Media type: E-Article Title: Morphogenic Regulator‐Mediated Transformation of Maize Inbred B73 Contributor: Mookkan, Muruganantham; Nelson‐Vasilchik, Kimberly; Hague, Joel; Kausch, Albert; Zhang, Zhanyuan J. Published: Wiley, 2018 Published in: Current Protocols in Plant Biology, 3 (2018) 4 Language: English DOI: 10.1002/cppb.20075 ISSN: 2379-8068 Origination: Footnote: Description: <jats:title>Abstract</jats:title><jats:p>Maize B73 is a reference genome and has long been a major resource for genetics and molecular biology research. We have developed an efficient B73 transformation protocol by enabling somatic embryogenesis through differential co‐expression of maize morphogenic regulators <jats:italic>BBM</jats:italic> and <jats:italic>WUS2</jats:italic>. We describe a successful protocol that utilizes <jats:italic>Agrobacterium tumefaciens</jats:italic> strain AGL1 harboring binary vector PHP78891 that comprises a <jats:italic>BBM</jats:italic> and <jats:italic>WUS2</jats:italic> expression cassette as well as a green fluorescent protein (<jats:italic>GFP</jats:italic>) reporter cassette. The PHP78891 vector also contains, within the T‐DNA region, a <jats:italic>CRE/lox</jats:italic> recombination system flanking the CRE/<jats:italic>BBM/WUS2</jats:italic> co‐expression cassette driven by the desiccation inducible <jats:italic>RAB</jats:italic>17 promoter that allows removal of the <jats:italic>BBM/WUS2</jats:italic> cassette. Introduction and co‐expression of <jats:italic>BBM</jats:italic> and <jats:italic>WUS2</jats:italic> induced direct somatic embryogenesis (SE) in non‐regenerable maize B73 from immature embryo explants. Removal of the <jats:italic>CRE/BBM/WUS2</jats:italic> cassette is essential to allow regeneration to fertile plants. The <jats:italic>GFP</jats:italic> expression cassette outside the <jats:italic>lox</jats:italic> excision sites is retained in the transgenic plant genome, allowing subsequent phenotypic analysis of calli and regenerated transgenic events. This transformation system enables a selectable marker‐free transformation process by taking advantage of <jats:italic>BBM/WUS2</jats:italic>‐induced SE as a developmental selection system. © 2018 by John Wiley & Sons, Inc.</jats:p>