Precise genetic engineering with piggyBac transposon in plants.

Transposons are mobile genetic elements that can move to a different position within a genome or between genomes. They have long been used as a tool for genetic engineering, including transgenesis, insertional mutagenesis, and marker excision, in a variety of organisms. The piggyBac transposon derived from the cabbage looper moth is one of the most promising transposon tools ever identified because piggyBac has the advantage that it can transpose without leaving a footprint at the excised site. Applying the piggyBac transposon to precise genome editing in plants, we have demonstrated efficient and precise piggyBac transposon excision from a transgene locus integrated into the rice genome. Furthermore, introduction of only desired point mutations into the target gene can be achieved by a combination of precise gene modification via homologous recombination-mediated gene targeting with subsequent marker excision from target loci using piggyBac transposition in rice. In addition, we have designed a piggyBac -mediated transgenesis system for the temporary expression of sequence-specific nucleases to eliminate the transgene from the host genome without leaving unnecessary sequences after the successful induction of targeted mutagenesis via sequence-specific nucleases for use in vegetatively propagated plants. In this review, we summarize our previous works and the future prospects of genetic engineering with piggyBac transposon.