AUTHOR=Yin Qian , Li Ruyu , Ow David W. 

TITLE=Site-Specific Sequence Exchange Between Homologous and Non-homologous Chromosomes

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.828960

DOI=10.3389/fpls.2022.828960

ISSN=1664-462X

ABSTRACT=Transgene integration typically takes place in an easy-to-transform laboratory variety before the transformation event is introgressed through backcrosses to elite cultivars.  As new traits are added to existing transgenic lines, site-specific integration can stack new transgenes into a previously-created transgenic locus.  In planta site-specific integration minimizes the number of segregating loci to assemble into a breeding line, but cannot break genetic linkage between the transgenic locus and nearby undesirable traits.  Here, we describe an additional feature of an in planta gene stacking scheme, in which the Cre recombinase not only deletes transgenic DNA no longer needed after transformation, but also mediates recombination between homologous or non-homologous chromosomes.  Although the target site must first be introgressed through conventional breeding, subsequent transgenes inserted into the same locus would be able to use Cre-mediated translocation to expedite a linkage drag-free introgression to field cultivars.