Reporter gene-based recombination lines for studies of genome stability

Homologous recombination is a double-strand break repair mechanism operating in somatic cells and involved in meiotic crossovers in plants. It is responsible for the maintenance of genome stability and thus plays a crucial role in adaptation to stress. Recombination between homologous loci is believed to be regulated in part by epigenetic machinery such as methylation. Therefore, the recombination frequency at a specific locus can reflect the chromatin status.Several reporter gene-based recombination constructs have been developed to study HR frequencies in plants. Among them, the luciferase and beta-glucuronidase-based recombination reporter systems are the most widely used. Here, we explain how reporter gene recombination assays operate and in which applications they are used. We also present a conceptually new system for analysis of sequence-specific recombination frequency. These assays can be effectively used for analysis of locus-specific endogenous and stress-induced recombination frequencies.