Amount Awarded: $24,918
Domestication has had a tremendous effect on crop species-changing phenotypes, decreasing effective population sizes, and reducing genetic diversity. In addition to transforming the species under selection, it is increasingly appreciated that domestication also impacted crop pathogens. Ustilago maydis, the fungus that causes corn smut disease, has a paradoxical history as a scourge to farmers and a delicacy in Mexican cuisine. Surprisingly, genetic data suggest living U. maydis individuals-including those infecting the wild teosinte progenitor-descend from a common ancestor dating to the domestication of maize. To investigate whether recent maize breeding or propagation of the fungus for food may obscure the pathogen's evolutionary history, we will recover genomic sequences from historic corn smut. Samples of U. maydis will be collected at UC Berkeley's Jepson Herbarium and the US National Fungus Collections, processed at the historic DNA laboratory at the NTNU University Museum, and analyzed at UC Berkeley. In addition, modern U. maydis accessions will be used to generate a genomic reference panel to provide context for the historic specimens. We anticipate producing sufficient data for an exploratory article on historic U. maydis, while also launching a novel partnership to document co-evolutionary relationships between crops and pathogens.