New Canadian lineages of ergot fungi revealed by multi-gene phylogeny

Claviceps purpurea, the type species of the genus, was first described by Tulasne 1853 based on a specimen from rye. Other cereal crops (i.e. Triticum and Avena) and grasses (Alopercuri, Dactylis, Lolium, and Poa) were noted as additional hosts. To date, the reported host range has increased to more than 400 species in at least 19 genera belonging to 3 subfamilies of grasses (Poaceae). Unlike other Claviceps spp. that infect only a few genera in the same tribe, C. purpurea is unique in having a wide host range, leading to suspicion that it might be a complex of multiple species. Studies have confirmed cryptic speciation correlated with ecological niches. The taxonomy of Claviceps species occurring in Canada has been little explored. Among 600 specimens of Claviceps in the National Mycology Herbarium (DAOM), 80% are labeled as C. purpurea. To better understand species composition and genetic diversity of ergot fungi in Canada, we conducted multi-gene phylogenetic studies using recently collected samples from different parts of the country, along with historical specimens housed in DAOM. The loci sequenced include rDNA ITS, house-keeping genes (EF1-alpha, BT and RPB2) and ergot alkaloid synthesis genes (easE, cloA). Based on individual locus and concatenated alignments, the analyses recognized six lineages within the C. pupurea complex, among which three appear to be new. Morphological and phenotypic studies were undertaken to characterize these lineages.