Optimisation of <i>Agrobacterium</i> ‐mediated transformation in <i>Saintpaulia ionantha</i> H. Wendl using response surface methodology (RSM)

ABSTRACT Genetic transformation and regeneration procedures in Saintpaulia are dependent on different parameters, which limit the genetic manipulation efficiency. We focused on introducing an efficient model for gene transformation and regeneration after that, via RSM. Two commercial cultivars were transformed by the GUS reporter gene via Agrobacterium ‐mediated method. Results showed that variables infection time, BA and IAA concentrations, and cultivar type significantly ( p ≤ .05) affected gene transformation. According to the highest desirability (0.94) of the obtained model, the highest transformation rate was achieved (68.7%) by 15 s dip in bacterial suspension followed by regeneration steps in the medium supplemented with 100 µg/l BA + 1000 µg/l IAA. Subsequently, the given model validity was evaluated by a target gene ( etr1‐1 ). The highest rate of etr1‐1 transformation (76.25%) was achieved by 30 s infection time in the proposed medium containing 100 µg/l BA + 1000 µg/l IAA, according to the model. Genomic and reverse transcription PCRs confirmed that GUS, nptII and etr1‐1 genes were successfully integrated and expressed in both cultivars at each transformation. Our results indicate that optimising the time of infection and media using the RSM design could greatly improve the accuracy and feasibility of a model for achieving a high rate of genetic transformation.