Phylogenetic reassessment of Mycosphaerella spp. and their anamorphs occurring on Eucalyptus

Species of Eucalyptus, mostly native to Australia, are widely planted as exotics in the tropics and Southern Hemisphere. These plantations represent an important source of fuel-wood, structural timber and pulp. Eucalyptus plantations are, however, vulnerable to infection by pathogens, including Mycosphaerella spp. and their anamorphs, which have caused substantial damage, in many parts of the world. More than 30 species of Mycosphaerella, and close to 30 anamorph species for which the Mycosphaerella state remains unknown, are associated with leaf and shoot disease on Eucalyptus spp., worldwide. Although several studies using DNA sequence data have been applied to resolve the phylogenetic relationships between Mycosphaerella spp. on Eucalyptus, the number of species treated has been incomplete. In the present study, isolates of 44 Mycosphaerella species or their anamorphs associated with lesions on Eucalyptus leaves were compared based on DNA sequence data for the internal transcribed spacer region (ITS1 & ITS2) and the 5.8S gene. In addition, DNA sequence data from the elongation factor 1and the -tubulin gene regions were used to resolve species in the M. nubilosa species complex. As a result of these comparisons, 11 new species are described. Mycosphaerella juvenis is reduced to synonymy with M. nubilosa and an epitype specimen and ex-epitype culture are designated for the latter. Mycosphaerella nubilosa is recorded as a serious agent of Mycosphaerella leaf blotch on E. globulus in Spain. This is also the first definitive record of this pathogen occurring on Eucalyptus in Europe. Taxonomic novelties: Mycosphaerella madeirae Crous & Denman sp. nov., M. toledana Crous & G. Bills sp. nov. (anamorph Phaeophleospora toledana Crous & G. Bills sp. nov.), M. readeriellophora Crous & J.P. Mansilla sp. nov. (anamorph Readeriella readeriellophora Crous & J.P. Mansilla sp. nov.), M. communis Crous & J.P. Mansilla sp. nov. (anamorph Dissoconium commune Crous & J.P. Mansilla sp. nov.), M. ohnowa Crous & M.J. Wingf. sp. nov., Passalora zambiae Crous & T. Coutinho sp. nov., Pseudocercospora pseudoeucalyptorum Crous sp. nov., Readeriella novaezelandiae Crous sp. nov.