Genotype-independent transformation technique development and application in maize

The genetic transformation of maize inbred lines via Agrobacterium tumefaciens is highly genotype-dependent. The morphogenetic genes Baby boom (Bbm) and Wuschel2 (Wus2) significantly enhance transformation efficiency and expand the range of amenable inbred lines. However, achieving transgenic seedlings remain challenging for many maize inbred lines, and the underlying mechanism remains unclear. In this study, we found that mixing the target vector with Bbm and Wus2 in a 10:1 ratio facilitates the generation of somatic embryos in most inbred lines. Transient transfection efficiency and the timing of selection are critical factors influencing the formation of somatic embryos and subsequent seedling development. By optimizing infection conditions and delaying selection, we established an efficient and rapid genetic transformation system that is not restricted by genotype. Using this system, we conducted genetic transformation on 131 inbred lines, resulting in successful transgenic plants in 104 of these lines.