Factors affecting delivery of <I>DREB۱A</I> gene in maize B۷۳ split-seeds via biolistic system

Immature embryos as a choice tissue for genetic transformation of maize have a few limitations, such as genotype dependence, time-consuming and requiring a well-equipped greenhouse for access, at any time. In the present study, the split-seed explants were used for genetic transformation of maize, B۷۳ line. The transformation of maize split-seed explants from the inbred line B۷۳, for resistance to abiotic stresses was carried out via particle bombardment using pCA-۳۵S-DREB construct, carrying Arabidopsis transcription factor DREB۱A under the control of the CaMV ۳۵S promoter and the selectable marker bar. For the optimization of gene-gun transformation parameters, we used two distances, ۶ and ۹ cm, one or double shooting and pre-treatment culturing of explants. The results showed that double shooting in ۹ cm under pre -treatment conditions can improve transient expression of GUS gene in split-seed explants. PCR analysis confirmed the presence of DREB۱A and bar genes in one out of ۱۱ transformants. The results showed that split-seeds of B۷۳ line can be used as a suitable explant for maize transformation.