Dissociation (Ds) constructs, mapped Ds launch pads and a transiently-expressed transposase system suitable for localized insertional mutagenesis in rice

We have developed a transiently-expressed transposase (TET)-mediated Dissociation (Ds) insertional mutagenesis system for generating stable insertion lines in rice which will allow localized mutagenesis of a chromosomal region. In this system, a Ds containing T-DNA construct was used to produce Ds launch pad lines. Callus tissues, from single-copy Ds/T-DNA lines, were then transiently infected with Agrobacterium harbouring an immobile Ac (iAc) construct, also containing a green fluorescent protein gene (sgfpS65T) as the visual marker. We have regenerated stable Ds insertion lines at a frequency of 9–13% using selection for Ds excision and GFP counter selection against iAc and nearly half of them were unique insertion lines. Double transformants (iAc/Ds) were also obtained and their progeny yielded ~10% stable insertion lines following excision and visual marker screening with 50% redundancy. In general, more than 50% of the Ds reinsertions were within 1 cM of the launch pad. We have produced a large number of single-copy Ds/T-DNA launch pads distributed over the rice chromosomes and have further refined the Ds/T-DNA construct to enrich for “clean” single-copy T-DNA insertions. The availability of single copy “clean” Ds/T-DNA launch pads will facilitate chromosomal region-directed insertion mutagenesis. This system provides an opportunity for distribution of gene tagging tasks among collaborating laboratories on the basis of chromosomal locations. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.