OCHRE · Oat CHRomosome Evolution and drivers enabling widespread terminal intergenomic translocations in polyploid species

Comparative genetic analysis of grasses, one of the most widely distributed plant families and including the three most important human foods, has demonstrated that different groups differ in the evolutionary presence of intergenomic chromosome translocations in polyploid species, including the important crops. The overall goal of our research group is to define the nature and mechanism of terminal intergenomic translocations in oats (Avena) where these are frequent, allowing us to model their contribution to cereal genome evolution. We hypothesize that terminal translocations between oat genomes are related to transposable element activity, a decrease in DNA methylation, and histone modifications that are differential between the genomes. We propose a focused series of complementary molecular cytogenetic, bioinformatic, and epigenetic studies on oat and wheat genomes to characterize this physical genome rearrangement process. A comprehensive model illustrating the potential mechanisms involved in terminal intergenomic translocations will be elucidated by the simultaneous hybridization with the use of genome-specific probes and retrotransposon sequences, and immunostaining of histones and 5-methylcytosine in mitotic cells. The research will reveal why genomes of oats show frequent intergenomic translocations, playing a significant role in their evolution, in contrast to wheats where the translocations are rare. The fundamental research has implications for breeding oats to exploit biodiversity through introgression from wild species, and perhaps enabling additional introgressions in wheat breeding.