Characterization of Cercospora flagellaris sensu stricto on its Original Host, Phytolacca americana, Based on Korean Collections

Cercospora cf. flagellaris is one of the unresolved species complexes within the genus Cercospora. Despite recent advances in molecular approaches for species delimitation using multigene sequence analysis, the identity of C. flagellaris remains unclear. As new records are accumulated, the complexity of this species group increases, encompassing hosts from a wide range of plant families. Phytolacca americana, a species native to North America and later introduced to East Asia, was the original host of this fungus. Since 1991, leaf spot diseases caused by C. flagellaris have been consistently reported in Korea. In this study, we summarized all isolates identified as C. flagellaris from P. americana in Korea to date, to infer their morphological and molecular phylogenetic identities and to understand the true identity of this fungus. All isolates were morphologically and molecularly examined, illustrated, and their phylogenetic placement was demonstrated in a tree inferred from multigene sequence analyses.