Diversity of a disease resistance gene homolog in Andropogon gerardii (poaceae) is correlated with precipitation

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dc.contributor.author Rouse, Matthew
dc.date.accessioned 2007-12-17T19:38:41Z
dc.date.available 2007-12-17T19:38:41Z
dc.date.issued 2007-12-17T19:38:41Z
dc.identifier.uri http://hdl.handle.net/2097/517
dc.description.abstract Ecological clines often result in gradients of disease pressure in natural plant communities, imposing a gradient of selection on disease resistance genes. We describe the diversity of a resistance gene homolog in natural populations of the dominant tallgrass prairie grass, Andropogon gerardii, across a precipitation gradient ranging from 47.63 cm/year in western Kansas to 104.7 cm/year in central Missouri. Since moisture facilitates infection by foliar bacterial pathogens, plants along this precipitation gradient will tend to experience heavier bacterial disease pressure to the east. In maize, the gene Rxo1 confers resistance to the pathogenic bacterium Burkholderia andropogonis. Rxo1 homologs have been identified in A. gerardii and B. andropogonis is known to infect natural populations of A. gerardii. The spatial genetic structure of A. gerardii was assessed from central Missouri to western Kansas by genotyping with AFLP markers. Samples were also genotyped for Rxo1 homologs by amplifying an 810 base pair region of the leucine-rich repeat and digesting with restriction enzymes. We compared Rxo1 homolog diversity to AFLP diversity across different spatial scales. Genetic dissimilarity based on AFLP markers was lower than would have occurred by chance at distances up to 30 m, and different prairies were more dissimilar than would have occurred by chance, but there was not a longitudinal trend in within-prairie dissimilarity as measured by AFLP markers. Dissimilarity of the Rxo1 homologs was higher in the east suggesting the presence of diversifying selection in the more disease-conducive eastern environments. en
dc.description.sponsorship The Land Institute; Ecological Genomics Institute en
dc.language.iso en_US en
dc.publisher Kansas State University en
dc.subject Genetic diversity en
dc.subject Amplified fragment length polymorphism en
dc.subject Spatial genetic structure en
dc.subject Polyploidy en
dc.subject Leucine-rich repeat en
dc.subject Andropogon gerardii en
dc.title Diversity of a disease resistance gene homolog in Andropogon gerardii (poaceae) is correlated with precipitation en
dc.type Thesis en
dc.description.degree Master of Science en
dc.description.level Masters en
dc.description.department Department of Plant Pathology en
dc.description.advisor Karen A. Garrett en
dc.subject.umi Agriculture, Plant Pathology (0480) en
dc.subject.umi Biology, Ecology (0329) en
dc.subject.umi Biology, Genetics (0369) en
dc.date.published 2007 en
dc.date.graduationmonth December en

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