Metabarcoding of fungal communities reveals high diversity and strong altitudinal turnover in the Argentinian Yungas forests

JÓZSEF GEML; NICOLÁS PASTOR; LISANDRO FERNANDEZ; SILVIA PACHECO; EDUARDO R. NOUHRA

Medellin

Congreso; VIII Congreso Latinoamericano de Micología; 2014

Asociación Latinoamericana de Micología

The Yungas, a system of tropical and subtropical montane forests on the eastern slopes of the Andes, are extremely diverse and severely threatened by anthropogenic pressure and climate change. Previous mycological works focused on macrofungi (e.g., agarics, polypores) and mycorrhizae in Alnus acuminata forests, while fungal diversity in other parts of the Yungas has remained mostly unexplored. We carried out DNA metabarcoding of soil samples taken at 24 sites along the entire latitudinal extent of the Yungas in Argentina using Ion Torrent sequencing of ITS2 rDNA. The sampled sites represent the three altitudinal forest types: the piedmont (400?700 masl), montane (700?1500 masl), and montane cloud (1500?3000 masl) forests. The deep sequence data presented here (i.e. 4 108 126 quality-filtered sequences) indicate very high fungal richness and strong community turnover among the three altitudinal zones. Of the 14 039 fungal OTUs, Ascomycota was by far the dominant phylum (6355 OTUs, 45.27%), followed by Basidiomycota with (3511, 25.01%), basal lineages formerly classified in Zygomycota (723, 5.15%), Glomeromycota (409, 2.91%), and Chytridiomycota (67, 0.48%). In addition, there were 2974 (21.18%) unidentified fungal OTUs with most similar sequences to other environmental sequences without assignment to a phylum. The three most diverse taxonomic orders were Agaricales (1627, 11.59%), Hypocreales (1255, 8.94%), and Mortierellales (613, 4.37%). Fungal community composition correlated strongly with elevation, with many fungi showing preference for a certain altitudinal forest type. For example, ectomycorrhizal and root endophytic fungi were most diverse in the montane cloud forests, while the diversity values of various saprobic groups were highest at lower elevations. Despite the strong altitudinal community turnover, fungal diversity was comparable across the different zonal forest types. Besides elevation, soil pH, N, P, and organic matter contents correlated with fungal community structure as well, although most of these variables were co-correlated with elevation. Our data provide an unprecedented insight into the high diversity and spatial distribution of fungi in the Yungas forests and demonstrate the immense potential of DNA metabarcoding to augment our current knowledge of fungal diversity and to better understand environmental factors that influence fungal community structure.