Identification of an effective vector constructed for maize transformation and study of PEG-mediated transformation method
A new vector, pB1S5, specifically used for maize transformation, has been constructed by using a plasmidlike S1 DNA fragment of maize. The transformation frequency of BMS protoplasts mediated by PEG with the new vector is twice as much as compared with the control. This result indicates that the new vector has striking enhancement effect on the transformation frequency of maize. Meanwhile, the study of the PEG-mediated transformation method has also been carried out. The results show that the appropriate PEG concentration is in the range of 6-10%, the optimum PEG treatment time and suitable foreign DNA concentration are 30 min and 40 mu-g/ml, respectively. These parameters coordinated with the specific experimental system will yield satisfactory results for maize protoplast transformation.