title: Improvement of Agrobacterium-mediated transformation in Hi-II maize (Zea mays) using standard binary vectors.
abstract: High-frequency transformation of maize (Zea mays L.) using standard binary vectors is advantageous for functional genomics and other genetic engineering studies. Recent advances in Agrobacterium tumefaciens-mediated transformation of maize have made it possible for the public to transform maize using standard binary vectors without a need of the superbinary vector. While maize Hi-II has been a preferred maize genotype to use in various maize transformation efforts, there is still potential and need in further improving its transformation frequency. Here we report the enhanced Agrobacterium-mediated transformation of immature zygotic embryos of maize Hi-II using standard binary vectors. This improved transformation process employs low-salt media in combined use with antioxidant L-cysteine alone or L-cysteine and dithiothreitol (DTT) during the Agrobacterium infection stage. Three levels of N6 medium salts, 10, 50, and 100%, were tested. Both 10 and 50% salts were found to enhance the T-DNA transfer in Hi-II. Addition of DTT to the cocultivation medium also improves the T-DNA transformation. About 12% overall and the highest average of 18% transformation frequencies were achieved from a large number of experiments using immature embryos grown in various seasons. The enhanced transformation protocol established here will be advantageous for maize genetic engineering studies including transformation-based functional genomics.
authors.affiliation: Departamento de Genetica, Facultad de Biologia, Universidad Complutense, 28040 Madrid, Spain.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Vega
authors.forename: Weichang
authors.initials: W
authors.lastname: Yu
authors.forename: Angela R
authors.initials: AR
authors.lastname: Kennon
authors.forename: Xinlu
authors.initials: X
authors.lastname: Chen
authors.forename: Zhanyuan J
authors.initials: ZJ
authors.lastname: Zhang
mesh_terms: D015139:Blotting, Southern; D005822:Genetic Vectors / Q000235:genetics*; D030821:Plants, Genetically Modified; D012231:Rhizobium / Q000235:genetics*; D014170:Transformation, Genetic / Q000235:genetics*; D003313:Zea mays / Q000235:genetics* / Q000254:growth & development