ABSTRACT
All organisms have to cope with DNA-damaging factors, with plants especially being exposed to many biological and environmental conditions causing DNA damage. Due to their sessile and phototrophic lifestyle, plants in particular have to face increased exposure to a wide variety of these factors such as UV radiation, site-specific biotic and abiotic environmental factors or reactive oxygen species. To further enhance genetic diversity, radiation such as X-rays or chemicals such as ethyl methanesulfonate (EMS) were used to increase the mutation rate. As a double-strand breaks (DSB) poses a major threat to genome integrity, plants have developed a complex repair network to cope with this kind of lesion. DSB repair can be classified into two different main repair pathways – non-homologous end joining (NHEJ) and homologous recombination (HR). All DSB repair pathways seem to compete with each other. NHEJ is the main repair pathway of DSBs in somatic plant cells and is responsible for random integration of DNA into plant genomes.
