Seasonal dynamics of Boletus edulis and Lactarius deliciosus extraradical mycelium in pine forests of central Spain

Abstract

The annual belowground dynamics of extraradical soil mycelium and sporocarp production of two ectomycorrhizal fungi, Boletus edulis and Lactarius deliciosus, have been studied in two different pine forests (Pinar Grande and Pinares Llanos, respectively) in Soria (central Spain). Soil samples (five per plot) were taken monthly (from September 2009 to August 2010 in Pinar Grande and from September 2010 to September 2011 in Pinares Llanos) in eight permanent plots (four for each site). B. edulis and L. deliciosus extraradical soil mycelium was quantified by real-time polymerase chain reaction, with DNA extracted from soil samples, using specific primers and TaqMan® probes. The quantities of B. edulis soil mycelium did not differ significantly between plots, but there was a significant difference over time with a maximum in February (0.1576 mg mycelium/g soil) and a minimum in October (0.0170 mg mycelium/g soil). For L. deliciosus, significant differences were detected between plots and over time. The highest amount of mycelium was found in December (1.84 mg mycelium/g soil) and the minimum in February (0.0332 mg mycelium/g soil). B. edulis mycelium quantities were positively correlated with precipitation of the current month and negatively correlated with the mean temperature of the previous month. Mycelium biomass of L. deliciosus was positively correlated with relative humidity and negatively correlated with mean temperature and radiation. No significant correlation between productivity of the plots with the soil mycelium biomass was observed for any of the two species. No correlations were found between B. edulis sporocarp production and weather parameters. Sporocarp production of L. deliciosus was positively correlated with precipitation and relative humidity and negatively correlated with maximum and minimum temperatures. Both species have similar distribution over time, presenting an annual dynamics characterized by a seasonal variability, with a clear increase on the amounts of biomass during the coldest months of the year. Soil mycelial dynamics of both species are strongly dependent on the weather.

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

“…The amount of L. deliciosus extraradical mycelium detected in our soil samples is in agreement with the results of De la Varga et al (2013) in Central Spain. They report around 1.5 (CI 95 : À1.3 to 4.3) mg of mycelium g À1 dry sieved soil in November 2010, which is within our CI 95 of 1.4-9.8 in the undisturbed plots.…”

“…The abundance of T. melanosporum soil mycelium was found to be positively correlated with early onset of truffle production in Quercus ilex stands (Suz et al, 2008), while in a study in mature Pinus sylvestris stands, the quantity of Boletus edulis soil mycelium was correlated with the number of ectomycorrhizae (De la Varga et al, 2012), but not with sporocarp production of either B. edulis or L. deliciosus (De la Varga et al, 2013). Yet, Parladé et al (2007) did find a correlation between L. deliciosus extraradical mycelium and mycorrhizae at the end of a short-term greenhouse inoculation study.…”

“…Species-specific primers have been developed for the identification of L. deliciosus and allow the detection and quantification of this fungus in the soil (De la Varga et al, 2013;Hortal et al, 2006). With these tools, we can address the use of L. deliciosus extraradical mycelium abundance as a response variable for silviculture interventions at forest stand level, as well as researching its relationship with sporocarp productions observed in pine forests (Bonet et al, 2012).…”

Influence of Climate and Economic Variables on the Aggregated Supply of a Wild Edible Fungi (Lactarius deliciosus)

“…The literature presents cases in which this hypothesis is confirmed [26], but in the particular case of the saffron milk cap, some studies done in Spain do not show any significant relationship between the yield of this mushroom and temperature [39], except that the arrival of the winter frosts limits their yield [50]. Other authors have found correlations among mushroom yields and temperatures, although the sign of the correlations, whether positive [51] or negative [52], is not clear. It seems that a definitive conclusion in the literature regarding the influence of temperature on the yield of edible wild mushrooms does not exist.…”

Mushroom Emergence Detected by Combining Spore Trapping with Molecular Techniques

“…In this context, new techniques that do not require the collection of mushrooms can improve the estimation of mushroom yields. Except for a few cases (7), no correlations have been found between the belowground mycelial biomass of specific species and their mushroom production (8)(9)(10), even though positive correlations have been found between root mycorrhizal colonization and soil mycelia (11). In this regard, new monitoring approaches using fungal spores, such as spore trapping, may represent a new way of addressing this challenge.…”