Levels of phytoene and β-carotene in transgenic honeydew melon (Cucumis melo L. inodorus)

Using a previously reported optimized Agrobacterium tumefaciens-mediated transformation protocol, a watermelon phytoene synthase-C (PSY-C) gene was introduced into the elite honeydew breeding line '150'. Putative transformants were selected on kanamycin-containing medium (from 150 to 50 mg center dot l(-1)) and presence of the transgene was confirmed using polymerase chain reaction (PCR). Moreover, Southern blot analysis confirmed integration of the transgene and revealed presence of one to two copies of the PSY-C transgene in the different transgenic lines. In addition, reverse transcription (RT)-PCR analysis revealed transcript levels of the transgene in different tissues of these transgenic lines. Using flow cytometric analysis, it was found that all T-0 transgenic plants were tetraploid. Moreover, altered phenotypes (color change) were observed for rind tissues of transgenic lines. Based on high performance liquid chromatography (HPLC), beta-carotene content and phytoene accumulation in fruit of transgenic lines were 32-fold and 11 mu g center dot g(-1) FW higher than the levels found in the control plants.