Use of TALEs and TALEN Technology for Genetic Improvement of Plants

Abstract

Genome editing with engineered nucleases has become a powerful tool of targeted genome modifications providing unprecedented control over animal and plant genetic material for precise, robust and highly specific genome engineering. Precise genome editing has been a long standing goal in the field of biology which has been achieved with the help of engineered nucleases like zinc finger nucleases, transcription activator-like effector nucleases (TALENs), and the Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated system. These engineered nucleases consist of a binding and a nuclease domain which are generally used in the form of a pair. The binding domain binds specifically to a DNA sequence whilst the nuclease domain creates double-strand breaks (DSBs) which are further used for non-homologous end joining or homologous recombination repair. Creation of DSBs is the principle of this technology which can be further used for gene addition, deletion and modification in the targeted DNA. Besides nuclease activity, TALE (transcription activator-like effector) proteins have also been used along with other effector domains for different purposes like gene activation, gene repression, epigenetic modifications, etc. The use of TALEs and TALENs for precise genome modifications of plants is now a common practice. So far, tens of crop plants have been modified using engineered nucleases like rice, wheat, tomato, potato, tobacco, maize, barley, cotton, etc. The TALE and TALEN technology is being used for development of biotic and abiotic stress-resistant plants as well as yield and quality improvement. In this article, we will briefly review and discuss TALEs and TALENs, their discovery, binding specificity, designing, functional domains, delivery and use for genome editing specifically in plants.