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United States Department of Agriculture

Agricultural Research Service

Research Project: SYSTEMATIC BIOLOGY OF INVASIVE AND EMERGING PLANT PATHOGENIC FUNGI
2007 Annual Report


1a.Objectives (from AD-416)
Characterize and analyze phylogenetic relationships for important disease-causing basidiomycetes with emphasis on smut and bunt fungi on cultivated grains and turf grasses, and rust fungi as pathogens of crops. Characterize and analyze phylogenetic relationships of ascomycetous pathogens based on morphological and molecular characteristics with emphasis on canker and related anthracnose fungi causing diseases of tree fruit crops and forest trees.


1b.Approach (from AD-416)
Smut and bunt fungi associated with turf grasses, cultivated grains, and weedy plants in the genera Tilletia, Ustilago, and Urocystis will be collected, cultured and characterized with morphological and molecular data. A wide range of rusts on weedy and crop plant hosts will be collected and characterized with DNA sequence data in order to determine both higher-level relationships and species relationships. Taxon-specific PCR primers will be developed for genes of interest when necessary. For both rusts and smuts PCR will be performed to amplify ribosomal and protein-coding genes, including ITS, LSU, SSU, EF1-alpha, and RNA polymerase gene regions. Species concepts will be defined based on multi-gene phylogenetic trees and morphological data when possible. Fungal pathogens of tropical hosts will be characterized with molecular data and ribosomal gene regions will be used to determine their relationships. Sequence data will be used to develop rapid methods for identification and correlated with morphological data when available. Diaporthalean taxa, including Diaporthe-Phomopsis and Valsa-Cytospora and taxa in the Nectria family of the Hypocreales will be collected and characterized morphologically. PCR will be performed to amplify ribosomal and protein-coding genes, including ITS, LSU, SSU, EF1-alpha, and RNA polymerase gene regions. Species concepts will be defined based on multi-gene phylogenetic trees in combination with morphological data. As new pathogens in these groups emerge, species previously unknown to science yet related to known pathogens in these groups will be described, illustrated and characterized. Taxonomic monographs will be published and made available as online resources.


4.Accomplishments
Devastating disease of sugarcane, Puccinia kuehnii, reported for the first time in the United States

Puccinia kuehnii is a rust fungus that causes a disease of sugarcane in Asia and Africa, but it was not known to occur in the continental United States. It is similar to Puccinia melanocephala that also causes a disease of sugarcane worldwide, including the United States. This research showed that P. kuehnii is now present in Florida and infecting cultivars of sugarcane that were resistant to P. melanocephala. DNA sequences and morphological features were used to identify P. kuehnii and distinguish it from P. melanocephala. This information will be useful to sugarcane breeders and producers in determining which cultivars should be planted and to pathologists in determining which rust fungus is causing disease on sugarcane.


5.Significant Activities that Support Special Target Populations
None


6.Technology Transfer

Number of non-peer reviewed presentations and proceedings3

Last Modified: 7/12/2014
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