Maize Genetic Transformation Mediated by Agrobacterium tumefaciens and Optimization of the Differentiation and Rhizogenesis Conditions

The maize immature embryos of five inbred lines,including ‘18-599(H)’,‘Qi 319’,‘Zong 31’,‘Z674’ and ‘Zheng 58’,were used to initiate embryogenic calli.Then,these calli were used for the maize transformation mediated by Agrobacterium tumefaciens.The stable expression of GUS gene in transgenic plants was confirmed by histochemical assay and the Hpt gene was identified by PCR.The results indicated that the five maize inbred lines were different in the embryogenic calli initiation,the rate of resistant calli and the transformation frequency.Our results suggest that transformation efficiencies of ‘18-599(H)’ and ‘Qi 319’ were significantly improved up to 6.1% and 3.5% with the optimizing differentiation and rhizogenesis conditions,respectively.