A novel species of Botrytis isolated from peony in Alaska, USA, and grape in Trento District, Italy, was identified based on morphology, pathogenicity, and sequence data. The grape and peony isolates share sequence homology in the glyceraldehyde-3-phosphate dehydrogenase (G3PDH), heat shock protein 60 (HSP60), DNA-dependent RNA polymerase subunit II (RPB2), and necrosis- and ethylene-inducing protein 1 and 2 (NEP1 and NEP2) genes that place them in a distinct group closely related to B. aclada, a globally distributed pathogen of onions. Genetic results were corroborated with morphological and pathogenicity trials that included two isolates of B. cinerea and two isolates of B. paeoniae from peony in Alaska and one isolate of B. aclada. The authors observed differences in colony and conidia morphology and ability to cause lesions on different host tissues that suggest that the grape and peony isolates represent a distinct species. Most notably, the grape and peony isolates did not colonize onion bulbs, whereas B. aclada readily produced lesions and prolific sporulation on onion tissue. The new species Botrytis euroamericana is described herein.
Keywords: Paeonia; Vitis; species recognition; taxonomy.