Submitted to: Inoculum
Publication Type: Abstract Only
Publication Acceptance Date: 4/25/2005
Publication Date: 7/1/2005
Citation: Castlebury, L.A. 2005. The Diaporthe vaccinii complex of fruit pathogens. Inoculum. 56:12.
Technical Abstract: Diaporthe vaccinii (anamorph Phomopsis vaccinii) causes twig blight and upright dieback of Vaccinium corymbosum (blueberry) and V. macrocarpon (cranberry). However, other species of Diaporthe/Phomopsis have also been reported on Vaccinium spp. In addition, isolates from a variety of hosts are reported to be closely related to D. vaccinii. Relationships among this complex of fungi were characterized with the ITS regions of the nuclear rDNA and intron regions in the actin and translation elongation factor-1 alpha genes. Four species were resolved: D. vaccinii, P. fukushii, D. allegheniensis and an as-yet unidentified species with a broad host range. In this analysis, only D. vaccinii was host specific and limited to species of Vaccinium. Authentic isolates of P. fukushii, a pathogen of Pyrus, grouped with isolates from Vaccinium, Chamaecyparis and Ulmus. Diaporthe allegheniensis from Betula was most closely related to D. vaccinii. A large group of isolates from a variety of hosts including Vaccinium, Acer, Rubus, Malus, Corylus, Glycine, Viburnum and Vitis form a separate and well-supported species in this complex. Several isolates in this group are from specimens identified as D. eres, the type species of the genus, which has been reported to have a broad host range and variable morphology. Results of this study suggest that although certain pathogenic species in Diaporthe/Phomopsis may be host specific, many taxa in this genus will have a broad host range.