A phylogenetic redefinition of anamorph genera in Mycosphaerella based on ITS rDNA sequence and morphology

Anamorph genera associated with Mycosphaerella are separated on a combinati on of characters such as conidiomatal structure, the nature and arrangement of conidiophores, conidiogenesis, dehiscence scars and pigmentation. To da te 27 genera have been reported as anamorphs of Mycosphaerella, 19 of which were included in this study. Based on the phylogeny of the ITS1, 5.8S, and ITS2 rDNA sequence data, Mycosphaerella proved to be monophyletic. The maj or group consisted of several small clusters correlating to specific anamor ph genera, as well as other clusters containing an assemblage of anamorph g enera. Although Mycosphaerella is monophyletic, it appears that many of the morphological characters defining different anamorph genera evolved more t han once and for the most part do not represent true groups within Mycospha erella. Nevertheless, the anamorph generic concepts contain valuable inform ation of practical use to plant pathologists and mycologists working with t hese organisms. Based on these results, as well as a re-evaluation of the c riteria upon which anamorph genera are distinguished in this complex, a red uced set of informative criteria and genera are proposed. The degree of sca r thickening, darkening and refraction, as well as the presence or absence of pigmentation in conidiophores and conidia still appear to be useful feat ures delimiting anamorph genera of Mycosphaerella.