Dismantling a complex of anther smuts (Microbotryum) on carnivorous plants in the genus Pinguicula

The anther smuts of the genus Microbotryum are known from host plant species belonging to the Caryophyllaceae, Dipsacaceae, Lamiaceae, Lentibulariaceae, Montiaceae, and Primulaceae. Of these, the anther smuts on Caryophyllaceae, in particular on Silene spp., are best known because they include model organisms studied in many disciplines of fungal biology. For Microbotryum species parasitic on Caryophyllaceae, a high degree of host specificity was revealed and several cryptic species were described. In contrast, the host specificity within Microbotryum pinguiculae occurring in anthers of different Pinguicula species (Lentibulariaceae) has not been investigated in detail until now. The anther smuts on Pinguicula alpina, P. villosa, and P. vulgaris, on which M. pinguiculae was described, were analyzed using nuc rDNA ITS1-5.8S-ITS2 and nuc rDNA 28S D1-D2 sequences and morphology to determine if they belong to one polyphagous species or rather represent three host-specific species. The results of the morphological investigations revealed no decisive differences between the anther smuts on different Pinguicula species. However, genetic divergence and molecular phylogenetic analyses, which split the specimens according to host plant species, supported host specificity of the anther smuts on different Pinguicula species. Accordingly, in addition to Microbotryum pinguiculae s. str. on Pinguicula vulgaris, M. alpinum sp. nov. on P. alpina from Europe and M. liroi sp. nov. on P. villosa from Asia are described and illustrated.