Experimental evolution of the co-adaptation of mais and its pathogen Exserohilum turcicum

SCHM 1354/1

Modern agroecosystems are characterised by a low ecological diversity. This leads to a strong evolutionary selection pressure between interacting species like crop plants and their pests. Maize is one of the most widely cultivated crop species worldwide and a highly suitable model for the study of evolutionary processes in agroecosystems because of it high diversity of varieties and genomic variability. In a multi-year experiment, the co-evolution of maize and one of its most important pathogen, the fungus Exserohilum turcicum, will be investigated. This fungus causes Northern Leaf Blight and spreads throughout Central Europe. Two different maize varieties that differ in their resistance against the fungus will be inoculated and the most resistant plants will be selected. The fungi will be separated by the population and transferred into the next generation. This generates a strong selection pressure for co-adaptation between maize and pathogen population. In each of the three planned selection cycles, the maize and pathogen population will be genotyped and investigated with the methods of population genetics. The analysis is aimed at testing whether pathogen evolution differs in response to different host populations and which evolutionary model best describes the change of host and pathogen populations. By such a comparison, statements on the importance of genetic diversity in the crop and its pest for the coevolution can be made the central factors for a rapid co-adaptation can be identified.