Strategies for the growth of fungi under conditions of nitrogen deficiency

Xylotrophic fungi are in the focus of scientists because of their capacity to grow under conditions of marked nitrogen deficiency. Basidiomycetes growing on wood developed some strategies that allow them find and consume nitrogen not easy accessible for many other organisms. In our experiments it was demonstrated that xylotrophic fungi, in contrast to basidiomycetes preferred rich organic substrates, are capable of not only prolonged searching growth (f-growth or forage growth) but also developed specific strategy to life in the wood (x-growth or xylotrophic growth). F-growth is characterized by a predominant use of resources accumulated by fungal mycelium before — that is such kind of growth is limited. X-growth is quite similar to f-growth but it is required additional nitrogen consumption and let the fungus occupy wooden substrates without limitation. Both types of growth are required recycling, but xylotrophic basidiomycetes belonging to different ecological groups use not compatible strategies to get nitrogen. While oyster mushroom could search for the rich nitrogen sources (living micro- and macroorganisms and so on) aphyllophoroids are able to extract of the trace nitrogen and include it in the recycling.Работа выполнена при финансовой поддержке РФФИ (проекты 12–04–00684, 14–04–00864, 15–04–06881) и Программы научного развития МГУ (ПНР–10)

Basidiomycete Quambalaria cyanescens in association with birch: distribution, phylogeny, ultrastructural characteristics

Basidiomycete Quambalaria cyanescens (Quambalariaceae, Microstromatales, Exobasidiomycetidae, Exobasidiomycetes, Ustilaginomycotina, Basidiomycota) was known earlier mainly as a symbiont of plants of the genera Eucalyptus and Corymbia on the Australian continent. Now it was found in association with silver birch in the territory of Moscow and Moscow Region. Q. cyanescens is revealed most frequently on the surface and inside thyrsus, in pollen samples, and less frequently on the surface of leaves and shoots. DNA profiling provided the evidence for the phylogeographical structure of the species. Further studies revealed Q. cyanescens in the samples collected in Cheboksary (Russia) and in Nessebar (Bulgaria). The list of regions where Q. cyanescens was found in association with birch steadily extends and embraces different geographical zones. The structure of the septal apparatus is of great importance for basidial fungi taxonomy. The mycelium of our isolates contained dolipore septa with thickenings around the pore channel characteristic for the type strain of Q. cyanescens. Accumulated data prove close association between birch and Q. cyanescens that warrant further investigation