Phylogenetic study of Botryosphaeria species and associated anamorphic fungi and their evolutionary relationships with other ascomycetes

The genus Botryosphaeria and many of the species comprising it are not well-defined. The goals of this research were to improve the understanding of species definition within Botryosphaeria, to resolve the relationships among different Botryosphaeria species, and to clarify their relationships with other filamentous ascomycetes. The specific objectives were to: (i) determine whether Botryosphaeria species and associated anamorphic fungi belong to a monophyletic group; (ii) determine whether form-genera of anamorphic fungi associated with Botryosphaeria species indicate close relationships among their members; (iii) infer phylogenetic relationships among Botryosphaeria species and associated anamorphic fungi; (iv) determine whether the specialization either on angiosperms or on gymnosperms contributed to the speciation of Botryosphaeriaspecies; (v) determine whether two types of Sphaeropsis sapinea and S. sapinea f. sp. cupressi are conspecific; (vi) determine whether B. dothidea and B. ribis are conspecific; and (vii) infer phylogenetic relationships of Botryosphaeria species with Guignardia species and other ascomycetes.;Phylogenetic analyses (including distance, parsimony, and maximum likelihood methods) of the ITS and 5.8s rDNA, mt SSU rDNA, and 18s rDNA sequences, cluster and principal coordinate analyses of the ISSR fingerprints, and cluster analysis of isozyme data from Botryosphaeria species and associated anamorphic fungi were performed in order to approach these objectives. Results indicate that the genus Botryosphaeria is not monophyletic, with B. vaccinii and Phyllosticta vaccinii not closely related to other fungi comprising this genus; within the main group of Botryosphaeria species and related anamorphic fungi, there is a division between the light-colored and narrow conidial subgroup and the dark-colored and broader conidial subgroup; B. ribis and B. dothidea are distinct; S. sapinea f. sp. cupressi is distinct from A and B RAPD marker groups of Sphaeropsis sapinea; form genera Sphaeropsis and Diplodia are not indicative of close relationships among different species within each genus; the specialization either on gymnosperms or on angiosperms is not indicative of close relationships among these fungi; Botryosphaeria and Guignardia are closely related; and the current placement of Botryosphaeria in Pleosporales of Loculoascomycetes was not supported. This study has established a foundation for future taxonomic and pathological research of Botryosphaeria species and related fungi.