@article {KNZ001395, title = {Genomic and resistance gene homolog diversity of the dominant tallgrass prairie species across the U.S. Great Plains precipitation gradient}, journal = {PLoS ONE}, volume = {6:e17641}, year = {2011}, abstract = {

Background Environmental variables such as moisture availability are often important in determining species prevalence and intraspecific diversity. The population genetic structure of dominant plant species in response to a cline of these variables has rarely been addressed. We evaluated the spatial genetic structure and diversity of Andropogon gerardii populations across the U.S. Great Plains precipitation gradient, ranging from approximately 48 cm/year to 105 cm/year. Methodology/Principal Findings Genomic diversity was evaluated with AFLP markers and diversity of a disease resistance gene homolog was evaluated by PCR-amplification and digestion with restriction enzymes. We determined the degree of spatial genetic structure using Mantel tests. Genomic and resistance gene homolog diversity were evaluated across prairies using Shannon\&$\#$39;s index and by averaging haplotype dissimilarity. Trends in diversity across prairies were determined using linear regression of diversity on average precipitation for each prairie. We identified significant spatial genetic structure, with genomic similarity decreasing as a function of distance between samples. However, our data indicated that genome-wide diversity did not vary consistently across the precipitation gradient. In contrast, we found that disease resistance gene homolog diversity was positively correlated with precipitation. Significance Prairie remnants differ in the genetic resources they maintain. Selection and evolution in this disease resistance homolog is environmentally dependent. Overall, we found that, though this environmental gradient may not predict genomic diversity, individual traits such as disease resistance genes may vary significantly.

}, keywords = {LTER-KNZ, Amplified fragment length polymorphism, Cloning, Hexaploidy, Maize, Plant genomics, Plant pathology, Ploidy, Population genetics}, doi = {10.1371/journal.pone.0017641}, url = {https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0017641}, author = {Rouse, M.N. and Saleh, A.A. and Seck, A. and Keeler, K.H. and Travers, S.E. and Hulbert, S.H. and Garrett, K.A.} } @article {KNZ001254, title = {Beyond yield: plant disease in the context of ecosystem services}, journal = {Phytopathology}, volume = {99}, year = {2009}, pages = {1228 -1236}, abstract = {

The ecosystem services concept provides a means to define successful disease management more broadly, beyond short-term crop yield evaluations. Plant disease can affect ecosystem services directly, such as through removal of plants providing services, or indirectly through the effects of disease management activities, including pesticide applications, tillage, and other methods of plant removal. Increased plant biodiversity may reduce disease risk if susceptible host tissue becomes less common, or may increase risk if additional plant species are important in completing pathogen life cycles. Arthropod and microbial biodiversity may play similar roles. Distant ecosystems may provide a disservice as the setting for the evolution of pathogens that later invade a focal ecosystem, where plants have not evolved defenses. Conversely, distant ecosystems may provide a service as sources of genetic resources of great value to agriculture, including disease resistance genes. Good policies are needed to support conservation and optimal use of genetic resources, protect ecosystems from exotic pathogens, and limit the homogeneity of agricultural systems. Research is needed to provide policy makers, farmers, and consumers with the information required for evaluating trade-offs in the pursuit of the full range of ecosystem services desired from managed and native ecosystems.

}, keywords = {LTER-KNZ, biological control}, doi = {10.1094/PHYTO-99-11-1228}, url = {https://apsjournals.apsnet.org/doi/10.1094/PHYTO-99-11-1228}, author = {Cheatham, M.R. and Rouse, M.N. and Esker, P.D. and Ignacio, S. and Pradel, W. and Raymundo, R. and Sparks, A.H. and Forbes, G.A. and Gordon, T.R. and Garrett, K.A.} } @mastersthesis {KNZ001163, title = {Diversity of a disease resistance gene homolog in Andropogon gerardii (Poaceae) is correlated with precipitation}, volume = {MS Thesis}, year = {2007}, pages = {1 -53}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, 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.

}, keywords = {LTER-KNZ, Amplified fragment length polymorphism, Andropogon gerardii, genetic diversity, Leucine-rich repeat, Polyploidy, Spatial genetic structure}, url = {http://hdl.handle.net/2097/517}, author = {Rouse, M.N.} } @article {KNZ001063, title = {Climate change effects on plant disease: from genes to ecosystems}, journal = {Annual Review of Phytopathology}, volume = {44}, year = {2006}, pages = {489 -509}, abstract = {Research in the effects of climate change on plant disease continues to be limited, but some striking progress has been made. At the genomic level, advances in technologies for the high-throughput analysis of gene expression have made it possible to begin discriminating responses to different biotic and abiotic stressors and potential trade-offs in responses. At the scale of the individual plant, enough experiments have been performed to begin synthesizing the effects of climate variables on infection rates, though pathosystem-specific characteristics make synthesis challenging. Models of plant disease have now been developed to incorporate more sophisticated climate predictions. At the population level, the adaptive potential of plant and pathogen populations may prove to be one of the most important predictors of the magnitude of climate change effects. Ecosystem ecologists are now addressing the role of plant disease in ecosystem processes and the challenge of scaling up from individual infection probabilities to epidemics and broader impacts.}, keywords = {LTER-KNZ}, doi = {10.1146/annurev.phyto.44.070505.143420}, author = {Garrett, K.A. and Dendy, S.P. and Frank, E.E. and Rouse, M.N. and Travers, S.E.} }