An Efficient Gene Excision System in Maize.

Use of the morphogenic genes () and (), along with new ternary constructs, has increased the genotype range and the type of explants that can be used for maize transformation. Further optimizing the expression pattern for / has resulted in rapid maize transformation methods that are faster and applicable to a broader range of inbreds. However, expression of / can compromise the quality of regenerated plants, leading to sterility.

Using Morphogenic Genes to Improve Recovery and Regeneration of Transgenic Plants.

Efficient transformation of numerous important crops remains a challenge, due predominantly to our inability to stimulate growth of transgenic cells capable of producing plants. For years, this difficulty has been partially addressed by tissue culture strategies that improve regeneration either through somatic embryogenesis or meristem formation. Identification of genes involved in these developmental processes, designated here as morphogenic genes, provides useful tools in transformation research.

High efficiency Agrobacterium-mediated site-specific gene integration in maize utilizing the FLP-FRT recombination system.

An efficient Agrobacterium-mediated site-specific integration (SSI) technology using the flipase/flipase recognition target (FLP/FRT) system in elite maize inbred lines is described. The system allows precise integration of a single copy of a donor DNA flanked by heterologous FRT sites into a predefined recombinant target line (RTL) containing the corresponding heterologous FRT sites. A promoter-trap system consisting of a pre-integrated promoter followed by an FRT site enables efficient selection of events.

Maize Transformation Using the Morphogenic Genes Baby Boom and Wuschel2.

Despite the fact that maize transformation has been available for over 25 years, the technology has remained too specialized, labor-intensive, and inefficient to be useful for the majority of academic labs. Compounding this problem, future demands in maize genome engineering will likely require a step change beyond what researchers view as "traditional" maize transformation methods. Recently, we published on our use of constitutively expressed morphogenic transcription factors Baby Boom (Bbm) and Wuschel2 (Wus2) to improve maize transformation, which requires CRE-mediated excision before regeneration of healthy, fertile T0 plants.

Effect of Agrobacterium strain and plasmid copy number on transformation frequency, event quality and usable event quality in an elite maize cultivar.

Improving Agrobacterium -mediated transformation frequency and event quality by increasing binary plasmid copy number and appropriate strain selection is reported in an elite maize cultivar. Agrobacterium-mediated maize transformation is a well-established method for gene testing and for introducing useful traits in a commercial biotech product pipeline. To develop a highly efficient maize transformation system, we investigated the effect of two Agrobacterium tumefaciens strains and three different binary plasmid origins of replication (ORI) on transformation frequency, vector backbone insertion, single copy event frequency (percentage of events which are single copy for all transgenes), quality event frequency (percentage of single copy events with no vector backbone insertions among all events generated; QE) and usable event quality frequency (transformation frequency times QE frequency; UE) in an elite maize cultivar PHR03.