Foote, Kedra D. , Meyer, Susan E. , Clement, Suzette , Stevens, Mikel R. .
Neutral genetic variation in Ustilago bullata populations from Bromus tectorum using amplified fragment length polymorphism markers.
Ustilago bullata is a smut pathogen that infects Bromus tectorum. The fungus is of special interest for its use as a biocontrol agent for cheatgrass. To understand the fungus, we are interested in how it varies genetically from location to location as well as within populations. In our study, we used amplified fragment length polymorphism (AFLP) markers to determine the diversity within and between eight populations of U. bullata from Utah, Nevada, Idaho, Oregon, and Washington. The Potosi Pass NV population had the highest gene diversity at 0.3528 with 88.89% polymorphic bands. The least diverse population was Buckskin Canyon NV, with a gene diversity value of 0.1977 and 55.56% polymorphic bands. Differences among populations accounted for 22.8% of the genetic variation, while the remainder (77.2%) was accounted for by within-population variation, indicating that most of the genetic variation in this sexually reproducing pathogen occurs within populations. A principal component analysis using genetic distances revealed that the three populations from northern Utah (ST, HC, and WR) are genetically similar, but that the other, widely separated populations could be more similar to each other than to more closely adjacent populations. This indicated a lack of support for an isolation-by-distance model of gene flow in this organism, which can disperse along with seeds of its host and thus benefit from targeted long-distance dispersal. Linkage disequilibrium analysis indicated that U. bullata is primarily inbreeding. Even though this pathogen must reproduce sexually in each generation, it is much more likely to mate with a close relative than with a distantly related strain.
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1 - Brigham Young University, Plant and Wildlife Sciences, 287 Widtsoe Building, Provo, Utah, 84602 , United States
2 - USDA Forest Service, Rocky Mountain Research Station, Shrub Sciences Laboratory, 735 N 500 E, Provo, Utah, 84606, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood D/Snowbird Center
Date: Tuesday, July 28th, 2009
Time: 10:15 AM