A quick method of Agrobacterium-mediated transformation protocol from immature embryos of tropical Indian maize genotypes

The principal obstacle in transferring desirable genes is the absence of an efficient regeneration and transformation protocol. In our study, we achieved successful plant regeneration and transformation by employing immature embryos derived from five tropical inbred lines of Zea mays, namely, V390, HK193-2, PV5, PV6 and HK1-163. Notably, the formation of embryogenic calli was observed within a brief 7-dayperiod and subsequent plant regeneration was accomplished within 30 days from the embryogenic callus on a culture medium containing MS supplemented with 1mg/L 6-Benzylaminopurine (BAP) and 0.1 mg/L Thidiazuron (TDZ). For the transformation experiments, we employed Agrobacterium tumefaciens EHA105 carrying the binary vector pCAMBIA 3301, which includes the bialophos/phosphinothricin resistance (bar) gene and the GUS reporter gene. After successful transformation, the regenerated plants underwent a hardening process and exhibited standard growth patterns. Among the five inbred lines, HKI 163 demonstrated the highest transformation efficiency (10.6%). The highlight of this protocol was the development of transgenic plants accomplished in a remarkably short period of approximately two months. This advancement sets the stage for future genome editing experiments within these inbred lines.