The Bxb1 recombination system demonstrates heritable transmission of site-specific excision in Arabidopsis

In this work, the Bxb1 recombinase gene was transformed and constitutively expressed in Arabidopsis thaliana plants harboring a chromosomally integrated attP and attB-flanked target sequence. The Bxb1 recombinase successfully excised the target sequence in a conservative manner and the resulting recombination event was heritably transmitted to subsequent generations in the absence of the recombinase transgene. In addition, we also show that Bxb1 recombinase expressing plants can be manually crossed with att-flanked target transgenic plants to generate excised progeny.The Bxb1 large serine recombinase performs site-specific recombination in Arabidopsis thaliana germinal tissue, producing stable lines free of unwanted DNA. The precise site-specific deletion produced by Bxb1 in planta demonstrates that this enzyme can be a useful tool for the genetic engineering of plants without selectable marker transgenes or other undesirable exogenous sequences.With the demonstration that foreign DNA can be stably introduced into plant cells in the 1980's, the generation of transgenic plants has become a commercial industry and its use in agriculture has continually grown with production surpassing 134 million Ha in 25 countries [1]. The most commonly enhanced traits being herbicide tolerance, pest resistance, or both traits stacked together [2]. The advancement of plant genetic engineering has led to more sophisticated techniques and strategies being utilized for value added crop production. For many years it has been known that the structure of a transgene locus can have a major influence on the level and stability of transgene expression. Therefore researchers have studied methods for precise DNA integration with particularly interest in how to stack transgenes 'cleanly' to prevent interaction with the plant's genome defense and silencing systems. The idea of 'clean' integration and or stacking benefits commercialization for it addresses concerns by the public and regulatory aut