Exobasidium vaccinii disease symptoms. Image taken from www.eol.org

Exobasidium vaccinii haploid sporidia, growing in liquid culture as they were used for isolation of DNA and RNA. A) DIC image B) DAPI stain. Scale bars: 5 micrometer. Images by Gunther Doehlemann

Exobasidium vaccinii is a basidiomycete that belongs to the subphylum of Ustilaginomycota, class of Exobasidiomycetes. Exobasidiomycetes are holobasidiate and dimorphic, but they do not form teliospores in the parasitic phase. E. vacinii is an endoparasitic pathogen of cowberry (Vaccinium vitis-idaea). Typical symptoms caused by E. vaccinii are bright red-colored leaves (See image) and finally the formation of massive galls, which are covered by fungal mycelium. Galls are typically formed at the lower leaf side.