrooms are forcing a relatively short supply of nitrogen and phosphorous nutrients. Coprinus comatus has been reported to produce specialized structures (“spiny balls”) to penetrate nematodes for nutrient supply (Luo et al. 2004, Mycologia 96, 1218-1224). Nematode traps of other fungi involve adhesive hyphal network and knobs, hyphal loops and snares. Toxin production may support in nematode immobilisation. Nematode-trapping species belong mainly to the mitosporic Deute romy - ce tes, but some are also found amongst Zygomycetes and Basidiomycetes. We have observed hyphal loops in several wood-decaying basidiomycetes, such as Daedalea quercina, Ganoderma lucidum, Lentinula edodes, Piptoporus betulinus and Pleurotus ostreatus. Furthermore, regular and irregular hyphal loops and/or rings were observed in the four clades of Coprinoid species (Coprinus comatus, Coprinellus angulatus, C. bisporus, C. curtus, C. domesticus, C. disseminatus, C. ellissi, C. micaceus, C. xanthothrix, Coprinopsis cinerea, C. gonophylla, C. radians, C. strossmayeri, C. scobicola, and P. plicatilis). Hyphal loops were particularly often formed in Coprinellus species. Such structures were rare in Coprinopsis atramentaria, C. cothurnata, C. romagnesiana, C. psychromorbida and Coprinus patouillardii (an unclassified isolate). It is not clear yet why Basidiomycetes fungi have these structures. Is it that many species have nematode trapping abilities by formation of such structures? Thanks to the DAAD, NATO and the Deutsche Bundesstiftung Umwelt for financial support.