2011 Field Crops Rust Symposium:
Phylogenetic Relationships Among Isolates of Uromyces Transversalis from Gladiolus × Hortulanus Based on its Sequence Data
Presenting Author: J. W. BUCK (1)
Coauthors: H. Avenot (1), A. Valencia-Botín (2), C. Palmer (3), S. N. Jeffers (4), K. Pedley (5)
Affiliations: (1) University of Georgia, Griffin, GA, USA; (2) Univ de Guadalajara, Guadalajara, Jalisco, Mexico; (3) IR-4, Princeton, NJ, USA; (4) Clemson University, Clemson, SC, USA; (5) USDA ARS FDWSRU, Ft. Detrick, MD, USA
Gladiolus rust caused by Uromyces transversalis is considered a pest of quarantine significance in the United States on cultivated gladiolus plants (Gladiolus ×hortulanus), which are grown primarily as a cut-flower crop but also in landscapes. Recent introductions of the pathogen into California and Florida have resulted in the implementation of quarantine and eradication measures at great cost to commercial growers. This pathogen is established in several gladiolus-exporting countries, including Mexico, which are potential avenues for the fungus to move into the United States. Twenty-seven isolates of U. transversalis were collected from commercial fields in Mexico in 2010–2011 for comparison to isolates from the United States (five), South Africa (one), New Zealand (one), and Australia (two). Phylogenetic relationships among these isolates were determined by amplifying and sequencing the internal transcribed spacer (ITS1, 5.8S gene, and ITS2) region of the rDNA-ITS. Preliminary phylogenetic (neighbor-joining and parsimony) analyses revealed that the isolates clustered into three groups, but clustering of the isolates based on geographic origin was not observed. The isolates from Mexico were distributed throughout the tree, suggesting some level of intraspecific variation.