Tuberculina: rust relatives attack rusts.

Molecular sequence data together with ultrastructural features were used to infer the phylogenetic position of Tuberculina species. Additional ultrastructural characteristics were used to determine their mode of nutrition. We investigated ultrastructural morphology of the type species Tuberculina persicina and determined base sequences from the D1/ D2 region of the nuclear large-subunit ribosomal DNA of the three commonly distinguished Tuberculina species, T. maxima, T. persicina and T. sbrozzii. Analyses of sequence data by means of a Bayesian method of phylogenetic inference using a Markov Chain Monte Carlo technique reveal the basidiomycetous nature of Tuberculina. Within the Urediniomycetes, Tuberculina clusters as a sister group of Helicobasidium, closely related to the rusts (Uredinales). This phylogenetic position is supported by the uredinalean architecture of septal pores in Tuberculina. In addition, we present aspects of the ultrastructural morphology of the cellular interaction of Tuberculina and rusts showing a unique interaction with large fusion pores, revealing the mycoparasitic nature of Tuberculina on its close relatives, the rusts.