Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/8/2006
Publication Date: 6/15/2006
Citation: Sogonov, M., Castlebury, L.A., Mejia, L.C., Rossman, A.Y., White, J.F. 2006. GENERIC TRENDS IN THE GNOMONIACEAE, DIAPORTHALES. Meeting Abstract.
Technical Abstract: The Gnomoniaceae is a common but inconspicuous diaporthalean family of fungi associated with plants. Most occurring as symptomless endophytes of hardwood trees, some can be pathogenic. There are also some species associated with herbaceous plants and conifers. Usually they form ascomata on recently dead leaves or twigs. In earlier works based on morphological data, the family was defined as having single perithecia growing on non-woody plant tissues. The existence of the family as a separate entity in the order was confirmed by LSU rDNA sequence data by Castlebury et al. (2002). The main characters previously used for generic delimitation were presence/absence of stroma, position of the ostiole on the perithecia, ascospore shape and pattern of ascospore septation. The LSU dataset for the order Diaporthales has been significantly updated since 2002 and a dataset of over 200 ITS sequences representing ca. 100 gnomoniaceous species has been produced. Analysis of the sequence data has conflicted with the previous morphological studies. It has been revealed that some genera with perithecia formed in clusters on woody tissues definitely belonged in the Gnomoniaceae (Cryptodiaporthe, Cryptosporella). Some gnomoniaceous species have been found outside of the family-level clade. Classical generic concepts show limited correlation with the clades of the phylogenetic trees. Some clades show correlation with the plant host although species on several unrelated hosts also occur. For example, there are two well defined clades: one includes parasites of conifers so far known only as anamorphs (Sirococcus) while a second group on Fagales has clustered perithecia on woody substrata (Cryptosporella). ITS sequence data provide an initial overview of the generic trends. However resolution and support for clades that potentially represent genera are poor. Analysis of datasets of other genes (EF1, calmodulin, actin, RPB2) have clarified several genera within the family to date and the dataset is being expanded to representatives of the entire family based on the ITS and LSU results.8