Ultrastructural observations on the ascomata and ascospores of the truffle Mattirolomyces terfezioides

Abstract

The septal pore ultrastructure of non-ascogenous and reproductive hyphae, as well as development of the spore wall were examined in the truffle Mattirolomyces terfezioides (Mattir.) E. Fisch. (Ascomycota, Pezizales, Pezizaceae) and compared with other pezizalean taxa. The septal pore in ascogenous hyphae of M. terfezioides is a uni- or bi-convex band of the type found in the Pezizaceae. Septal pore ultrastructure in other hyphae included a uniconvex band with lamellate structure. Woronin bodies were globose to hexagonal, and infrequently ellipsoid in shape. Hexagonal Woronin bodies have not been previously reported in the Pezizaceae. Ascospore delimitation starts with two delimiting membranes and the spore-wall development is typical of the Pezizales. The heterogeneously staining spines of the secondary cell wall differ from the structures of Terfezia species. The ultrastructural characteristics of M. terfezioides show the general characteristics of the Pezizaceae, except that the hexagonal Woronin body form is new to this family. The spore delimitation, spine-cap structure, and Woronin body shape of M. terfezioides presented here are in agreement with molecular taxonomic results, which separate the genus from Terfezia and call into question the generic position of Mattirolomyces tiffanyae Healy.