Plant genome editing by novel tools: TALEN and other sequence specific nucleases.

Genome editing technologies using sequence specific nucleases (SSNs) became a tremendously powerful and precise tool for reverse genetic approaches and applied biology. Transcription activator-like effector nucleases (TALENs) in particular, consisting of a free designable DNA binding domain and a nuclease, have been exploited today by a huge number of approaches in many different organisms. The convenience of designing the DNA binding domain and straightforward protocols for their assembly, as well as the broad number of applications in different scientific fields made it Natures method of the year 2011. TALENs act as molecular scissors by introducing double strand breaks (DSBs) to the DNA at a given location. The DSBs are subsequently repaired by the cell itself using different repair pathways such as non-homologous end joining (NHEJ) or homologous recombination (HR). These mechanisms can lead to deletions, insertions, replacements or larger chromosomal rearrangements. By offering a template DNA it is possible to channel the repair in direction of HR. In this article we review the recent findings in the field of SSN approaches with emphasis on plants.