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.

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.

Rapid genotype "independent" L. (maize) transformation via direct somatic embryogenesis.

Constitutive expression of the L. (maize) morphogenic transcription factors () and () in maize can not only greatly increase transformation efficiency but can also induce phenotypic abnormalities and sterility. In an effort to alleviate the pleiotropic effects of constitutive expression, a genome wide search was undertaken to find suitable maize promoters to drive tissue and timing-specific expression of the transformation enhancing genes and .

Morphogenic Regulators and Improve Monocot Transformation.

While transformation of the major monocot crops is currently possible, the process typically remains confined to one or two genotypes per species, often with poor agronomics, and efficiencies that place these methods beyond the reach of most academic laboratories. Here, we report a transformation approach involving overexpression of the maize () () and maize () genes, which produced high transformation frequencies in numerous previously nontransformable maize inbred lines. For example, the Pioneer inbred PHH5G is recalcitrant to biolistic and transformation.