Phylogenetic study of clavicipitaceous fungi using acetaldehyde dehydrogenase gene sequences

Aciculosporium and Heteroepichloë (Clavicipitaceae) are characteristic bambusicolous fungi in east Asia. In this study, we examined their intergeneric relationships based on the ALDH1-1 gene, which encodes a member of the aldehyde dehydrogenase family. In the clavicipitaceous fungi examined in this study, the nucleotide sequence of the third exon of ALDH1-1 (Exon-3) is 889 bp in length and has no insertion/deletion. A phylogenetic tree based on Exon-3 indicated that the clavicipitaceous fungi could be divided into two large groups: Cordyceps, Nomuraea, and Ustilaginoidea species formed a paraphyletic group, and the other grass biotrophic species formed a monophyletic group. This monophyletic group was further divided into three groups with high bootstrap support: i.e., species with Neotyphodium anamorphs (e.g., Epichloë), species with Ephelis anamorphs (e.g., Heteroepichloë), and Aciculosporium– Claviceps species. We discuss the relationships among Aciculosporium, Heteroepichloë, and other clavicipitaceous fungi.