Combined multiple gene genealogies and phenotypic characters differentiate several species previously identified as Botryosphaeria dothidea

Abstract

Botryosphaeria dothidea is one of the most commonly reported species in a genus of important pathogens of woody plants. This taxon generally is accepted to represent a species complex, and hence its identity remains unclear. Previous studies either have treated B. dothidea as the valid name for B. ribis and B. berengeriana or argued for them to be separate entities. To add to the confusion, no ex-type cultures are available for either B. dothidea or B. ribis. The aim of the present study, therefore, was to recollect and characterize these fungi and designate a set of reference cultures that can be used in future studies. To this end, morphological, cultural and multi-allelic DNA sequence datasets from the rDNA (ITS 1, 5.8S, and ITS 2), β-tubulin and EF1-α genes were used to fully characterize these species. Botryosphaeria dothidea was found to be distinct from B. ribis, while B. berengeriana was retained as synonym of the former name. Furthermore, Fusicoccum aesculi is accepted as anamorph of B. dothidea, while the anamorph of B. ribis is newly described as F. ribis sp. nov. Botryosphaeria ribis could be distinguished from B. parva based on β-tubulin and EF1-α sequence data. A combined phylogeny of the three gene regions used in this study also showed that the genus Botryosphaeria represents two distinct phylogenetic assemblages that correspond to species with Diplodia and Fusicoccum anamorphs.

• Botryosphaeria
• epitypification
• Fusicoccum
• key
• phylogeny
• systematics

We thank the National Research Foundation, Mellon Foundation, members of the Tree Pathology Co-operative Programme (TPCP) and the THRIP initiative of the Department of Trade and Industry (DTI), South Africa, for financial assistance. We also are most grateful to Prof. George Hudler, Dr. Orlando Petrini, Dr. Liliane Petrini, Ms. Neria Römer, Ms. Cristina Stinelli and Mr. Pierfranco Arrigoni for their tremendous effort in assisting us in collecting epitype and other specimens crucial to this study. Likewise, this study would not have been possible without the support of culture collections and herbaria worldwide (CUP, PDD, RO, S) that kindly supplied specimens and cultures.