Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/28/2001
Publication Date: N/A
Technical Abstract: Over 800 species of Phomopsis have been described primarily on the basis of host. The value of morphological characters in distinguishing species is limited due to the reduced features of the conidiomata. A further complication is that strains, even newly isolated ones, may not form pycnidia or perithecia in culture. Biologically, strains of Phomopsis are known to function as plant pathogens, endophytes or saprotrophs. Current molecular approaches to defining taxa in Phomopsis focus on analysis of the ITS rDNA, although it has not been particularly informative. Using an approximately 350 base pair region of the translation elongation factor-1 alpha gene, we found six closely related, well-supported groups among Phomopsis isolates from cucurbits. Three groups correspond to named taxa, P. longicolla, Diaporthe melonis, and the D. phaseolorum complex. Other isolates grouped with strains from diverse hosts and may represent endophytic species. The application of appropriate names to the unidentified genetically distinct taxa is problematic due to the absence of distinct morphological and/or cultural characters and biological information.