Piedraia hortae Fonseca & Leão, Memórias do Instituto Oswaldo Cruz, Supplemento 4(Suppl.): 124 (1928)
Index Fungorum number: IF 267365; Facesoffungi number: FoF xxx, Fig. 1
Description: see Hyde et al. (2013).
Material examined: see Hyde et al. (2013).
Fig. 1. Alanphillipsia aloes (CBS H-21418, holotype redrawn from Crous et al. 2013) a−d Conidiogenous cells, paraphyses, macro- and microconidia. Scale bars: a−d = 10 µm.
Importance and role
Importance of genus to ecosystem
Species of Piedraia are dermatophytes which cause fungal infection known as ‘black piedra’. Piedraia infects hair on the scalp, beard and other pubic hairs (Figueras and Guarro 1997). The natural habitat of Piedraia is hair which is composed primarily of keratin (Savill 1952). Based on previous studies, it has been demonstrated that Piedraia can use keratin as its sole source of nutrients (Jones 1976).
Industrial relevance and applications
Piedraia are cultivated for cosmetic use. The nodules of black piedra are considered as attractive and are used to darken the hair especially of albino people in some tribes (Moyer et al. 1964).
Piedraia is pathogenic to human and cause fungal infection of the hair shafts. The disease is also known as Trichomycosis nodosa (Sharma et al. 2020). No biocontrol agent has yet been reported from Piedraia.
Biochemical importance of the genus, chemical diversity or applications
Piedraia forms a variety of crystals in cultures in which high concentration of calcium ions were detected. This explains the hard and crusty nature of the fungus (Jones 1976).
Diversity of the genus
Piedraia comprises two species. P. hortae was isolated from hair of dead homo sapiens in Brazil while P. quintanilhae was found from hair of Genetta tigrina (Viverridae) in Angola.