Rainfall homogenizes while fruiting increases diversity of spore deposition in Mediterranean conditions

Abstract

There is a lack of knowledge regarding the main factors modulating fungal spore deposition in forest ecosystems. We have described the local spatio-temporal dynamics of fungal spore deposition along a single fruiting season and its relation with fruit body emergence and rainfall events. Passive spore traps were weekly sampled during autumn and analysed by metabarcoding of the ITS2 region in combination with qPCR. There were larger compositional changes of deposited spores across sampling weeks than amongst sampling plots. Spore diversity and abundance correlated with mushroom emergence and weekly rainfall. Spore compositional changes were related to rainfall, with lower spatial compositional heterogeneity across plots during weeks with higher rainfall. Soil saprotrophs, and amongst them, puffball species, showed the strongest positive correlation with rainfall across fungal guilds. We saw high fine-scale temporal changes of deposited spores, and both mushroom emergence and rainfall may be important factors driving airborne spore deposition.

This work was partially supported by the Spanish Ministry of Science, Innovation and Universities, grants N° AGL2015-66001-C3, RTI2018-099315-A-I00, the CERCA Programme / Generalitat de Catalunya, and by the European project StarTree (No. 311919). J.G.A. was supported by Juan de la Cierva (Grant number IJCI-2014-21393) and Ramon y Cajal fellowships (RYC-2016-20528), while JO was supported by Ramon y Cajal fellowship (RYC-2015-17459). José Antonio Bonet benefitted from a Serra-Húnter Fellowship provided by the Generalitat of Catalunya. Carles Castaño received the support of the Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya through the program of Doctorats Industrials, and benefitted from a STSM grant from COST Action FP1203.