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United States Department of Agriculture

Agricultural Research Service

Systematic Monograph of the Gnomoniaceae - Overview
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The ascomycete order Diaporthales with the family Gnomoniaceae includes saprobic and plant pathogenic fungi of which the most notorious is the chestnut blight fungus that altered the landscape of eastern North America. Forest diseases caused by members of the Gnomoniaceae include oak dieback, cherry leaf scorch, sycamore canker, ash anthracnose, dogwood anthracnose, butternut canker, and many others. These microfungi include many serious emerging and invasive plant pathogens, thus knowledge of their taxonomic affinities is crucial for rapid detection, control of the diseases they cause, determining their origin, and preventing future introductions. Although of considerable economic importance, fungi in the Diaporthales have not received modern monographic treatment nor have their related asexual fungi been included in their limited literature. A monographic account of this understudied group is needed to provide the taxonomic framework for understanding the evolution of invasive asexual fungi such as the causes of dogwood anthracnose and butternut canker.

Objectives: The objective of this project is to monograph the ten major genera and related fungi of the ascomycete family Gnomoniaceae, Diaporthales, including their derived asexual species using a combination of morphological and molecular approaches. The three groups of genera of the Gnomoniaceae will be studied as separate but interrelated projects. Several hundred living cultures and reference specimens are available for each group with additional material to be acquired through collecting and collaborating with scientists throughout the world. The research approach involves examination of macroscopic and microscopic characters using high quality light and scanning electron microscopes. A digital image analysis system will be used for measuring, recording, and analyzing microscopic characters as well as for capturing images. Morphological data and molecular sequence data (LSU nrDNA) will be used to develop hypotheses about lineages within the Gnomoniaceae. These hypotheses will be tested using DNA sequence analyses of additional genes, specifically RNA polymerase B subunits 1 and 2, translation elongation factor 1 alpha, mit-ATP6 and mit-SSU rDNA genes individually and in combination. Monographic accounts of these fungi will be published in mycological journals and placed on the Internet as interactive keys supported by descriptions and illustrations.

Last Modified: 10/24/2005
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