Site-Specific Gene Integration in Rice

Site-specific gene integration is a powerful technique for ensuring stable transgene expression. Transgenic plants produced by conventional transformation techniques often display highly variable transgene expression, which is mostly attributed to integration patterns consisting of multiple copies of transgene constructs. Therefore, it is desirable to generate single-copy integrations, preferably in a characterized genomic position. Precise integration of foreign genes into a selected genomic position can be obtained by employing site-specific recombination systems derived from bacteria or yeast. P1 bacteriophage Cre-lox system has been particularly successful in directing precise integration of foreign genes into “previously engineered” genomic sites. The resulting transgenic plants display stable expression through successive generations. Therefore, site-specific integration approach is useful for streamlining production of transgenic plants.