Molecular and morphological differentiation of Botryosphaeria dothidea (anamorph Fusicoccum aesculi) from some other fungi with Fusicoccum anamorphs

Differentiation of Botryosphaeria species with Fusicoccum anamorphs has dep ended on recognition of the anamorphs. This has resulted in some confusion in the taxonomy and our understanding of the pathology of these species bec ause these anamorphs are very similar morphologically and the characters us ed for differentiation can be influenced by the substrate. We have examined 89 isolates identified by the collectors as B. dothidea. (F. aesculi), B. ribis (Fusicoccum sp.), B. parva (F. parvum), or F. luteum. Cluster analysi s of random amplified polymorphic DNA (RAPD) marker data identified three d istinct groups, which we have designated Bd (probable B. dothidea), Br (pro bable B. ribis, but including isolates of B. parva), and Fl (probable F. lu teum). Analysis of DNA sequence of the nuclear rDNA ITS region from a subse t of isolates from each group supports these relationships. Measurement of conidia from a subset of isolates revealed statistically significant differ ences in shape that can be used to differentiate between conidia of the Bd group isolates and these of the other groups. Conidia of the Br and Fl grou p isolates, however were similar. We conclude that B. dothidea can be diffe rentiated from these other fungi with Fusicoccum anamorphs by all three tec hniques.