The purpose of this research was to transform two economically important cultivars of strawberry with P5CS gene, which encodes Δ1-pyrroline-5-carboxylate synthetase (P5CS), the key enzyme in proline biosynthesis. Shoots were obtained on MS basal medium supplemented with 2% glucose and 4 mg/l TDZ for Camarosa and Kurdistan cultivars. For genetic transformation, a binary vector PBI121 containing P5CS gene under control of the 35SCaMV promoter was used. Transformed cells (explants) were regenerated on the selective regeneration medium containing 75 mg/l kanamycin and 500 mg/l cefotaxime after five days of pre-incubation and 72 h of co-cultivation with Agrobacter ium, while control explants failed to grow in the same medium. The presence of the transgene in the plant genome was confirmed by PCR. The morphology of the transgenic plants was normal as controls. Drought stress was applied using polyethylene glycol (PEG) 6000 at concentrations equal to 0, -5 and -7 Bar, respectively. Proline content was four times higher in the transformed leaves compared to that of the untransformed plants while the proline content in the roots was similar in both transgenic and wild-type plants. Overproduction of P5CS also increased chlorophyll content, shoot length, shoot fresh and dry weight in the transgenic plants under drought-stress conditions
