title: Novel fungi from an ancient niche: cercosporoid and related sexual morphs on ferns.
abstract: The fern flora of the world (Pteridophyta) has direct evolutionary links with the earliest vascular plants that appeared in the late Devonian. Knowing the mycobiota associated to this group of plants is critical for a full understanding of the Fungi. Nevertheless, perhaps because of the minor economic significance of ferns, this niche remains relatively neglected by mycologists. Cercosporoid fungi represent a large assemblage of fungi belonging to theMycosphaerellaceaeandTeratosphaeriaceae(Ascomycota) having cercospora-like asexual morphs. They are well-known pathogens of many important crops, occurring on a wide host range. Here, the results of a taxonomic study of cercosporoid fungi collected on ferns in Brazil are presented. Specimens were obtained from most Brazilian regions and collected over a 7-yr period (2009-2015). Forty-three isolates of cercosporoid and mycosphaerella-like species, collected from 18 host species, representing 201 localities, were studied. This resulted in a total of 21 frond-spotting taxa, which were identified based on morphology, ecology and sequence data of five genomic loci (actin, calmodulin, ITS, LSU and partial translation elongation factor 1-α). One novel genus (Clypeosphaerella) and 15 novel species (Cercospora samambaiae,Clypeosphaerella sticheri,Neoceratosperma alsophilae,N. cyatheae,Paramycosphaerella blechni,Pa. cyatheae,Pa. dicranopteridis-flexuosae,Pa. sticheri,Phaeophleospora pteridivora,Pseudocercospora brackenicola,Ps. paranaensis,Ps. serpocaulonicola,Ps. trichogena,Xenomycosphaerella diplaziiandZasmidium cyatheae) are introduced. Furthermore, 11 new combinations (Clypeosphaerella quasiparkii,Neoceratosperma yunnanensis,Paramycosphaerella aerohyalinosporum,Pa. dicranopteridis,Pa. gleicheniae,Pa. irregularis,Pa. madeirensis,Pa. nabiacense,Pa. parkii,Pa. pseudomarksiiandPa. vietnamensis) are proposed.Finally, nine new host associations are recorded for the following known fungal species:Cercospora coniogrammes,Cercosporasp. Q,Ps. abacopteridicola,Ps. lygodiicolaandPs. thelypteridis.
authors.affiliation: Departamento de Fitopatologia, Universidade Federal de Viçosa, CEP: 36.570-900, Viçosa, Minas Gerais, Brazil.
authors.forename: E
authors.initials: E
authors.lastname: Guatimosim
authors.affiliation: Departamento de Biologia Vegetal, Universidade Federal de Viçosa, CEP: 36.570-900, Viçosa, Minas Gerais, Brazil.
authors.forename: P B
authors.initials: PB
authors.lastname: Schwartsburd
authors.affiliation: Departamento de Fitopatologia, Universidade Federal de Viçosa, CEP: 36.570-900, Viçosa, Minas Gerais, Brazil.
authors.forename: R W
authors.initials: RW
authors.lastname: Barreto
authors.affiliation: CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands.; Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa.; Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: P W
authors.initials: PW
authors.lastname: Crous
keywords: Cercospora; Mycosphaerella; Pteridophyta; biodiversity; frond spot; multilocus sequence typing (MLST); phylogeny; systematics