Phylogenetic and morphological re-evaluation of Antherospora on Barnardia japonica collected in Japan

Abstract

Abstract Antherospora vaillantii is an anther smut fungus that was originally considered occurring on Muscari spp. around the world; however, cryptic species were revealed during recent taxonomic investigations, thus emphasizing the importance of host specificity. In Japan, A. vaillantii was identified on Barnardia japonica in 1936. Although the recent revelations indicate that it may be part of a complex based on the host plant genus, the phylogenetic placement of this Japanese species is currently unresolved. In this investigation, seven specimens of the A. vaillantii complex were collected from the Kanto area of Japan, and six new single teliospore isolates were established. Molecular phylogenetic analyses based on the internal transcribed spacer sequences and large subunit nuclear ribosomal DNA (28S) region indicated that the new samples formed a monophyletic clade with other Antherospora spp. among Floromycetaceae lineage. Our samples were separated from other known species of Antherospora and formed a robust monophyletic clade in any analysis. Detailed morphological observations revealed that the new samples could be distinguished from other known Antherospora species. As a result, it is proposed that A. barnardiae can accommodate B. japonica parasites. The evolutionary processes of Floromycetaceae in relation to their Asparagaceous host plants have also been carefully discussed. Based on the morphological observations of the basidiospore ontogenic patterns, the familial concept of Floromycetaceae was redefined.