Ascospore morphology of bryophilous Pezizales is closely associated with the place of infection and host ecology

Abstract

Fungal spores are morphologically highly diverse and are therefore frequently used as diagnostic characters in taxonomy. However, the connection between spore morphology and fungal ecology remains poorly understood. Using phylogenetic comparative analyses, we investigated the putative relationships between four ascospore traits and the dominant place of infection, host ecology, and host taxonomic placement in 123 species of biotrophic parasites of bryophytes. Ascospore shape, ornamentation height and relative lipid content are significantly correlated in bryophilous Pezizales. Species attached by their hyphae to bryophyte rhizoids have more globose ascospores with higher ornamentation and relative lipid content than species attached to aboveground organs. Furthermore, some ascospore traits are significantly associated with host lifespan, habitat preferences, and taxonomic placement of their host bryophytes. Our results suggest that the ascospore morphology in this fungal group is closely linked to its ecology and several of the detected relationships point to the existence of distinct dispersal strategies. • Multiple ascospore traits are significantly correlated in bryophilous Pezizales • Ascospore morphology is closely associated with characteristics of host bryophytes • Diverse ascospores in this group likely reflect differences in dispersal strategies • Requirements for longer survival could play a crucial role in ascospore evolution