Truffles are hypogeous ascomycetous fungi belonging to Tuber genus, which form ectomycorrhizal association with oak, hazel and beech. The expensive edible mushrooms are known for its unique flavour and smell. The role of microbial communities associated with truffles are rather unknown. The aim of the project is to understand the effect of soil and microorganisms on cultivation of Tuber on truffle field sites.
There were two different type of sampling sites in Thüringia- two test field sites and a natural site. Both the test field sites were treated with truffle growth supplements- Truf up and Rhizovital. Soil community analyses and element analyses of test field and natural sites were done along with isolation of microorganisms from soil nearby of fruiting bodies and the gleba of fruiting bodies of the natural site. Interaction studies of T. borchii with isolated bacteria was carried out in Petri dishes under different conditions. Based on the results of interaction with T. borchii, a consortia was prepared and applied it on the test field sites.
Soil community analysis of natural site revealed dominance of Proteobacteria, Actinomycetia, Mortierellomycetes, Sordariomycetes and Dothideomycetes. Whereas in test field sites, lower diversity was found. After three years, the microbial community had a significant rise of Tremellomycetes and a drop of Mortierellomycetes in the treatment plots.
A strain collection with 355 microorganisms contained predominantly of Streptomyces sp., Pseudomonas sp. and Bacillus sp were created from the soil and fruiting bodies of natural sites. First analyses of bacterial interaction with truffles showed that species of Proteobacteria and Actinobacteria induced faster growth of truffle mycelium with visible mycelium after 4 days interaction. Moreover, the absence of light showed a positive growth of truffle mycelium, when compared with light conditions.
Over the span of three years, a change in the microbial communities in the test field sites were observed which were similar with natural sites of truffles. Along with that, the interaction of truffle helper bacteria with truffles were effective, which were then used as consortia for the test field sites.