Fungal community in chestnut orchards with different Hypholoma fasciculare aboveground abundance: potential implications for sustainable production

Abstract

European chestnut (Castanea sativa Mill.) trees have a significant impact in the Portuguese economy, due to the production of chestnuts and wood, and other related activities, such as mushroom collection and hunt. Hypholoma fasciculare (Huds.) is a saprophytic fungus widely distributed in Trás-os-Montes (northeast of Portugal) chestnut groves that displays an in vitro strong antagonistic activity against ectomycorrhizal (EMC) fungi. In this study, the above- and belowground fungal diversity was evaluated in three chestnut orchards, containing distinct H. fasciculare sporocarps abundances in an attempt to better understand the potential of this fungus to attain an improved chestnut tree sustainable productivity. Aboveground analysis was performed based on macrofungi collection during fruiting seasons (spring and autumn) of two consecutive years. Belowground evaluation was based on the metabarcoding of chestnut orchards soil DNA, using the fungal barcode ITS1 and a high-throughput sequencing (454-sequencing) approach. Although all collected fruitbodies were identified as being produced by Basidiomycota fungi, a more diversified fungal community was revealed by the belowground approach. Both approaches have revealed a rich and abundant ECM community in all chestnut orchards. The correlation between the abundance of H. fasciculare fruitbodies and specific fungal guilds fruitbodies/reads suggests that this fungus may affect soil fungal community, mainly ECM and phytoparasites, as well as species composition of fungal communities. Although not conclusive, the results suggest that H. fasciculare presence could be critical for sustainable chestnut ecosystems.