Applications of Genome Engineering/Editing Tools in Plants

The advent of engineered nucleases such as zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas9) has revolutionized targeted genome editing. CRISPR/Cas9-based editing system has surpassed its predecessors owing to its simplicity, versatility and efficiency. Therefore, it has become the most promising genome-editing tool in recent years which is evident through the increasing number of publications and in several organisms. This technology has profound applications in areas of functional genomics and crop improvement. Recent studies have proved that multiplex genome editing is possible not only in model crops but in major crops too. Unlike transgenic crops which yield random insertions of target genes, genome-editing tools enable targeted gene insertion at a specified locus (knock-in), deletion of desired genes from the genome (knockout) and also genome modification (replacement). In this context, this chapter describes in detail the various applications of genome-editing technologies in crop improvement and highlights how this tool has outwitted transgenic technology in recent times.