Citizen science project reveals novel fusarioid fungi (Nectriaceae, Sordariomycetes) from urban soils

Soil fungi play a crucial role in soil quality and fertility in being able to break down organic matter but are frequently also observed to play a role as important plant pathogens. As part of a Citizen Science Project initiated by the Westerdijk Fungal Biodiversity Institute and the Utrecht University Museum, which aimed to describe novel fungal species from Dutch garden soil, the diversity of fusarioid fungi (Fusarium and other fusarioid genera), which are members of Nectriaceae (Hypocreales) was investigated. Preliminary analyses of ITS and LSU sequences from more than 4 750 isolates obtained indicated that 109 strains belong to this generic complex. Based on multi-locus phylogenies of combinations of cmdA, tef1, rpb1, rpb2 and tub2 alignments, and morphological characteristics, 25 species were identified, namely 22 in Fusarium and three in Neocosmospora. Furthermore, two species were described as new namely F. vanleeuwenii from the Fusarium oxysporum species complex (FOSC), and F. wereldwijsianum from the Fusarium incarnatum-equiseti species complex (FIESC). Other species encountered in this study include in the FOSC: F. curvatum, F. nirenbergiae, F. oxysporum and three undescribed Fusarium spp.; in the FIESC: F. clavus, F. croceum, F. equiseti, F. flagelliforme and F. toxicum; Fusarium tricinctum species complex: F. flocciferum and F. torulosum; the Fusarium sambucinum species complex: F. culmorum and F. graminearum; the Fusarium redolens species complex: F. redolens; and the Fusarium fujikuroi species complex: F. verticillioides. Three species of Neocosmospora were encountered, namely N. solani, N. stercicola and N. tonkinensis. Although soil fungal diversity has been well studied in the Netherlands, this study revealed two new species, and eight new records: F. clavus, F. croceum, F. flagelliforme, F. odoratissimum, F. tardicrescens, F. toxicum, F. triseptatum and N. stercicola.