Five new Pseudophialophora species from grass roots in the oligotrophic pine barrens ecosystem

•Five new Pseudophialophora species were uncovered from grass roots in pine barrens.•Pseudophialophora belongs to Magnaporthaceae based on multi-locus phylogeny.•Several Pseudophialophora species showed negative effects on growth of switchgrass.

During our recent survey of fungi in the oligotrophic pine barrens ecosystem, five new Pseudophialophora species, Pseudophialophora angusta, P. dichanthii, P. magnispora, P. tarda, and P. whartonensis, were uncovered from the roots of switchgrass (Panicum virgatum) and tapered rosette grass (Dichanthelium acuminatum). The five new fungal species are described based on morphological characteristics and DNA sequences of SSU, ITS, LSU, MCM7, RPB1, and TEF1 genes. The 6-locus phylogeny indicates that Pseudophialophora species form a monophyletic clade in Magnaporthaceae of Magnaporthales. A key for all described species in Pseudophialophora is provided, including these five and three previously published species. Distinctions among the new species and other related species are discussed. The plant–fungal interaction experiment indicates that P. angusta, Pseudophialophora eragrostis, P. magnispora, Pseudophialophora schzachyrii, P. tarda, and P. whartonensis have negative effects on the growth of switchgrass. Runner hyphae were observed from the inoculated switchgrass roots, which are typical structures of root-infecting pathogens.