Application of Beta-Glucuronidase Transient Expression for Selection of Maize Genotypes Competent for Genetic Transformation

Genetic transformation of inbred maize lines and F1 hybrids registered in Ukraine has been carried out. The study employed a biolistic method for genetic transformation of immature maize embryos that formed callus tissue and the pAHC25 vector containing the genes of phosphinothricin-N-acetyltransferase (bar) and β-glucuronidase (uidA). As a result of the transformation of callus tissue of maize genotypes, lines resistant to phosphinothricin and regenerated plants were obtained. The activity of β-glucuronidase in herbicide-resistant calli was detected. The presence of the bar gene in callus DNA was demonstrated by the PCR method. The rate of stable transformation ranged from 2.2 to 30% depending on the genotype. The relationship between the results of transient expression of the β-glucuronidase gene and stable genetic transformation was observed. The proposed protocol for genetic transformation of maize using the study of transient expression of the β-glucuronidase gene makes it possible to significantly simplify the process of selecting genotypes competent for genetic transformation and create transgenic organisms with new traits.