|Roelfs, Alan - RETIRED ARS EMPLOYEE|
Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 2002
Publication Date: June 1, 2002
Citation: SZABO, L.J., ROELFS, A. PHYLOGENETIC ANALYSIS OF THE PUCCINIA ANDROPOGONIS COMPLEX. AMERICAN PHYTOPATHOLOGICAL SOCIETY ABSTRACTS. 2002. v. 92. p. S79. Technical Abstract: The rust Puccinia andropogonis is a pathogen of North American grasses including Andropogon gerardii (big bluestem) and Schizachyrium scoparis (little bluestem). P. andropogonis is a macrocyclic heteroecious rust with uredinia and telia on grasses, and pycnia and aecia on a wide range of dicots in six families. Given the diversity of the aecial hosts, P. andropogonis is likely a species complex. DNA sequence analysis of the nuclear ITS rDNA from aecial and telial collections separated P. andropogonis into four groups that corresponded to aecial hosts: 1) Penstemon gracilis, P. grandiflorus (Scrophulariaceae); 2) Comandra umbellate (Santalaceae); 3) Ampicarpaea comosa, Lupinus perennis (Fabaceae); and 4) Xanthoxylum americanum (Rutaceae). Samples from the grass host A. gerardii fell into groups 2 and 4, while samples from S. scoparis fell into group 1. These data support the division of P. andropogonis into groups based on aecial hosts as described by Arthur (1962). However, the genetic distances between the groups (39-83 bp changes) suggest that these represent separate species.