Taxonomy and ecology of epifoliar fungi

Epifoliar fungi are poorly studied symbionts that co-inhabit the surface of living plants. They are relatively understudied and generally lack molecular data thus there is considerable taxonomic confusion in the group as early taxonomic studies were based on morphology. Many taxa are difficult to isolate for obtaining cultures and therefore molecular analysis is a limitation for biotrophic species unless sequenced directly from the fruiting bodies. Epifoliar fungi evolved from diverse ancestors and include mainly members of the Dothideomycetes, Eurotiomycetes, Lecanoromycetes, and Sordariomycetes. The classification of epifoliar fungi is challenging due to taxonomic confusion in historical classifications and insufficient molecular data. In this study, we provide a summary of major epifoliar families (Asterinaceae, Meliolaceae, Micropeltidaceae, Microthyriaceae, Parmulariaceae and Zeloasperisporiaceae). The modes of nutrition of each family are also reviewed. Character analysis of a combined LSU, SSU and rpb2 dataset shows that epifoliar fungi have different taxonomic and evolutionary relationships in Ascomycota. Epifoliar fungi are generally considered to be host-specific, but this needs to be confirmed using molecular data as morphological differences are minor. Therefore, future research should focus on addressing the drawbacks of current studies and use new molecular approaches. To obtain better insights into epifoliar fungi, a combination of taxonomic and ecological studies is needed.