Submitted to: Sydowia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/4/2005
Publication Date: 6/30/2005
Citation: Sogonov, M.V., Castlebury, L.A., Farr, D.F. Rossman, A.Y., White, J.F. 2005. The type species of the genus Gnomonia, G. gnomon, and the closely related G. setacea. Sydowia 57(1):102-120.
Interpretive Summary: Very small fungi in the group that causes chestnut blight also cause diseases on other economically important crops and trees. These fungi can easily be found on overwintered leaves, but are inconspicuous and poorly known. In order to define and characterize these small fungi, many specimens were collected in the forest. Back in the laboratory, the fungi were examined microscopically and grown as genetic resources. They were compared with the one-hundred year old reference specimens upon which these species were originally described and named. After examining both the old and new specimens, two fungal species that occur on hazelnut and other trees were described and illustrated using modern characteristics. Analyses of portions of the genomes of these fungi were used to determine that they are closely related to each other in a family that includes numerous disease-causing fungi. Using this information, plant pathologists will be able to identify these fungi when they are encountered as plant pathogens.
Technical Abstract: Species of the diaporthalean genus Gnomonia are common yet inconspicuous and poorly known microfungi occurring mostly on overwintered leaves of trees and shrubs in the temperate zone of the northern hemisphere. Confusion exists concerning the type species of Gnomonia because a type was not designated by the authors of the genus. Three specific names have been mentioned in the literature as the type species: G. gnomon, G. vulgaris and G. setacea. Gnomonia gnomon was designated as the lectotype species; however, some authors have considered all three taxa to be synonymous with G. setacea having priority. Gnomonia vulgaris is a nomenclatural synonym of G. gnomon. Observations of type specimens and fresh material of G. gnomon and G. setacea reveal that these two species are distinct and can be distinguished by position of the perithecium in the leaf tissue and ascospore morphology. Descriptions and illustrations of G. gnomon and G. setacea are provided and an epitype specimen with derived living culture for G. gnomon is designated. These observations are also supported by ribosomal DNA sequence analysis.