Agrobacterium-mediated transformation system for the drought and excess light stress-tolerant wild watermelon (Citrullus lanatus)

• Published in: Plant Biotechnology 2005, Vol.22(1), pp.13-18
• Main Authors: Akashi, Kinya, Morikawa, Kaoru, Yokota, Akiho
• Format: Article
• Language: English
• Subjects: adventitious regeneration; Agrobacterium; Citrullus lanatus; Wild watermelon
• ISSN: 1342-4580; 1347-6114
• DOI: 10.5511/plantbiotechnology.22.13

Wild watermelon plants are drought and excess light stress-tolerant despite carrying out normal C3-type photosynthesis. In this study, a system was established for the genetic transformation of wild watermelons. Adventitious shoots were induced efficiently from cotyledon explants on medium containing 4 mg l−1 of benzyladenine. The explants were infected with Agrobacterium carrying a plasmid containing selectable marker genes, nptII (neomycin phosphotransferase), hpt (hygromycin phosphotransferase), and a reporter gene gusA (β-glucuronidase). A β-Glucuronidase (GUS) histochemical assay showed that kanamycin was more effective than hygromycin as the selective agent for transformation. The presence of T-DNA in the regenerated shoots was confirmed by amplification of the transgene using polymerase chain reaction. Southern blot analysis revealed stable integration of the transgene in the T1 progeny. The system presented here will provide an experimental basis for molecular studies of wild watermelon genes, and thus facilitate an understanding of their contribution to stress tolerance in this plant.