[BBG03-P03] High diversity and spatio-temporal variations in fungal spore communities
Keywords:Propagules, Ectomycorrhizal, DNA barcoding, Saprotroph, molecular identification, dispersion
In this study, we used simple spore traps placed in forest plots to sample fungal spores weekly, simultaneously to fungal fruiting body samplings during the autumn season. Trapped spore samples were quantified by qPCR and analyzed by metabarcoding of the ITS2 region to study the fungal community composition. We also quantified the spores from a target edible fungal species, Lactarius vinosus, by qPCR using a specific hydrolysis probe. Our aim was to describe the spatio-temporal dynamics of the deposited spore community, to understand how rainfall events may affect spore deposition and to study whether trapped fungal spores reflect the fruiting body community.
Our results showed that spore community is hyperdiverse. We detected 12 different fungal functional guilds, with mycorrhizal and plant pathogens being the most diverse. Spore community composition changed considerably over time due to the emergence of ephemeral fruiting bodies and rapid spore deposition (lasting from one to two weeks). Community compositional changes across sampling weeks were higher than across sampling plots. Average number of spores recorded each week was 7.1 M spores × plot-1 × week-1, with a peak of almost 60 M spores during an extreme rainfall event. Although spore deposition in traps also occurred in absence of rainfall events, both fungal diversity and fungal spore abundances were positively correlated with precipitation events. Especially high was the correlation between rainfall and spore abundances of soil saprotrophs, represented mostly by puffballs (e.g. Bovista, Lycoperdon). The spores of 37 fungal species that produced fruiting bodies in the study plots were identified. For many species, the emergence of epigeous fruiting bodies was followed by a peak in the relative abundance of their airborne spores. There was significant positive correlation between fruiting body yields and spore abundance in time for five out of seven fungal species. There was no relationship between fruiting body yields and their spore abundance at plot level, indicating that some of the spores captured in each plot were arriving from the surrounding areas.
Our results provide new insights on the large functional diversity associated to spore deposition and shows that this deposition may be driven by rainfall events. This approach could also help in identifying the hidden diversity of the airborne fungal spores circulating in the atmosphere. Further research could help to identify the spore deposition patterns for most common fungal species.