Spatio-Temporal Dynamic of Tuber magnatum Mycelium in Natural Truffle Grounds

Abstract

Tuber magnatum produces the world's most expensive truffle. This fungus produces very rare ectomycorrhizas which are difficult or even impossible to detect in the field. A “real-time” PCR assay was recently developed to quantify and to track T. magnatum mycelium in soil. Here, this technique was used to investigate the spatial distribution of T. magnatum extra-radical mycelium in soil productive patches and its dynamic across seasons. This study was carried out in four different natural T. magnatum truffle grounds located in different Italian regions. During the fruiting seasons, the amount of T. magnatum mycelium was significantly higher around the fruiting points and decreased going farther away from them. Moreover, T. magnatum mycelium inside the productive patches underwent seasonal fluctuations. In early spring, the amount of T. magnatum mycelium was significantly higher than in summer. In summer, probably due to the hot and dry season, T. magnatum mycelium significantly decreased, whereas in autumn it increased again and was concentrated at the putative fruiting points. These results give new insights on T. magnatum ecology and are useful to plan the most appropriate sampling strategy for evaluating the management of a truffle ground.

Soil microclimate changes affect soil fungal communities in a Mediterranean pine forest

“…By contrast, studies of subarctic and alpine tree line ecosystems have reported that warming may cause important fungal community shifts and changes in soil fungal biomass, because higher temperatures may stimulate nutrient cycling and plant production (Clemmensen et al ., ; Solly et al ., ). Here, soil fungal biomass was lower during summer than during autumn and spring, supporting previous reports from other Mediterranean forest ecosystems (Iotti et al ., ; Castaño et al ., ; Queralt et al ., ) and potentially reflecting differences between Mediterranean and boreal forest ecosystems.…”

“…Mycorrhizal species have shown contrasting responses to changes in climate, and responses are modulated by nutrient availability (Clemmensen et al, 2006;Solly et al, 2017) and host tree responses (Fernandez et al, 2016;Hartmann et al, 2017). Recent studies of Mediterranean ecosystems have suggested that the biomass of some ECM species is dynamic across seasons, and that mycelial production is often halted during summer and winter (Iotti et al, 2014;Castaño et al, 2017;Queralt et al, 2017). For example, by simulating future increases in summer drought in Mediterranean areas, we recently predicted sharp decreases in Lactarius vinosus soil biomass during summer but increases during winter-spring (Castaño et al, 2017).…”

Lactarius deliciosus Fr. soil extraradical mycelium correlates with stand fruitbody productivity and is increased by forest thinning

“…We would expect the variation among years to be due to weather variables. These results contribute to the controversy of whether --or when--the amount of mycelium is related to presence of fruiting bodies (Iotti et al, 2014;Guidot et al, 2003) or not (De la Varga et al, 2013), or it may be in some cases (Van der Linde et al, 2009). Further testing could confirm the reliability of this variable as a predictor of the potential sporocarp production of a particular fungal species.…”

Ecological and Genetic Advances in the Cultivation of Tuber Spp.

“…Recently, methods have been developed to identify and quantify T. magnatum mycelium in the soil by Iotti et al (2012). Tuber magnatum mycelium was found to form large patches in productive areas (Zampieri et al, 2010), and using real time PCR, it was possible to determine its spatiotemporal dynamics (Iotti et al, 2014). It was found that T. magnatum mycelium is particularly abundant and widespread in spring and tends to concentrate in the productive areas during fruiting (autumn) (Iotti et al, 2014).…”